Rotary Caterham 7

It seemed simple enough and actually quite an interesting project:  fit some management to a Mazda 13B Rotary Wankle engine. To make it even more interesting the engine was in a Caterham 7.

The existing set-up was a single 48mm Dellorto carb with one choke feeding each rotor.  I never drive a car on the road prior to conversion but we did run it up on the rolling road for a full throttle power run. This established our base line power at 188 bhp @ 7000 rpm.

The conversion did not go well right from the off. There were all sorts of wiring problems under the dash which we found while trying to locate a feed for the ECU. We made up a fuel pump and swirl pot to mount at the back of the car using the original carb fuel pump to feed the swirl pot. At the back we actually found THREE fuel pumps. It would appear they failed in succession and rather than do the job properly someone had just put a new pump alongside the old, repeating the process when the second pump failed. We put a proper filter in the line to protect the injection pump.

The next job was to remove the front pulley and fit a trigger wheel. Easy enough:  or so I thought. Taking the pulley off was a piece of cake and I soon had the wheel mounted and a plan for the bracket to hold the pick-up sensor. It was then just a case of popping the pulley back on...oh, it won’t go back.

A call to a mate who rebuilds/tunes these engines soon had me looking for the worry beads. The crank has a pair of rotary roller thrust bearings and if you take the pulley off they fall down and you can’t align them without taking the engine to bits, or taking the engine out and standing it on end! Being under time pressure I was not keen to take the engine out and opted to drop the sump and take off the water pump, oil pump, alternator and front cover. Then I could get to the thrust washers and the balance shaft that is keyed to the crank (this had also fallen down).

After it was all back together I made up the pick-up sensor bracket and slotted the mounting holes so I could swing it in and out to adjust the gap. Normally I would find a rough TDC by putting something down the plug hole but this was never going to work with an engine minus the pistons and a conventional bore. I resorted to using what I was told were the TDC marks on the front pulley which turned out to be about right to set the trigger wheel reference gap position.

That just left the oil pump that feeds engine oil up into the inlet manifold. This was connected to the carb throttle arm but I could not replicate that because we had a throttle pot in that position, on the 48m throttle body. We used a 48mm body because the carb was 48mm and it would match the manifold. I ended up making a second throttle cable system driven at a link ratio that duplicated the original pump movement. Time consuming but it works quite well.

With everything wired and plumbed she fired up pretty much straight away. I mapped it and tried different timing on the leading and trailing spark plugs and we finished up with a whopping 209 bhp at 7250 rpm. So job done then; mission accomplished – no way. I drove the car on the road and it was dreadful. With conventional mapping the engine would flat spot after being on the overrun and gulp air if you rapidly opened the throttle from a cruise condition. Snap throttle opening was okay.

It would appear that the ugly curved inlet manifold centrifuges the fuel onto the outside wall and if it dries out you get a flat spot. The answer was to run it much richer and then suffer the fuel consumption consequences. I ended up with three maps, one conventional map and two progressively richer. The car is fast, no doubt and the quirky exhaust note attracts a lot of attention but I think it may need another set of injectors much closer to the inlet ports. At the moment that’s just speculation and I am awaiting a road test by the car’s owner to see how the conversion stacks up against the 48mm Dellorto carb.

Updates

From the last issue I have a couple of updates on two cars we featured. The Lambo with the BMW V12 finally got mapped up on 12 cylinders with a new set of HT leads. 336bhp but needing some serious attention to the throttle cable system. Sticking was the main problem with a pedal heavy enough to be mistaken for a brake pedal

The Maserati engined Standard Nine almost got mapped with a fuel pump that delivered more than the original 150 bhp injection pump. We saw well over 350 bhp on part throttle but then we had a bit of a drastic failure with a fuel line. The hose burst spraying fuel all over the interior of the car. That one has gone off for re-plumbing with decent quality hoses and will come back once it is sorted. There was also an issue with the engine breather system pressurising the dry sump tank.

FIRE!

After the close call with the Maserati engine we had more drama with a VR6 engine in the back of a fibre glass car. I won’t go into details but the exhaust caught fire. The CO extinguisher put it out but it re-ignited as soon as the extinguisher was empty. The Powder one got it but what a mess!

That convinced me to invest in a set of extinguishers, CO, foam and powder, plus read up on how to use which one for what type of fire. They are now positioned about the building. We have never really had a problem in nearly 20 years of running the rolling road but seeing the thing re-ignite put a scare into us. I could see the building going up as well as the car!

Too Much

You really can have too much of a good thing. We had an engine on the Superflow Dyno a while back which kept detonating. When we stripped it the compression ratio was 15.8 to 1! Last week we had another problem K which would not take any advance without detonating. Not simple Pinking but really banging off. A quick check with the compression gauge showed another mega compression ratio. Not on the stop of the gauge like the previous engine but real close. Come on guys, if you build an engine you are supposed to measure the compression ratio with a burette, not put the thing together and just expect it to be all right.

While I was waiting for the starter system for the Dyno (mentioned last issue) I managed to get our K Series VVC project engine up and running. Using the Frontline starter kit to spin it over she was soon fired up and I watched all the dials as the engine warmed up. I was so keen to get mapping that I did not notice that the VVC mechanism was not moving. I managed to get the engine mapped but with a disappointing 143 bhp at a little over 5500rpm. Not right at all.

A few checks on the software settings showed everything to be okay so it had to be a mechanical problem with the engine. This was a second-hand unit from a known car and it was working fine when we lifted it out (or so we assumed). Biting the bullet we removed the VVC control section and tried to move the cams. Nothing doing, we ended up removing the mechanism from the gearbox end of the engine as that seemed to be the problem bit. Amazingly we found a piece of the mechanism floating about and jamming the movement. It looks like someone changed the belt and made a mess of it; it can’t have worked for years.

The only way to get it all back together properly was to remove the cam carrier and assemble it all on the bench, thanks to some help from DVA Power. Finally we had a working VVC mechanism and the engine made 158bhp. That power was recorded by allowing the dyno to accelerate at 200rpm/sec which we reckon duplicated the rolling road accel rate (give or take).  Out of interest I ran the engine up to peak rpm and then applied load. I let it stabilise and then recorded 163.5 bhp at 7000rpm. Why the difference?

The difference is down to something called “slew rate”. I am indebted to my good mate Paul Cronin (sometime PPC contributor) for the info on slew rates and how the Industry tests their engines. If the engine is accelerating, some of the engine power goes into driving the flywheel, crankshaft, dyno shaft, etc. This reduces the power available at the load cell on the dyno. Once the engine stops accelerating the power goes up because the losses from accelerating the engine are no longer there. In the motor industry the norm is to hold the load until everything has stabilised and then record the power. A step test in fact with about 30 seconds between steps.

This makes the pub arguments about power outputs even more amusing because the way you measure the power alters the result. I think the ultimate question is, and always has been, “does it go okay?”

Exhaust tests

Last issue I had planned to bring you this test but starter and VVC problems delayed it. I had three exhaust systems for the K engine; the 4-2-1system to fit the K in the Midget, the 4-1 from GBS featured last issue and a full race work of art, long primary 4-2-1. When I say work of art I mean a fabulously constructed stainless TIG welded manifold with polished headers, all superbly blended at the welds.

The Frontline 4-2-1 was the manifold that produced 158 bhp at 7000rpm complete with the car’s silencer system. The engine was fully mapped on this manifold as this is the one that fits the car. Next I replaced the Frontline 4-2-1 with the GBS system destined for my Westfield, but retained the frontline silencer system to keep everything else the same. The power was up slightly at the top end with the 4-1 but back in the day the 4-2-1 was reckoned to give more mid-range torque; it didn’t. The 4-1 was just as good across the middle of the rev range and at peak there was only 2 bhp more across the last 1000rpm. Hardly worth worrying about.

Finally I installed the racer system, long primary 4-2-1 but I had to use an Elise race silencer as the Frontline kit is for a Midget (north south installation) and the manifold was for an Elise racer.  I was gobsmacked at the result. Okay, it was a standard engine and I would not have been surprised to see a small gain, or even a small loss, but it was night and day. The race system was hopeless on this standard engine! Torque was down right across the rev range and it never actually peaked. For a standard engine road car this manifold would be a disaster.

I don’t think this was actually down to the long primary 4-2-1 design; it was more the pipe size. The two road systems had pipe diameters of about 38mm (O/D) while the race system was 45mm. Years ago I remember Norton reducing the pipe diameter on their Super Sports model to gain power, must be something to do with gas speed in the pipe I figured at the time – and then fitted a bigger diameter pipe when I tuned my engine. Like most people I am endowed with more than my fair share of greed genes, bigger has to be better...

Rolling road

Back on the rolling road things were going better. We had the Chris Palmer XJS racer back in and this got back to his best ever previous power. We had a mystery misfire but Karl put the scope on the crank sensor and found a damaged tooth that showed up on the scope trace. He modified the ECU to overcome the problem and all was well.

Duratec

The Duratec engine on the rollers wasn’t doing so well after initial mapping so we had to have a look at the engine. The theory is that the car comes in; we strap it down and map the engine. It seldom, if ever, works out like that. I always start with a cylinder leakage test and if that shows up okay you at least know that the engine is sound. Next we double check for full throttle to make sure nothing has moved. Then I tend to lean towards cam timing. If it is an engine/cam combination that I know I can go straight to those settings, otherwise you are second-guessing in the hope that you can find the best timing before the valves hit the piston!

The Duratec does run close as standard but most engine builders cut the pockets for extra clearance when fitting cams or use pistons with bigger/deeper cut-outs. This one was quite a bit out and we made some nice gains from re-timing the cams.

TVR Power

We see quite a few TVRs here and I love the V8 sound (not had many six pots here). Just lately the most popular mod is to fit the Chevvy LS engine. This example had an LS3 and it made way over 400bhp on a stock engine. Compared to the engine size that might not be wonderful in terms of bhp/litre but it is still over 400 bhp with torque everywhere in the rev range. Unless you really do want to keep the car original it is the way to go. Rover engine owners have the option of a supercharger conversion (SC Power conversions seem to work well) while the AJP engine owners have the option of going from 4.2 to 4.5 litres. For my money though the LS conversion takes some beating.

Passing the MoT

Last issue I mentioned some testing I was doing about passing the MoT test. To pass a basic MoT test any modern engine will have to be fitted with a working catalytic converter. The mixture will be set to 14.7 to 1 AFR and either stay there for the duration of the test or "swing" across 14.7 to 1, under a closed loop setting. That's all you can do but it helps to have the throttle open a little on idle by setting the timing to zero degrees BTDC on idle. You can also employ a few tricks to help stabilise the rpm at the test point. For example: at 2500rpm (which is the fast idle test area) you can advance the timing at that point and retard it significantly either side of 2500rpm. The timing tends to "suck" the engine into staying at 2500rpm as the power drops away either side of that point. This is a very good reason for having map-switching, as the engine will not want to drive very nicely set up like that.

On the fuel map you will find the closed loop or adaptive map. You can set it to closed loop around the MoT points only for an MoT map. You can have every load site on a different strategy if you can think of a reason to!

Not all engines will pass an MoT test no matter what you do with them. The worst possible scenario is an engine fitted with full race cams, big throttle bodies where the butterfly is positioned for maximum power, and big injectors with a poor spray pattern.

Ideally the injectors should be selected to give maximum fuelling at about 80 to 90 per cent of the available time and have a good "fog" type spray pattern. The throttle butterfly wants to be as close to the inlet port as you can get it, to kill any pulse reversion on idle. If you have an engine with big cams and a plenum type intake you have no hope at all of passing the MoT or getting a smooth idle and light throttle drive. The injector position needs to be as close to the inlet valve, or valves, as you can get it with a good fog type nozzle. The nozzle spray pattern is more important than the siting of the injector if you want to keep the hydrocarbon emissions low.

I did some quick tests with the gas analyser using our mule 2.3 Duratec engine. I had two sets of injectors, one set with a fog type spray and another with a twin pencil spray. The injectors were tested in two positions; up in the head where Ford put them and out in the Jenvey throttle body. I did power runs with both injectors in both positions and the power was pretty much exactly the same regardless of injector type and position. You have to bear in mind that this is a standard engine, no porting or cams of any description.

When it came to the gas tests it was a very different story. The twin pencil spray injector was really poor on hydrocarbons when fitted to the Jenveys and not a lot better when put into the head. The fog type injectors were nothing less than brilliant in the head and not a lot worse when fitted into the throttle bodies. The HC readings went from the hundreds with the twin pencil injectors down to just 6ppm with the fog type injectors. All the modern injectors that we see have this multi-hole approach to break up the fuel. Everything these days is driven by emissions and economy but it is nice to know that this was not costing us any power on the test engine.

If all goes according to plan (does it ever?) next month I will be playing with a VVC K-series engine and trying out a few different exhaust designs.

BMW Mini

We did our first BMW Mini here at Emerald, basically a competition car fitted with throttle bodies. The reason we have not done these before is the fact that they run a drive-by-wire throttle and also there simply hasn’t been the demand. The throttle isn’t such a problem for our K6 because we now have the drivers in the ECU but I am not sure about the demand. We have a Mini specialist opposite us here in Norfolk and he reckons that the gearbox is a weak point so maybe that limits people’s enthusiasm for tuning?

Frozen 7

It is not uncommon for people to make a rolling road booking and not turn up. What is unusual is for a Caterham Seven owner to not only turn up but to drive here across country in a snow blizzard. What’s more the car was only running on a base map so it wasn’t the easiest of things to drive. We have done zillions of K engines here but this one was interesting in that the trumpets had been extended with home-made spacers. They did what they always do; make better low speed torque.

After mapping the car was driven back out into the snow and off to Northern Ireland.

F5000

Now this one really was a challenge as it also turned up in the middle of a snow storm albeit not being driven on the road! The car is a historic F5000 fitted with a V8, sporting mechanical injection. I only normally use the rolling road for mapping our ECUs but this one was just too interesting to turn down. The team had some shims and cams to alter the fuelling and basically all I had to do was drive the car and report on the fuelling.

Problem number one was getting the car to fit the rollers. The back end is so wide we had to take the end plates off the chassis section of the dyno to make clearance. Problem number two was getting me into the car. The regular driver uses a foam seat insert and there was no way to squeeze my aging and expanding body into the seat. I ended up sitting on the bare floor with some padding material.

Traction was problem number three because every time we tried to do a power run the power came in so suddenly that it broke free. Eventually I worked out that we could maintain traction if I set the rpm to steady state and applied the load gently down to full throttle. It was like a step test but done manually. Check out the picture of the intake trumpets, you may be able to see the fuel stand-off in the picture. There’s nothing you can do about this, it’s just a fact of life with carbs or mechanical injection. It tends to suggest that the trumpets are the wrong length, the wrong shape or a combination of both.

We did get the full-throttle fuelling somewhere near right but it is so frustrating when you know that with an ECU you could have it perfect and so much more driveable. But then it would not be historic so poor carburetion is all part of the game when you are re-living the past. Somebody pass the rose tinted spectacles!

Training

I started this month talking about MoT testing because I get so many calls on how to map engines I thought it might help if I put some of this stuff down in writing. Then I started to think that maybe some sort of training might be in order. I have had people here before but when you are mapping an engine it isn’t always possible to keep stopping and explaining why you are doing something or how you are going about it.

For that reason I am putting together some briefing notes to include in a classroom training day seminar on how to map engines. This isn’t just a software lesson, I wanted to pass on some of the practical experience I have gained in the last 20 years (I have now mapped over 3000 engines), in a more formal environment. No firm idea on cost but I am guessing something like £140 for the day, it depends on how much a buffet lunch is going to cost and the hire of the room. I wanted to keep it to no more than 12 people, assuming there might be 12 people out there that are interested in what I have to say on the subject. If I get enough interest then I will organise it. I already have nearly 6000 words of briefing notes to accompany the seminar and am sorting out example pictures and demo software. If any readers are up for it they can register their interest with Emerald on 01953 889110.

It's Dyno time

As I write this it is nearly Christmas and Santa has brought me a great present in the form of a Superflow 902 engine dynamometer. We have installed a test engine just to experiment a bit and get to know how it all works. The software is very different from the TAT kit we use on the rolling road and I have had to go back to school to pick it all up.

I have to confess it felt a bit strange sitting at the consul and feeling totally clueless, even a bit confused. I have been operating the rolling road for over 17 years now and I do it without thinking about anything other than what I am trying to achieve. With the Dyno I had to search around the screens to see what’s located where. I have to say that on the first power run I was more than a little nervous.

At first I was a bit disappointed because I was getting different results depending on how I tested the engine. But I had a word with Aaron Tucker at H.T. Racing - who has run a Superflow for a number of years and Aaron said that this was correct because you will get a different result on a step test compared to an acceleration run. The norm is to accelerate at 200 rpm/sec and log in set rpm steps, rather than try and log every point that the software is capable of logging. A run on the 2.3 Duratec mule engine took about 20 seconds which relates very closely to the rolling road power run. That has now become my standard with logging in 250 rpm steps.

I mapped the engine on steady-state running and it was just so easy. The drive-by-wire set up we have puts the load dead centre, then you release the throttle brake, dial in the rpm and the 902 does the rest. The stock engine makes 143 bhp at 5750 rpm and 154 ft lbs of torque at 4250 rpm. With Jenvey 45m bodies, my adjustable intakes and a Westfield 4-2-1 exhaust we recorded 170 bhp and over 180 ft lbs of torque.

Having started to get the hang of things I looked about for something to test. I have had a lot of enquires about inlet lengths since developing the ALI (Adjustable Length Inlet) but I did not want to go over old ground so I came up with another test. People keep asking me if a curved intake loses power and I have always said that I did not think it would lose much, if anything at all. So, there’s only one way to be sure.

I bought in four 90 degree silicon bends and cut up some of our intake trumpets. I tried to get the lengths the same for the straight intakes and the 90 degree ones but I may have been a few millimetres out. I took three “pulls” (see how quickly I am learning the Dyno tuning lingo) with the straight trumpets and then used the software to draw an average curve. Next I made up the curved intakes and the first run looked pretty much like the straight ones. The next two however seemed a little down. Not to worry, I can average out the results for consistency.

At that point young John came in and asked why I was running the engine with one bell-mouth missing! Being a cheapskate I just pushed the bell into the rubber hose and left off the clips. I was trying to save the cost of four cable ties...

We found the bell on the floor and four cable ties later I repeated the test and averaged out the results. At first sight the curved intakes looked to have lost power, but when you look at the scale the difference was tiny, just a couple of bhp at peak. Okay, it’s still a loss but it’s very small and interestingly right across the rev range. This is not an air flow issue; you can see how that looks on the Fiesta test elsewhere in these pages. I believe it is the curve taking the edge off the intake pulse and so marginally reducing the effect. If I had done these tests on a rolling road I would probably now be telling you that it makes no difference but the Superflow looks like it is going to be deadly in finding small differences. More dyno fun next issue!

Fiesta Fun

This is the engine that we did all the original testing on for the adjustable inlet system. The engine is now installed in a newer Fiesta and fitted with our Pipercross foam filters. Just to make sure everything was still sound we ran it up on the rolling road. The install wasn’t quite allowing full throttle but we still had 178 bhp. This is only a few bhp down on the original test. However, looking at the bonnet it was obvious that this would sit on top of the filter the way we had everything positioned. For that reason we shut the lid and did another power run.

You can see that up to 5,500 rpm there was nothing in it, but at peak torque the restricted filters started to hold the engine back. We lost 5 bhp at peak – just by closing the bonnet. This is not the first time I have seen this. We had a TVR some year’s back that dropped 20 bhp with the bonnet shut. It pays not to get too carried away when mapping and to do a final power run with the bonnet shut if it looks like getting in the way of the air flow.

K Series Capers

David Harvey’s 340R is a regular here at Emerald and David has tested more K Series engine configurations than you can shake a stick at. He currently runs a self-built 2.0 litre engine. This is a serious piece of kit and we recently did some testing on inlet lengths and shapes. Dave ended up with his chosen trumpet and air box configuration which gave him the torque in the right place (for a race car) and 248 bhp at peak power.

What’s really interesting is that if you take the air box off and record a power run the engine drops power everywhere and doesn’t want to run past 6,500rpm. Peak is normally up at 8,250 rpm. The air box is essential to make the engine work. We have done a lot of work on a Datsun 240Z that does the same airbox trick, but that one drops nearer 30bhp. This is yet another area for dyno investigation but that can wait until I have had a play with a few other things.

A broken ebay record

I hate to sound like a broken record but I am sick to death of seeing Chinese rubbish here in the workshop. I know it is cheap and Ebay make a fortune from selling it but if it doesn’t work then it isn’t cheap. Take this superbly anodised fuel pressure regulator, a direct replacement for the original. On the face of it, it works. But when you apply a vacuum, or pressurise the unit, the fuel pressure does not move. Any turbocharged car must have a rising rate regulator, this one does not even respond to vacuum, let alone boost. So how cheap is it when you have to buy another one and have had a wasted journey to the rolling road?

1.8 Turbo

I see an awful lot of VW 1.8T engines here and we regularly do this little mod to the throttle body. The stock ECU does the idle, (even though it is a cable throttle), through the drive-by-wire motor on the body. The way it works is that the throttle is almost closed and then the VW ECU adjusts the throttle to give the desired idle speed.

When you fit any aftermarket ECU you then find that the car idles at about 500 rpm. We drill out the body and use an Allen bolt as a throttle stop. I don’t bother with a lock nut; I just put a dab of Loctite on the thread and wait for it to go off. With engine heat this is only a matter of less than a minute. This allows you to set the throttle with very low ignition advance on idle. That way when the engine is cold the idle stabilisation system, using the ignition advance, has some air to work with and you have half a chance of the cold idle holding up.

Filters

We do a fair bit of testing on the rolling road; it isn’t all just mapping. One of the things we have looked at in the past is air filters. Just to give you an example we tried several different filters on a certain bog stock K Series engine and could not find one that gave more power than the original stock filter. The aftermarket filters can come into their own once you start modifying the engine though. But you have to think about how you install them.

We had a Zetec 1600cc engine on the rollers and when we fitted the filters over the intake trumpets the power held up no problem. Not quite job done though. When you shut the bonnet it looks like the air filters are somewhat restricted. Sure enough, a power run with the bonnet closed resulted in a loss of 5 bhp. If you look at the power curve you can see how the bonnet-down flow started to restrict air flow from 6000rpm onwards. Below that there was no real change.

While we are talking about filters, do bear in mind that the filtering agent in all these filters is the oil that you coat the filter’s surface in. The medium, be it cotton of foam is just there to hold the oil. No oil on the filter means it will not filter much beyond the odd passing brick!

Turbo Pipe

Young Jono here has sold his Fiesta and replaced it with an Audi A3 Turbo. Naturally, being young and having a pulse, he wants to play with the engine. The 1.8T engine is very tuneable but like all engines you do need money if you want the best from it. Our own Golf has a KO4 turbo and big bore exhaust and it makes over 280bhp – too much for the car (on the road) if we are honest.

A big part of getting power from a 1.8T is the exhaust system on these cars. The stock outlet pipe is pretty mean in terms of diameter so Jono has “invested” in a Piper Exhausts’ outlet pipe. You can see the difference in the pics. With no other mods this gave him a power gain over stock and we are regarding it here as an investment for when he does get the bigger turbo.

Lotus Elan

It was always a bit of a small car in its day but when you look at the original Elan now against a so-called “Super-Mini” it is tiny. This example was re-built by Spyder Cars and they fit the Ford Zetec engine in place of the original twin cam. A stock Zetec with throttle bodies makes anywhere from 160 to 170 bhp with perfect road manners. The original Twink made 105 to 115 bhp and has all the bad manners of a competition engine. This was the car of my dreams when I was a lad; it still looks perfectly proportioned to my aging eyes!

Superflow engine dyno

It has been a long haul but the Superflow 902 engine dyno here at Emerald is finally up and running! We have a 2.3 Duratec in place and are using it as a mule to gain experience with the kit. I have to say that I love it. You can sit in comfort and map away without ear defenders for a start. I keep looking at the water temperature (after all the years on the rolling road it is a habit I can’t seem to break) but the temperature hardly moves. That’s one advantage of a 1000 gallon radiator! We can see the water temp going into the engine at 70 degrees and coming back at about 75 degrees - when the engine is making something like 40 bhp.

It was the throttle control that took some time to sort out and held things up. The system comes with an hydraulic throttle on the console but initially we had problems with it not staying on the arm’s brake. You put on some load and the lever creeps back, reducing the throttle setting. I fixed that by routing the throttle cable from the lever to the bodies but then it did not respond to snap throttle closing. You could see from the software that snapping back the throttle did not result in the butterflies closing straight away. If something does go wrong I want to be able to shut off the power a.s.a.p. so I wasn’t happy with the hydraulic throttle.

A super long cable would not work so I looked into Drive-by-Wire. I found a motor from a BMW M3 that basically linked to the BMW throttle bodies via an arm. It was a simple matter to extend the arm and then have that work a very short throttle cable. The K6 ECU has the hardware to run drive-by-wire throttles but it isn’t released yet. We have a test ECU now on the dyno operated from a throttle pot that we mounted the Superflow hydraulic throttle arm. It works perfectly; you can’t move the arm faster than the throttle bodies respond no matter how fast you push or pull on the lever. It also stays exactly where you put it, making mapping a lot easier. At the moment the dyno is just for us to play with and we plan to use it to develop new features for the K6 ECU. Think of it as Dave’s early Christmas present to himself!

Getting out and about - again

I managed to escape the workshop again this month with a second visit to Clive Atthowe in Norwich. Clive was looking at a re-map for me on a Subaru WRX using his ECUTEK software. Previously we couldn’t complete the job because the pre-cat lambda had failed and the Subaru system relies heavily on the lambda sensor for its mapping.

With a new wide band sensor fitted, Clive and his buddy Dan set about taking a power run and logging the boost. Nothing wonderful by way of power was recorded - basically because the boost was too low. First step was to check the restrictor (what Clive called the “pill”) in the line to the boost valve. The smaller the hole, the higher the boost. It proved to be okay but then Clive realised that the plumbing on the valve was all wrong.

The car has been fitted with an aftermarket boost controller but this isn’t really the way to go. The stock ECU can alter the boost if the sensors report a problem, like pinking or detonation. Once you move control to an aftermarket system the ECU can no longer function properly. What we ended up with was a power level of 317 bhp but with the injectors running flat out. The car really needs larger injectors and probably a bigger fuel pump to keep up with fuel demand. It was interesting for me to see that Clive and Dan meet all the same problems that I see on a regular basis. I had always imagined that I am the only one who ever has problems on the rolling road!

Mystery misfire

The VW 1.8T engine is probably the most popular conversion for the Golf and I see no end of them here. This one was in for mapping and driving okay so in theory it was a straightforward calibration job. The owner had explained that he had previously had a misfire problem that was caused by the hydraulic tappets holding open on idle. New followers had cured the idle misfire albeit at some expense.

As it arrived the engine would not idle and I set about drilling the stock throttle body to add a simple throttle stop. We do this all the time so there was no mystery involved. We soon had a stable tick over but it wasn’t very smooth. These engines run like sewing machines normally so I went down the fuel rail pulling off one injector plug at a time and checking the idle speed. Sure enough, number four wasn’t doing anything on idle. However, when you picked the revs up it fired up okay. Was this the hydraulic tappet problem come back to haunt us?

No, it wasn’t. A simple check showed that the injector was getting the pulse from the ECU on idle but the injector was not reacting. You can confirm this by listening to the injector with a stethoscope (or a screwdriver pressed to your ear). When the revs picked up the longer injector pulse brought the injector to life.

I still mapped the car okay but the idle would need sorting out once the injector had been changed. What was interesting was that this engine was fitted with an LPG conversion. The LPG ECU simply follows the original ECU signal so in theory there’s no mapping needed on gas. This works really well with the Emerald ECU because you can switch to a second map when the gas is activated. Then you can map the gas as if it was just another petrol map. The lambda reading of the mixture stays the same so you don’t even have to think about it, you just map as per normal. The fact that the AFR reading says 14.7 to 1 (when in reality it isn’t) doesn’t change the fact that this is still the correct mixture for LPG even though it isn’t actually 14.7.

This is the system that our Will needs to adopt for his LPG conversion on this V8 Merc instead of playing about with outdated kit bought cheap on Ebay. With the cost of petrol only going one way I am seriously looking at an LPG conversion on my own Mazda 4x4. With our ECU I can map the LPG to get the mixture exactly right, run a little more advance on light throttle, and get the best MPG figure I can for the gas. LPG is cheap but it still isn’t free so I can’t see any excuse for wasting it.

Supercharged MX5

These are great little cars with excellent handling but most of them seem to lack a bit in the power department. This example in for mapping had a supercharger fitted which makes it a very different kettle of fish. All was going well initially but then the engine started to develop a squeak. A quick look under the bonnet showed that we had a second “belt” wrapped round the front pulley. This actually turned out to be a section of the supercharger drive belt that had sheared off. The pulley was not aligned properly and had cut two sections off the five rib belt. Nothing much you can do in that situation without a spare belt so that needs sorting before the engine can be mapped properly.

OBD

I was interested to read in a recent issue of PPC about OBD code readers and the fact that you can use this OBD information for things other than fault reporting. We had a request from an I.T. specialist who was running our ECU and wanted to use an “App” on his phone that needed an OBD output. Basically you have to buy a little module that can be wired into the ECU plug and this then outputs the data from the ECU in an OBD form, either Wi-Fi or Bluetooth.

What you end up with is a series of dials on your mobile phone screen showing all the data that the ECU is looking at, engine rpm, air temp, water temp, throttle angle, etc. This is all very clever but to my mind of limited practical value. Then it gets tricky. You can buy a programme to use as a data logger on a track day. The ECU adds its information to the GPS in your phone (or Device as some call it) and you can record a lap showing cornering G, road speed, braking point, corner speed, throttle angle, engine rpm. I am sure there are plenty of systems out there but the one we bought to test the ECU software was called “Harry’s Lap Timer” and it gives you an awful lot of information for not much money. I am not suggesting this will replace a professional data logger but it’s certainly worth a look if you already have a fancy mobile phone that can run these “Apps”.

CCC Shed

Readers with good memories might recall the old Fiesta Mk2 that I used to race under the Cars & Car Conversions banner. It was known as “the Shed”. I put it up for sale here a year or so back and had a lot of enquiries but given that it was a non-runner nobody ended up buying it. Since then I have fitted throttle bodies, an ECU and mapped the engine here on the rolling road.

So here it is again for sale. Being realistic I am never going to track day or race it again so someone might want to take it on. The basic spec is a 1600 CVH (+60) engine with individual throttle bodies, K6 ECU; flat topped (forged) pistons, big valve head, lowered wet sump with windage tray, polished and lightened rods with uprated big end bolts. The gearbox is a synchromesh close ratio five speed unit. LEDA suspension, standard brakes but Magnesium alloy split rim wheels: £2500. If anyone is interested then call Emerald on 01953 889110.

Getting out and about

Not too long ago someone told me that I should get out more. Sitting in a room with fluorescent lighting and driving a car that’s going nowhere, day in and day out, isn’t good for your health. So I decided to take a day out. Where should I go? I know, I’ll visit Clive Atthowe in Norwich and take a look at his rolling road. Hey, it’s still a day out.

Clive and his two guys, Dan and Dan, operate a Dastek 4WD rolling road and specialise in diagnostics and re-mapping. They do a lot of Subaru engines and it was more than a little bit interesting to see Clive and Dan checking out a typical tuned Subaru Impreza STI.

The car had originally come in for a re-map having been fitted with a lot of bolt-on tuning bits including some new exhaust manifolds and an induction kit. Although the headline figure wasn’t far off what might be expected, the lower rpm range was pretty dire. Clive reckoned it was the new exhaust manifolds, typical eBay purchases, which were causing the problem. The owner went away and re-fitted the standard exhaust manifolds and then came back for a comparison. The stock manifolds, with the induction kit still fitted, transformed the engine. Taking a look at the boost curve pretty much told the whole story.

The new manifolds from eBay stopped the boost from building until the engine got to 6000 rpm and then there was a tiny increase over the stock manifolds. Look at the curves and you will see that the trade off wasn’t even worth starting to consider.

It was good to get out and talk to Clive about the problems of running a rolling road and various problems that you encounter in the day-to-day running or a business. His problems were pretty much a mirror image of the ones I come across on a regular basis, water leaks, oil leaks and bits dropping off. It’s nice to know that I am not the only one struggling from time to time to get it right.

I plan to visit Clive again soon with a more in-depth look at how he goes about mapping a Subaru WRX. Might even be next month if I can get another day pass from here.

The Vizard Lecture

For younger readers who don’t know the man, David Vizard is one of the biggest names in automotive journalism that has ever existed. David made his name here in the UK in the days when I still had dark hair and the misguided perception that I knew something about engines. To quote the man himself: “It’s not true that back it the day I used to drive chariots – I only used to work on them.”

David moved to the U.S.A and made a big impression over there in motoring magazines with his curious attitude that the best way to test things was to measure them. Then he would often go on to improve them using his Superflow engine dyno, everything backed up with solid dyno results, not just an opinion with the magazine’s editor keeping one eye on the advertising potential.

I recently attended David’s seminar in Swansea (see, I am getting out more) which was sponsored by PPC magazine. All attendees had to sign a non-disclosure agreement so sadly I can’t tell you much about the course or what I learnt from the various speakers – and I did pick up some really interesting information. What I can tell you is that my eyes were opened to the idea that two people can have totally opposing views and still both of them can be right!

One example of this is where you mount the injectors. Dave Mountain says they get good gains on their engines with outer injectors – most of the time. “It’s engine specific” was the way he described it to me. If you have only ever run a K Series on double injectors you would say that it doesn’t work and you would be right. But on other engines I have personally seen massive gains. The one thing I took away from the seminar was that there are not many hard and fast rules; you have to do the development and find out what works on your particular application. All in all a very interesting week-end and it proved to me that people are right – I should get out more!

Riley

I don’t often take on carb jobs these days unless it is something really interesting, like the Riley that was even older than I am. The engine was highly modified and sported triple SU carbs and a very interesting advance mechanism for the ignition. This was basically a lever on the steering wheel that moved the dizzy backwards and forwards.

You might regard this as very early computer-controlled ignition and in this case the computer is located between your ears. You have to look at the engine rpm and think about the load you are going to apply and then advance or retard the ignition accordingly. We set the ignition for maximum power and then altered the lever set up so that it could be advanced from there. Basically you advance on light throttle and then retard back to maximum power on full throttle.

Another feature was the gear change selector, again on the steering wheel (or very close to it). You select the gear you want, and then depress the clutch, and it changes gear for you. It’s called a pre-select gearbox and it certainly makes for an interesting drive until you get used to it. I would not say that the rolling road session was a total success but it made for an interesting afternoon and a change from the usual keyboard pressing routine.

Saker GT

I can’t say I am a big fan of the Subaru engine (see above) but I do love these Saker GT cars which use the Subaru engine. This one was a fairly routine mapping job but I thought you might like to see some pics of the car. It’s the nearest I will ever get to mapping a Le Mans car!

MGB

Regular readers might remember the MGB GT that had the gearbox ripped apart on the rollers. Well it made it back and happy to report that all went well this time round. One happy owner, and one happy rolling road operator.

K Midget

Another returnee was the MG midget that lacked full throttle. The answer was to replace the throttle pedal with one from another model that hangs down, rather than pivoting from the floor (see picture). This allows full throttle and after a few miles of loosening up, the engine is doing 200 bhp. I can remember back in the day when one lunatic put a 1500 pre-crossflow in a Frogeye and had 85 bhp. Everyone condemned him at the time saying that this sort of power in a Spridget chassis was just a step too far. How times have changed!

Missing Power

Not every car we run here makes the power that it is supposed to. I had an Elise in recently that was only making 170bhp in spite of having good compressions and correct cam timing. Everything checked out okay apart from the power – or lack of it. Sadly I have no magic wand so beyond checking the obvious there’s not much you can do as a rolling road operator.

It is even harder when you are trying to fault-find over the phone. The second Elise was making 177 bhp where the engine spec from DVA Power should have made more like 200bhp. After being assured that the cam timing was right and the compressions were good we began to suspect that the rolling road figure might have been overly pessimistic (the car was quick). The suspect Elise was booked in to coincide with an Event at Hethel test track and appeared early on a Monday morning.

The initial run showed 174 bhp on my rollers so there was nothing wrong with the original test. We started to look at doing a cylinder leakage test but then young Jono said that he hadn’t checked for full throttle yet. Sure enough, it was only opening about two thirds! It took a bit more than five minutes to adjust the throttle stop and the cable slack but eventually we had full throttle and straight away the engine made 192 bhp.

With Piper’s 1444 cams the torque was good at high rpm but I reckoned it could be better still. We fitted a set of adjustable parallel trumpets and then gained 17 ft lbs over the tapered trumpets and 12 bhp on peak power. Normally we see no peak power gain but I think we could have gained more torque at the expense of top end with longer extensions to the trumpets. However for a sprint car the set up looked good so we settled for that.

Herby

I can’t say I am a big fan of the Beetle but I can see why some people are. They make amazing drag racers because the engine is all hanging out the back with gives super traction on a RWD car. This example looks really tatty but under the bonnet is a super neat supercharged engine. The plan is to lacquer the existing bodywork so that the tatty exterior is maintained but it will not go rusty. Now that’s a plan I do approve of - I think they call them “rat cars”, where we used to call them “Q Cars” named after the disguised Q-boat warships of WWII which looked like harmless trawlers but were anything but.

Pick-up

Not into Beetles? Then how about a 1920’s pick-up truck? This one was powered by a Ford Zetec engine. While V8 engines used to be all the rage for this type of car more and more people are going the simpler 4 cylinder route as being a more practical power mode.

You get good fuel consumption and it’s much cheaper to install than a V8: makes sense to me. The thing I really loved about this car was watching young Jono trying to get behind the steering wheel – bugger all clearance between the wheel and the seat and there’s nothing much you can do about it except pull in your stomach and twist your legs into place on the pedals. I guess you either love this type of car or hate them, but I liked it – probably because it is even older than I am.

Honda F1

It has been a month of very unusual cars, from the pick-up and beetle above to this Honda F1 look-alike made by Stuart Taylor. The car is powered by a Chevy LS engine of six litres. Normally the F1-67 is fitted with four down-draught Webers but this example is a replica of the 1968 car and the carbs would not fit in under the bodywork. To get single seaters on the rollers we normally have to chock up the front wheels, but this car had enough ground clearance to drop pretty much straight in. We had a few of the usual first-running problems but it left here with enough power to be terrifying in a sub-600 kilo chassis that is geared for about 250 mph!

MKII Jaguar

I used to own a MKII many moons ago. I sold it for £350 which gives you an idea of just how long ago that was. Not the ideal car for central London though at 8 mpg!

This example cost a little more than £350 and would do a lot better than 8 mpg. The engine was fitted with the new Mangoletsi E-Type inlet manifold and Jenvey bodies. The inner wing had been shaped back to make room for some intake trumpets and I was told to feel free to experiment with intake lengths. The headline number was 220 bhp which might sound low for the engine spec but Jaguar’s official figures are now believed to be a bit optimistic to say the least. The E-Type is quoted as 265 bhp but we have never seen anything like that from an E-Type on our rollers. After mapping on the tapered trumpets I switched to the ALI (Adjustable Length Inlet) system and made the now familiar gains: 10 to 12 ft lbs torque increase across the mid-range and 1 bhp loss at the top end.

Mystery Misfire

The Honda S2000 in the Mallock we did a while back has been doing a lot of winning but suffered from an intermittent misfire. A Honda specialist had a go at it and decided it was something to do with the coil or the spark side of things. We messed about for ages on the rollers trying to duplicate the problem with mixed results. Then it dropped one cylinder after a power run and I was pretty depressed because I thought it was a mechanical failure.

It turned out to be just an HT lead that had fallen off the coil. Then on closer inspection we found that all the HT leads were a poor fit. To try to hold them in place, cable ties had been used but this had the effect of “squeezing” the boot and actually pulling the lead away from the contact. The resulting gap was causing interference as the spark jumped about 10mm to the lead. It was such an easy fix but a real nightmare to find. If that lead had not fallen off I think we would still be looking for the answer now.

Busa Turbo

I was told that I had mapped this car before but I don’t particularly remember it - but then my memory seems to get worse by the week. However, when it turned up I looked up the original power curve and it had been done seven years ago. Even after all that time the map was still pretty close, given that some small changes had been made to the set up. Now the car has changed hands and is used for sprints and Hill-climbs rather than track days. What I do remember is that the original expectation was for 350 bhp but it “only” made 285 bhp. The new owners reckon that 285 is more power than they can usefully put down on the hills so it was really just a question of re-mapping to make sure everything was till safe and sound. It was too.

Locost 1300cc

It was doing a few races in the 2CV cars that made me realise that more outright speed does not necessarily equal more fun. Yes, it is great to race a Caterham but it comes at a price – one that not all of us can afford to pay. But there are alternatives, like the 750 Club’s Locost series. I regularly do a few cars for Ian Gilmore at Procomp Engineering, that run in the Locost races.

The cars feature Ford 1300cc Crossflow engines with stock gearboxes and no diff. You could argue that it takes more skill to get a Locost to the front of the pack than a big money Caterham. I certainly remember following Mark Hales around Snetterton, he in a Locost with almost 90 bhp and me in a Seven with 160 bhp. I couldn’t stay with him once we got into traffic – just didn’t have his race-craft.

The car in the pics here is on a carb that Ivan spends hours preparing, plus a basic ignition with a dizzy. Nothing high-tech but it is the same for everyone and if you want to run at the front you still have to put in the effort on the rollers. It actually takes forever stopping the engine, changing jets, unlocking the dizzy and peering at timing marks, but that’s how it used to be before computers. I think I have just gotten lazy over the years. If you want to race a Seven type car on a budget this could be the series for you – but don’t run away with the idea that it’s easy or that you don’t have to put in the effort.

A Series Midget

Third time lucky! The midget in the pics finally came good on the turbo A Series engine after two false starts. The problem was the injector position. If you want a big power A series you either need a carb, or a throttle body that the engine thinks is a carb. See www.emeraldm3d.co.uk for the full story, I don’t want to bore you with it now.

K Series Midget

Another way to get even bigger power than a turbo in your Midget is to fit a K Series 1800 engine. I know it isn’t terribly traditional to have a 16 valve injected engine under the bonnet of a Spridget but it seems to make them go okay – as long as you uprate the rest of the car. This example had a bit of a schoolboy error in that it was impossible to get full throttle. There simply wasn’t the pedal travel available.

Rather than put off the mapping I made up a little hook from welding rod. Young Jono did the driving and I “applied” full throttle by hooking around the throttle lever and heaving it upwards. Jono gave me the nod at peak rpm and I let off the throttle as he dipped the clutch...yes I did lower the rev limit before we started!

DVA did the engine and he reckoned it would be good for 185 bhp. Typically for Dave Andrews it did a bit more than 190 bhp plus and it will gain as the engine loosens up with more mileage. We often see a 10 bhp gain after about 5000 miles or so of running. This does not alter the mapping, you are just making the engine loser with running in - the fuel and spark timing are not altered at all.

MGB

Some people are pretty nervous when they come here for mapping. The MGB owner was perhaps more nervous than most because this was his first engine conversion to his MGB, having fitted a Duratec engine and five speed gearbox. Personally I am always pretty relaxed, I have seen it all before and the problems are fixable 99% of the time.

We got down to mapping with the owner hopping from foot to foot, going out, coming back in and generally looking worried. “Stop worrying” I said, “nothing is going to go wrong” – and then it did. At about 110 mph there was a big bang and the room filled with smoke – never a good sign. Said owner ran out the room and collapsed against the wall, he was doubled over and I really thought he was going to be sick!

Up on the ramp the damage was clear. The cup with the propshaft needle rollers had fallen out (we found the spring clip later) and the resultant “whip” had pulled the back off the gearbox case off! It seems like the owner had been taking the shaft apart to use the front as a bung and (probably) hadn’t seated the spring clip properly. We stored the car for a few days until it could be recovered and the next time we see it I will keep my mouth shut about nothing major ever going wrong.

Big Bang

After nearly 20 years of running the rolling road I have finally worked out why we never have time for our own projects: it’s because we keep taking on other peoples projects. Already up to our ears in development, I let someone talk me into doing the Yamaha “big bang” engine. This is a weird piece of kit with the four cylinder crankshaft twisted though 90 degrees so that it runs a bit like two 90 degree V-Twins linked together. You never get two pistons at TDC at the same time, so wasted spark is not on. It has four coils that have to be fired sequentially and in the right phasing.

Basically the idea is that you get a few “bangs” and then the rear tyre is left alone to recover the grip, then another few bangs – and so on. The exhaust note is really weird but it seems to work in terms of traction on the track. This example is a grass track outfit, incredibly specialised frame and geometry – it certainly would not be possible to drive it on the road.

Exhausting test

One of the things I still desperately need to play with is exhaust pipe lengths and configurations. My experience is very limited in this area and I know there’s a lot to be gained (or lost) in the exhaust system and silencer department. We had a little play on the rollers recently with a 2.3 Duratec making 265 bhp but with a seriously noisy exhaust. Second silencer helped a lot with noise and lost very little power, but just in case we tested a “Decibel Killer” that simply slips into the tail pipe for track day use.

It certainly made the engine quieter but looking at the power curve we had lost 30 bhp! Most of this was at the top end of the curve, just where you don’t want to lose it on a track day outing. It is back to the drawing board on that one then.

Swansea Seminar

Somewhere in this issue I believe there is a big spread on the David Vizard seminar on engine building that is taking place at Swansea University. David has asked me to go along and give a talk on mapping so I am looking forward to meeting a few readers there and possibly exploding a few myths on mapping practice here in the aftermarket.

First off let me say a big thank-you to all the people who emailed and sent messages of the “get well soon” nature.  Much appreciated.  Now back to business.

1900K Elise

The K Series engine started life as an 1100cc design and became a 1400cc one by the time it went into production.  As history relates, it grew to 1600cc, then 1800cc which many people thought was a stretch too far.  One of the engineers working on the K Series production line explained to me that there was nothing basically wrong with the engine; it was just that the kit they were making it on was worn out.  If you can build it right the 1800K is a reliable engine.

Then along comes Mr Petrol-head and bores it out to 1900cc or even a full 2.0 litre.  The Elise I had in was fitted with a 1900cc conversion but it was not doing what the owner wanted.  He was looking for torque and therefore had stuck with Piper 285 cam profiles, rather than go for an all-out cam to make maximum BHP.  After sorting out the fuel and timing we had neither – not a great situation to be in when you have driven down to Norfolk from Scotland.

I suspected it might be the inlet trumpets and we had a couple of sets of tapered trumpets and two air boxes.  Of the two sets the longer ones were best but still disappointing.  Off came the top of the engine and we fitted up the cam timing dial gauges.  Cam timing was, in my opinion, way out so I set to and adjusted the lift on overlap to 3mm on the inlet and 2.5mm on the exhaust.  This has always worked for me in the past and I was pretty confident.

The result was a spectacular gain in torque and when we fitted the adjustable inlet system the peak torque was up to over 170 ft lbs.  It came out as 90ft/lbs per litre which is pretty impressive as road engines go.  By making small changes in inlet length we ended up with a compromise that still gave us good mid-range torque and a peak figure of almost 220 bhp.  After a day like that I am starting to think that I am a bit of a star at this engine set-up business!

1900K (again)

This time it was a Caterham that was getting the 1900K treatment.  But to go with the capacity increase we had a seriously big bore 4-1 exhaust, roller barrel throttles and massive 1444 Piper cams.  I will not bore you with the details but the result was again, not what we were looking for.  Out came the dial gauges and the cam timing was, in my opinion, way out.

After the previous day’s result I was really confident, after all, I am a bit of a star at this set-up business.  I set the cams to where I knew they should be – based on previous experience.  The result was...no different.  Looking at the waves in the torque curve I was fairly sure that the tract lengths were out but being a tapered system there was nothing I could do about it.  The engine still made 230 bhp but we were hoping for more.  I seemed to go from hero to zero in just one day – Perhaps I am not very good at this set-up business after all!

Rolling road hero

I was trying to help a guy with a V8 that was doing 3 mpg and had to have the sump emptied of fuel every few hundred miles!  Not terribly hard to diagnose when a car is over-fuelling by that much.  But the owner was sceptical because the engine had been mapped by an expert on a rolling road.

Eventually, after an engine re-build, it came here to Emerald and we did some basic checks.  The fuelling was off-scale on our mixture reader and the ignition timing was 40 degrees retarded on the reference.  The map looked pretty pathetic so we just started from scratch and got it right.  Even then it made some 50 bhp less than the previous rolling road had reported but drove a lot better and used a lot, lot, less fuel.

What really gave me the hump was that the rolling road hero in question was blaming the ECU and saying that he normally does MoTeC.   My point is that if he couldn’t even get the basics right on our ECU then what sort of job would he be doing with an ECU that was more complicated to set up?  Just having the kit does not make you a star!

1400K

It was something of a K-Series month and the little Metro was racing in a Metro series and doing okay.  The driver won his class last year but went into the gravel on the first race this year and damaged the engine.  It came here for mapping after an engine re-build.

The power was pretty poor and we did a basic compression test first.  Cylinders 2 and 3 were well down so we followed this up with a cylinder leakage test.  This test puts compressed air into the cylinder on compression and you measure how much air leaks out.  Trust me, 90 per cent leak is not good news.  A road engine will make 10 per cent all day and the best race engines can be as little as 4 per cent once run-in.

The car had to be racing that weekend so it was back to base for the car and some serious midnight oil was burnt.   Back it came with proper compression after the valves were all lapped in.  Just look at the results in the graph.  Night and day is the term that springs to mind.

Harry’s TR5 Again!

The first time I mapped Harry Dent’s TR5 it made 170 bhp and it was hand-shakes all round.  Then a month later it was all doom and gloom as the performance dropped off and the engine lost compression.  After a lot of faffing about it was discovered that the cam had worn out and the bits had gone around the engine, basically wearing everything out.  No idea where that camshaft came from but it wasn’t good news.

Harry removed the engine and stripped it out, rebuilding it with a Newman camshaft.  Back he came for mapping but the result was disappointing.  Harry had the fuel consumption and the smoothness he wanted but the power was way down on the first engine.  After a long conversation with Newman Cams they offered to replace the cam free of charge and had some ideas on what might give Harry the best of both worlds.

Back he came again and this time we had a hell of a result.  The peak power was 160 bhp but at lower revs than the first engine.  The mid range torque was way up on the previous engine so we did indeed have the best of both worlds.  Hats off to Newman Cams for the result and to Harry for not giving up.

Yet another Triumph TR6

We seem to have had a glut of Triumph TR six cylinder engines lately.  The latest one was a beautiful TR6 in stunning condition.  Cars like this always make me nervous because I am afraid to go near them for fear of leaving some mark on the paintwork.

I know some people are dead against updating these classics and think they should be kept totally original, but I can’t agree with that myself.  If we could only drive the cars in 1970 traffic conditions (and 1970s fuel prices would be nice) then there is an argument for keeping originality.  But we don’t.  We have to cope with current road conditions so more up-to-date tyres and brakes and engine improvement to help fuel economy are all perfectly acceptable in the world that I live in.

So here we have a TR6 with electronic injection and the original throttle bodies have been replaced with a single plenum type intake.  This is a neat way of doing it and much cheaper than six after-market throttle bodies. The problem with trying to keep the standard bodies is that you can’t get a throttle pot on the spindle as it has no extension.  The original linkage is a nightmare to balance and they tend to leak.  Not surprising given their age.

By going to a single modern throttle body you can also add an idle air control valve.  Now the bad news: If you fit any sort of performance camshaft to the engine you will get problems on light throttle and idle.  Just as you crack the throttle, as in traffic driving conditions, you get a snatch or jerk from the transmission.  This goes away as soon as you properly open the throttle but that’s not a normal driving style while creeping along in traffic at 1200/1500 rpm.

I have seen this problem on so many cars now, and I keep reporting it here in PPC, but nobody seems to believe me.  You cannot fit a performance camshaft with a plenum intake and expect it to drive nicely on light throttle.  That applies to any engine, not just six pot Triumphs.  There is a trick you can do with the mapping to try to alleviate the problem, which involves retarding the ignition to force the throttle open but you are trying to work around the problem rather than solve it.  Don’t say that I haven’t warned you!

Cam Timing

When fitting performance cams I am often asked to “swing” the cam timing on the rolling road to optimise them.  I don’t have a problem with this but it is always going to be at your own risk.  When an engine goes together, the builder really should mark the safe limits of the cam timing so that I can move the cams to find the best position without anything coming together.  If that hasn’t been done, then we are taking a big risk with clearance.

The Seven I had in recently had been here before when the Zetec engine had made over 190 bhp.  Now it had been rebuilt with modified bits and new cams.  The engine had been built professionally but the verniers were not marked and we had no instructions on how far we could safely swing the cams.  After mapping the first power runs were showing less than 140 bhp!

A call to the engine builder confirmed that the cams had just been installed against the original pulleys, rather than timed with a degree wheel or with lift at TDC.  Now we had a problem.  Half of the day had passed and we had no power and the owner had come quite a way for the mapping session.  We took the car off the rollers and pulled the cam cover off to check the timing with a dial gauge, measuring lift at TDC.

The exhaust valve had 50 thou lift at TDC which is what you would expect from a standard camshaft.  The inlet had no lift at all.  We had to remove the timing belt and shift the pulley two teeth to get 50 thou lift on the inlet.  How could it be so far out?  The answer is that the standard Zetec has variable cam timing on the inlet so if you use this to line up the new cam it is always going to be miles away from where the stock cam is with the engine running!

Once the timing was the same on both cams we had 210 bhp. There was probably more to come from more aggressive cam timing but without knowing how far we could go in terms of valve to piston clearance it had to be left at that.  Disaster averted but no thanks to the engine builder who should have known better.

A Series

The amazing thing about the little A Series engine is not that it makes such good power; it’s that it makes any power at all!  The shared intake port is a disaster for charge robbing where one cylinder sucks in all the mixture leaving the other one practically dry.   With a carb the mixture simply follows the air so although the cylinder filling is uneven the mixture ratio stays about right for both shared cylinders.

Once you try to fit fuel injection all that goes out the window. The fuel is added in a very short time period and no longer follows the air flow.  What you end up with is weak mixture on one pot and rich on the other.  Rover had a way around this by keeping the injection pulses the same time scale apart; one had a variable start time while the other had a variable finish time.  This works fine and Rover have a patent on it but there is still a problem in that you can only supply so much fuel before you hit a brick wall in terms of available injection time, which in turn limits the power you can have.

The answer, as I pointed out here some years ago, is to fit your throttle body in place of the carb and inject up-stream so that it works just like an electronic carb.  The A Series turbo you can see here had a slightly different problem.  After one false start the builder went away and fitted his throttle body up-steam, but on a fabricated plenum.  When I tried to map it we had major drama with the mixture.

As you opened the throttle the mixture went weak.  Add fuel and it suddenly went over-rich.  If you just sat there doing nothing the mixture would eventually come back to where it should be.  What I think was happening was that the fuel was building up in the plenum which had an off-set outlet to the engine.  Eventually it would find its way into the inlet manifold but the system just didn’t work.  The owner is now going to modify it with the throttle body directly to the manifold like a carb.

Internet experts

Regular readers will know that I am not a big fan of the internet but I do look at a few threads on various forums now and again.  One I liked was about intake lengths.  People were discussing the feature published here on inlet lengths and the adjustable system I came up with - If you missed it you can find it on www.emeraldm3d.com.

I did start to wonder if people think that I just sit here and make this stuff up!   I gave you all the results and included the test method yet there are still people out there who refuse to believe the results.  The problem is that they hold these beliefs based on what they have read, not what they have done or seen with their own eyes.  So here we go again this month, about to upset a few people who already know the answer to the question I have been asking myself for some time now.

Tapered vs Parallel Trumpets

Are tapered throttle bodies really better than parallel ones?

Take one Renault Clio Cup car and convert it from the stock intake to individual throttle bodies from Jenvey Dynamics.  These bodies are available with a parallel bore (45mm in this case) or tapered (48mm down to 43mm).   We ran the tapered bodies first and recorded the power and torque curves.  The intake trumpets were Jenvey 90mm tapered ones, their standard offering.  Next stage was to convert over to the parallel bodies on the same intake manifold and check that the overall length was the same as with the tapered bodies.  I should point out that with the tapered bodies there was a slight step it the manifold where the body didn’t exactly match the manifold port but then the match with the parallel bodies wasn’t perfect either; we live in the real world here and I was not about to spend hours porting and matching to gain half a horse power.  After re-mapping, the power curves were compared and found to be just about the same, plus or minus one BHP, basically the thickness of the line on the power curve and within the limits that the rolling road can measure.

The conclusion I came to was that the tapered bodies but do not work any differently to the parallel ones and you have to pay another £76 on a set of four to have the tapers.   The undeniable conclusion of all these throttle body tests is that it is the length that is the really important bit.   To prove the point we finally installed a set of our adjustable length inlets (ALI trumpets) and sticking them on full length gained torque right across the rev range from 3500rpm to 6500rpm.  In places this gain was nearly 10ft lbs, not an amount you can really argue with in terms of repeatability.  To be honest looking at the curve I would think that going even longer would be better still for mid-range torque but probably at the expense of a little top-end power; but that is just conjecture based on previous experience.

Bike bodies

Okay, I am not a great fan of bike body conversions for reasons I have gone into before in these pages.  But the V8 I had in gave me a new headache in that one body constantly spat back up the intake, even though the lambda was showing the right (average) mixture.  The balance was correct as far as I could tell but the spitting back could not be cured.  The injectors all flowed the same so the problem had to be an air leak; even though there was no obvious leak that I could see.

The answer turned out to be an interference one.   The very nicely made manifold was catching on the edge of the rocker cover and holding it off ever so slightly.   The result was an air leak - but only on that front cylinder, the rest were making enough contact to seal okay.  Sadly we couldn’t map the engine like that so the car was towed home to be sorted and mapped at a later date.  The moral of the story is if you have a body spitting back, it is almost always the result of a weak mixture.  If you get it just as you open the throttle then suspect the mapping first, and if it's not that, look at the throttle pot after that.  If the ECU doesn’t know that the throttle is opening (because of a faulty TPS) you will get a weak mixture hesitation or spit-back on initial opening.

Rotrex

I am seeing more and more Rotrex supercharged cars here and I actually quite like the system.  The theory might not be ideal in that the boost climbs with revs, rather than giving the traditional big mid-range torque boost you get from a conventional supercharger, yet the result in terms of drive and power output is very similar to a highly tuned aspirated engine.   This TVR probably didn’t need a supercharger but these days 500bhp has become the norm without which you can’t hold your head up in the pub.  Nice home-brewed conversion this one.

Another thread

One of the more interesting threads on Piston Heads has been pointed out to me by a couple of friends.  A regular contributor has been diagnosed with Non-Hodgkins Lymphoma.   The guys on the thread said that it was good that he didn’t try to hide it and they were generally supportive.  Basically he had developed a Cancer of the lymph system and I was particularly interested because I am in exactly the same boat myself.

As I sit here writing this I have no hair left and am going through the wringer a bit with the side effects of chemotherapy.  The reason I mention it is that if you turn up here and find me wearing a silly hat and not being in a very good mood, I'm blaming the disease, nothing to do with me turning into a grumpy old sod with little sense of humour left.   I find that having my life term somewhat under the microscope has made me a lot less tolerant.   For example, I was told by an engine builder the other day that my mapping had “bore washed” an engine on one cylinder while causing detonation on two others.  Nothing to do with shit machining or oval bores.   The experts involved are now putting in a rolling road so that these cars can be “mapped properly”.  The engine in question was never actually mapped at all because the injectors were too small and the mixture was going too weak at high rpm.  Bore wash – eye wash more like it.

Old School

It’s hard to believe but some people still call me up asking for advice on using carbs or throttle bodies.  Some “old school” engine builders are still insisting that carbs are the way to go and that you don’t need the complication of fuel injection.  Look, nobody sees carbs more affectionately than I do, but even through my rose tinted spectacles I can see their limitations.  The more power you try to squeeze from an engine the more the carb’s limitations show up.  You have a conflict of interests; small chokes to get a good signal over the main jet, big chokes to pass the air required for maximum power.  If you think about this long enough you will come up with the S.U. carburettor.  With a throttle body you can have a massive choke and it almost doesn’t matter.  You just squirt in the amount of fuel that's required and it finds its way into the engine.

A classic example was a Seven we had in fitted with a Raceline Zetec engine.  On carbs it had made 175 bhp and Raceline were expecting more power on the bodies, possibly 190 bhp.  To cut a long story short the engine made 200 bhp and with good manners to match.  The carbs had been too small at 40DCOE with 34 mm chokes but I hope you get the point.

First Injection experience

A friend of mine recently showed me a prized possession, something called a Wal Phillips Fuel Injector.  Oh wow, no need for rose tinted glasses, here was a piece of my youth, still vivid in my memory.  Wal Phillips had invented his “injector” for use on motorcycles.  His workshop was less than half a mile from my house so many years I went along to investigate.  To a 16 year old clueless apprentice it was a thing of wonder.  “Forget all you know about carburettors” said Mr Phillips.  This was easy since I knew bugger all about anything at the time.

I look at it now and I see a tap, linked to a butterfly.  It could not be any cruder but at the time I thought it was awesome and I soon parted with my £7 16 s 6d for a unit to fit to my Dad’s two-stroke 250 Ariel Arrow.   Within a couple of months I had melted several sets of pistons and then destroyed the crankshaft.  I could not be sure if the crank failure was due to the mixture constantly being out or if it was down to the “super wonder” two stroke oil that I started using. 

The super oil maker’s claim was that you could run it at half the normal mixture ratio thus leaving more room for petrol – which must then give more power.  God I was thick.  I believed everything that my perceived betters told me, a salesman’s dream.  Just think of how much trouble I could have gotten into if the internet had existed then!  Thanks Ivan, if you ever want to sell that Wal Phillips fuel injector...I have cash waiting.

Variable cam timing.

Just about every engine now has some sort of cam control on it, from cam profile switching like the Honda Vtec to actual variable pulleys or a combination of both.  The Toyota 2ZZ in the Elise has a cam switch to a second profile and a cam timing wheel that can vary the timing of the cam.  I ran one of these engines up when they first replaced the K Series.  On paper there is no comparison, 190 bhp against 118 bhp but when you compare the curves it starts to get interesting.

Up to 6000rpm the two engines deliver almost identical torque, then the cam switches over on the Toyota and you get a big “bump” up to 190 bhp.  Having installed a couple of ECUs and re-mapped the engines I was pleased to see a small gain over the stock ECU but I was following the original cam control strategy from Lotus.  Then I heard (bloody internet again) that if you varied the cam timing wheel from the original positions there were big power gains to be had.

On the Lotus it just moves the wheel from one end of the range to the other.  The range can go from zero to 47 degrees so keeping away from the stops we had it at 5 degrees on one end and 45 degrees at the other.  To cut a long story short with some new firmware we had the camshaft timing following our target map within a couple of degrees and no matter where we put it, the original Lotus setting was best.  Back off the timing at higher rpm and you can see the power drop away exactly in tune with the timing.   Internet bullshit yet again and since the information came from America I should have known better.

Linkages.

No month would be complete here if we didn’t have a few problems.  This time is was linkages that gave us the headaches.  The Rover V8 had a twin plenum intake which, I am told, is pretty rare.  The problem was that it had a flat spot off idle that mapping would not sort out.  Been here before, look at the throttle pot numbers and see how they do not alter with initial butterfly opening.  In this case the twin intakes had a carb type linkage between them with the cable pulling from one end and the pot on the other.  The spring tension had to be taken up before the pot moved with initial opening of the throttle from the cable end.  I just screwed the adjuster up tight and the problem went away.

The second one was more complicated even though it was a straight forward GBS kit car with a stock Zetec 170 engine on bodies.  The idle was lumpy as hell and since a quick look at the mixture didn’t help it was obvious that the bodies were out of balance.  No problem, the Jenvey linkage is pretty straight forward and I have some bent up Allen keys to get at what I need to.  Now take a look at the pictures.  Somebody (no the people with the car) had gone to great lengths to cock it up royally!  The linkage had somehow been fitted to one end of the bodies (the wrong end) and a bridging piece had been fabricated and pinned between the two main shafts.  The original, correct, linkage had to be dismantled to do this!  The only word I can find to sum this up is: “insane”.  It could not be mapped as it was and we couldn’t find the right linkages in stock.  The car had to go away for sorting out and come back some days later for mapping. 173 bhp: pretty good for a brand new, tight, engine.

Carbon Puma.

I have seen this car before but not with the newly built turbo Cosworth with eight injectors.  Unlike most applications where you have upper and lower injectors, these ones are fitted side by side.  Both injectors are the same flow rate so the idea is to use four for light throttle running and then eight when you need the fuel flow to make the power.  And that’s exactly how it worked out.  If you are looking for some custom made carbon panels contact NUR Motorsport on 0118 9594 866 and speak to Noel.

Lambo with Lambo power!

I have done a few Lambo look-alike kit cars here, mostly with BMW V12 engines and they really do look and sound the part. So when I had a Lamborghini booked in for a power run I was curious to know what engine I was looking at, probably BMW.

When the car turned up it had a Lamborghini engine; because it was a genuine Lamborghini Countach! As the car was backed into the rolling road cell you had to be impressed with the reversing technique. I had heard about the driver sitting on the sill but had never seen it before. On the rollers the mixture proved to be a bit rich but not bad for carbs. Power was almost what the factory originally claimed too, well over 400 bhp.

Misfires.

Why is it that when people get an engine misfire they immediately start looking for the most complicated reason possible - human nature perhaps? In the instance I am referring to the problem was one of interference with the engine management system, but solely due to one of the spark plugs having been cracked by clumsy installation. Always look at the spark plugs before you do anything else.

When I have a problem I always start by pulling one plug lead off at a time and checking the engine note.  All you need are some insulated pliers.  Having found the suspect cylinder hold the lead near the plug and check that you can hear, or see, it sparking.  That eliminates the ignition side of things.   Put the plug lead back and then pull of that cylinder’s injector plug.  Put a little test light across the injector terminals.  This is a simple little led.  You can’t use a light bulb because the current pulse is too short to cause it to glow.  If the led flashes then suspect the injector.

I use a starter spray like Easy-start and pump that into the offending cylinder (or common intake if you have no option).  If the cylinder fires up then you know that you have a fuelling problem.  If the led doesn’t flash then start looking at your wiring.  You don’t need much by way of special kit to track down misfires.  A simple timing light can be used to check that the spark is not going out under load.  Shine the light into a dark corner and apply engine load.  You will soon see if the flash is not steady indicating some missed spark events.   People tell me that this trick can only be used on cars with HT leads, not coil-on-plug engines.  Rubbish, remove the coil but leave it connected to its plug.  I keep a short length of HT lead and simply fit that on the spark plug and push the other end up inside the coil.  Now you coil-on-plug coil is a conventional coil with an HT lead to connect to your timing light.

Most, if not all, ECUs now have some sort of logging system inbuilt.  If that all shows up okay you can pretty much eliminate the ECU side of things.  Remember that if the trace is showing okay on the datalogger screen or trace it means the ECU thinks that everything is working.  For example just because the trace is present on the injector signal line it doesn’t mean that the injector is working, it may be seized and the ECU will not know that.

Trends.

You would hardly call me “trendy” but I do often spot trends in the tuning industry, mainly from the number of cars that pass through my doors.  One trend I am seeing at the moment is engine swaps. Rather than tune an existing power unit, more and more people are just fitting a larger, stock, engine. A classic example is the E36 BMW 3 series that I had in, fitted with a later BMW V8 engine: big lazy power right under your right foot.  You get factory stock reliability and fuel consumption.  If you are building a road or track day car it’s a nice way to go.  Lotus Elise S1 models keep turning up with Honda or VW power transplants, sometimes supercharged, often turbocharged.

Just about anything that used to run a Rover V8 now appears with the Chevy LS engine, a lovely conversion because you get a big capacity hike in a more modern package.  The stock LS1 in 5.7 litre form will make just about 400 bhp all day long.  That will make your TVR hustle along and if that’s not quick enough you can fit any number of tuning parts from the U.S.A or go up to 7.0 litres for some serious chassis twisting torque.

Internet.

I don’t want to sound like a broken record but it’s the internet – again.

Anyone, and I do mean anyone, can re-invent themselves overnight into anything they want to be.  Sadly that does not mean they can always live up to the hype. “This engine builder is amazing”.  How often have I heard that?  There’s nothing “amazing” about building an engine.  You just bolt the bits together.  It’s the bits that you use and the tolerances in the bits that you use that make all the difference.  A good engine builder will be able to look at a component and decide if it can be used again or if it needs replacing.  He knows what cam to use with what engine spec; he will also know where to set the cam timing.  Engine building is really a question of experience and that does not come overnight.  Obviously you need to be competent with spanners, torque wrenches and, when called for, a hammer.  But it’s not a skilled job like panel beating or welding.  Some people have a gift for that sort of thing; you do not get gifted engine builders.

Take a look at the picture of the wide band Lambda sensor.  It has been “fitted” by gripping the body with a pair of pliers.  You probably can’t believe that it still works – and you are right not to because it didn’t.  So where is this leading?  It’s leading right to a new and “amazing” engine builder.  Quote: “He’s better than John Eales.”   What is John Eales doing wrong with the Rover V8 that this guy is getting right?  I would settle for being as good as John Eales except I have never built a Rover V8 engine in my life.

I can’t go into any detail here because there could be legal action involved, but during the recrimination, finger pointing and blame period that always seems to follow an internet thread, I came across some good guys.  David Harvey of SC Power came to my workshop to check out the installation of their supercharger conversion kit on a Rover V8 engine TVR.  He wasn’t happy with it and spent the next nine hours pulling it apart, replacing some components and re-building the whole kit.  He did all this free of charge.  His main concern was protecting his reputation.  Since we were checking out the ECU installation for similar reasons (also free of charge) I know exactly where he was coming from. So, if you are in the market for a supercharger conversion I can recommend SC Power as some of the good guys – but don’t expect them to do it all for nothing, it’s supposed to be a business after all.  SC Power: 01277 225000.

Grumpy Old Man.

It’s official! I am now a fully paid up member of the grumpy old man club.  I had my 65th birthday last month and I am now a pensioner.   Now I can complain about everything, I’ve paid my dues and I have earned it.

So, first grump this month is about wiring (yes again).  People will spend thousands of pounds on building a superb engine and then save a couple of quid on the wiring loom.  The stupidity of it beggars belief.  The life of the engine is hanging off those few critical wires.  This car came in after the first engine had melted and now it was my turn to try and sort it out.

First off there was a strange intermittent ticking noise coming from the engine bay with the ignition on but the engine not running.   Looking at the live mapping screen the rpm reading was flicking up to 80 or 90 rpm and back to zero.  What I could hear was the coils firing off because the ECU was being told that the engine was turning over (when it obviously wasn’t).  A quick look at the crank sensor wiring showed that it was not shielded wire and there were some very dodgy looking joins on the loom.  My guess was that one of the ECU PWM (pulse width modulated) signals was showing up in the crank trigger wiring.  The easy test was to make up a shielded wire and run that around the engine and into the ECU.  Problem solved, now on to the mapping.

Except now I had no MAP sensor reading.  You can see the bodge job on the MAP sensor wires for yourself.  We fitted a new plug and made proper connections further down the loom – some people have yet to discover heat shrink it seems.   A quick check on the boost solenoid showed that this was not working.   The car was purported to have been previously mapped to 1.5 bar of boost so it must have worked at some time.  Investigation (yes, wiring again) showed that the solenoid was wired to the wrong pin in the ECU – suggesting that it had actually never worked at all.   That was an easy fix, just move the pin to the right hole and it worked fine.   Then finally the idle air valve wasn’t working properly but that was just a wrong setting the ECU software.

So the engine was finally mapped and it worked okay.  I did hear that the people who did this installation originally wired it up for a different ECU, only to find that the chosen ECU did not do five cylinder engines!  My real bitch here (now that I am officially grumpy) is that if you set yourself up as an expert and take money from people for doing a job – you really should be up to the task.

Good News.

And now for some good news: for K Series engine owners.  I see quite a few K Series engines here and cars like the Rover 200/25 are very popular in grass roots Rallying where the motors have to remain pretty stock.  But in a series where you can run any original part there’s a new trick recently come to light.   A Rover specialist who uses us measured up a lot of standard Rover cams and discovered that the VVC exhaust cam is a bit hotter than the standard Rover offering.  He fitted two VVC exhaust cams to his 1600 K Series and came up to have the car mapped.  Owen from The Rover Centre is no fool; he brought a pair of stock cams with him to do a quick-change operation if it all turned to the brown stuff.   Happily this wasn’t needed.   We gained nearly 20 bhp over the stock 1600cc engine which is pretty good when the rest of the motor was totally standard.   Idle and light throttle drive were perfectly acceptable too.   If you happen to have a few of these cams lying around it’s a good cheap route to extra power.

Hanger 111 Supercharged Elise.

Hanger 111 is a Lotus tuning company who recently purchased the rights to the Turbo Technics Elise supercharger conversion.  Greg at Hanger 111 spent some time converting the system over to the current Rotrex blower unit which runs a separate traction fluid lubrication system whereas TT used the engine’s oil supply.   We had the first one in for mapping recently.   The car would have made about 230 bhp on the original TT blower so it would be an interesting comparison with the later Rotrex unit.  Being old and grumpy (see start of feature) I wasn’t expecting much but the result exceeded all expectations.  260 bhp is really impressive and there’s a fair dollop of torque to be had too.  The result is one quick road car that isn’t minus all the civilised road manners either.

Older Lotus.

Just feast your eyes on the Lotus 520 shown here.  Colin Chapman’s idea of a family car wasn’t exactly a Ford Cortina.  Cars like this immaculate restoration frighten me to death; I am scared to touch them in case I do some damage of mark the interior.  When you look at the standard of workmanship in this restoration I start to wonder if you can take things too far.  Personally I would be scared to use this car; it’s almost too good...or is it just me?  Either way, enjoy.

Our RX7.

A few people have been asking how we are getting on with our RX7 V8 conversion.  The answer is: slowly.  Part of the problem we had was that the turbos fitted in nicely exactly where they were, but that meant a slight restriction to the intake pipes.  The chassis was half obscuring the rubber inlet pipe.  Personally I did not see this as much of a problem; the engine would already make more power than could be used by any sane driver.  However, I am only half the team on this conversion and the other half is a bit of a perfectionist so the chassis had to be modified.   Being a great believer in letting people who are better than me get on with it, we enlisted some help from one the guys working at Turbo Technics.   Young Tim (everyone is younger than me now) gave up his Sunday to come over to Norfolk and cut out the chassis, then weld in some strengthening plates to put the meat back into the car.  It took forever with Tim working well into the dark hours.   Really neat job and another major step towards breaking the diff, the drive shafts, and shredding the tyres!  Cheers Tim, we owe you!

Trumpets.

The response to our adjustable trumpets (ALI's) has been amusing to watch on the internet.   There are people out there still worrying themselves to death over a tiny step in the inlet pipe.  What they can’t get their heads around is the results.   I think I have been around long enough for people to believe that I do not make things up.   The results show massive gains, or losses, with a change of inlet length and not once have I seen a tapered trumpet give a better result than the parallel system.  The step makes no difference and I have proved it on the flow bench and the dyno, but still they don’t believe it.

The potential gains from finding the right length are huge; the losses from the step are immeasurable but still, like a dog with a bone, they can’t let it go.  We tried these trumpets on a full race, full Monty, K Series engine.   The original trumpets were 50mm with massive intake area where the trumpet tapers outwards.  Putting on some 45mm adjustable trumpets gave a good gain in mid range torque with only a small drop in peak power.  The answer will probably end up as parallel 50mm trumpets.   As the engine builder said at the time: “we used to have parallel trumpets on Weber and Dellorto carbs, what has really changed since then?

Taster/teaser.

Let me finish this month with a brief mention of some testing I have been doing on cam timing.   We have been tasked with sorting out the ECU needs of a Toyota engine which has variable cam timing on both the inlet and exhaust valves.  Looking at the available duration it seemed to me that we could get all the right idle and light throttle running from having no lift on overlap, then get a big power gain from pulling the cams in and getting some proper overlap.  That has been my experience with performance cams in the past.  But this engine has stock cams and I was in for a rude awakening.

The engine makes best power with almost no overlap and when you pull the cams together the power disappears!   It seems like Toyota use the inlet cam for power but use the exhaust cam to back-feed the exhaust gas as a form of EGR (exhaust gas recirculation) without all the valves and pipe work seen on a conventional EGR system.   Tricky stuff but the question is; will we be able to use this system with a proper inlet and exhaust to get the best of both worlds from a hotter cam set up?  Watch this space!

Monster Jaguar.

Take a look at the pics above before you read on.  This Jaguar XJ started out as a full-on race conversion but got sold on when the builder ran out of money.  Now it is a really amazing track day/road car.  It was driven to us for mapping by keeping the revs and the load down to a minimum to avoid any possibility of damage to the supercharged engine.  In a way it is a pity that the owner was so careful; part way through the mapping I seemed to be getting wheel spin.  Power at the wheels was only 90 bhp and the boost was minimal.  Straight away that rings some warning bells.  If the Speedo is working and driven from the rear wheels then the road speed on the clock should go up as the wheels spin.  In this case it didn’t.

The problem was that the clutch was slipping.  I checked the fluid which was a tad over-filled but pulling some fluid out made no difference.   Sadly on this occasion the car went home just as slowly as it arrived.   Having said that, at least it will live to fight another day.

Duratec disaster

People often ask me how many engines blow up on the rollers.   To be honest we have had very few failures in the last 16 years that I have been mapping engines.  The Elise I was doing was fitted with a 2.0 Duratec conversion.   Basically the Ford engine is mated to the original Rover/Lotus gearbox with an adapter plate.  I have seen 275 bhp from a good engine in these cars and they are super fast on the track.

This example had been trailered from Germany for mapping.   That’s some 1200 Kilometres door-to-door.   Everything was going swimmingly and we had good power up to 7300rpm where I had set the rev limiter.  The owner reckoned 7500rpm would be no problem and since the power was still going up I increased the rev limit to 7500rpm.  You are probably ahead of me...the first run to 7500rpm resulted in a crunching noise and a sick engine.

When I tried to turn the motor over it jammed up around TDC.   Out came number one plug and it was a mess, really beaten up with mechanical damage.  The other three were fine.   I had a fish around down the plug hole with a magnet-on-a-stick and came up with two curious bits of debris.  Obviously magnetic, I had two fragments about 5mm deep and slightly circular.   If I put them end to end they looked to form a circle about the size of an inlet valve.

Then the penny dropped, it was the inlet valve seat insert I was looking at.   When the head was lifted (back in Germany) this was confirmed.   The head seems to have been ported and the said insert left so thin that at high rpm it simply fell out of the head.  As you can imagine, it was a mess.   The fact that the other three cylinders were spot-on tells you that it wasn’t a case of the valves hitting anything first, otherwise all of the cylinders would have suffered.

Interesting misfire

I had a Capri V8 to do and it was a nice one – full-on throttle body conversion.   I was mapping only for a couple of minutes and I ran into a problem.   If I had the mixture right you only had to crack the throttle open slightly to get a weak-mixture misfire back up the throttle body.  Usually this is a question of the throttle pot lagging behind the butterfly (free play in the drive) but this wasn’t the case here.  I have to admit I was scratching my head for a bit.   Then I spotted the throttle linkage.  The central tower was offset and that meant that the linkage had a different ratio on each bank.   The bank with the throttle pot opened slower than the second bank.  Hence the second bank went weak as the throttle opened unless you made the first bank with the pot attached too rich.

We managed to tweak the linkage to get it much closer to even opening and that pretty much solved the problem.   I see dodgy linkages all the time, especially on bike body conversion and it can give some nightmare mapping problems.   If you are not going to fork out for a decent linkage kit please take some trouble over making your own – it’s more important than you might at first think.

Another head scratcher.

On low boost the engine ran fine but when you flipped the switch to the maximum attack boost map the engine surged forward, then slowed down and surged forward again.   It went up the road in a series of leaps – not the ideal situation.  The guys tried in vain to find the fault and with a car like this you can’t really test it in the middle of town.  Jim asked me to take a look at it on the rollers.

Looking at the log of the boost it was obvious what was happening.  The boost was surging so the first port of call was to try to eliminate anything mechanical.   It was fine on low boost but as you adjusted it upwards it started to take on a mind of its own.   I put a mechanical boost bleed valve in place of the electronic N75 valve and tried that.   It worked fine.  We tried a new 12volt feed to the valve, we tried a new valve, we ran wires directly back to the ECU, but nothing would do the trick.   I spent all day messing about trying everything I could think of and all to no avail.   I said to Jim that when we did find it, it was going to be something simple, it always is.

For want of something better to do I pulled the spark plugs out.   Hello, hello, what this then?  No resistor plugs, just plain grade 8 competition plugs.  You MUST always run resistor plugs with any engine management.   But, they argued, they were the same plugs as before.  How about the HT leads?  The leads looked the part, really thick and colour coded to the hoses, they looked as fast as a fast thing.  But when I did a resistance check they only showed 0.7 K Ohms.  Proper resistor leads should be about 12.0 K Ohms at that length of lead.  That was the answer; the problem only appeared after the new leads had been fitted.

We put in a set of grade 7 resistor plugs and the problem disappeared!  Some days are like that, all day messing about for the want of six spark plugs.  The leads were basically crap for all their thick insulation and bright blue colouring.   I knew it would be a simple fix when we found it; it always is, but that one was a bit of a choker.

Adjustable Length Intakes (ALI)

I will not bore you with it here because Will is publishing a bigger story elsewhere in the magazine; but I have done even more testing on intakes using 42mm ALI sets for the K Series engine.   Results are pretty impressive but you have to look at the overall picture.

The power graph shows the same length ALI set up but one with foam filters and the other with a closed air box.  The numbers speak for themselves!

However, on the Datsun 260Z featured recently we had the opposite result, with the air box we gained power.   It’s very much a case of suck-it-and see.  Llike people, every engine is different.

Rose tinted glasses.

It’s been a few years since I built a Pinto engine, well a few decades actually, and these days I can’t help thinking you would be better off with a Zetec engine.  But the Mk 2 Escort I was looking at had a 2.2 Pinto engine and the owner wanted it that way because that’s the engine it was supposed to have.  It did look right I must admit.

The target power was 180 bhp and that’s a lot from a road going Pinto.  My fast road 2.0 litre engines used to make 165bhp with a sensible spread of torque.  Full race 2.1 engines made 215 bhp at best.  However this engine had a stroked crank with Fiesta diesel rods and a bigger bore to give it 2.2 litres.

The first power run on full throttle showed 178 bhp which was a pleasant surprise and that meant we could start trying a few things to get the best from the engine without worrying about headline numbers.  After sorting the fuel and ignition timing we were looking at a very creditable 192 bhp with 153 ft lbs of torque.

The next step was to try a different intake trumpet length.  Needless to say I dug out some of my adjustable trumpets, even though on this throttle body you could not slide them into the body – the body was just far too short.  Initially we had three trumpets long and one shorter to clear the battery tray. After some promising initial results we took the plunge and cut the battery tray to clear number one cylinder’s trumpet.  The difference over the original tapered trumpets was well worth the effort, 197 bhp from a pretty flexible road engine is very impressive.   What’s more the torque had climbed to 164.6 ft lbs.  More often than not, when you look back in time, you tend to see things through rose tinted glasses but in this case the old Pinto really can still be made to do the business.  Hat’s off to Graham Bhar who built the engine.

Mini A Series

Staying with the historic theme this stunning Mini has a 1445cc A Series engine with all the right race bits inside it.  The owner didn’t want anything other than traditional Mini engine bits so you want find any sixteen valve heads or five speed boxes on this one.   What you will find is a stunning ground up restoration with a lot of custom parts and modifications.  The clutch slave cylinder is one example.  A race clutch tends to bust the original seal so a Golf cylinder has been grafted onto the Mini housing.

The throttle body is also “interesting”.  It was robbed from a Volvo and fitted onto the original Mini log inlet manifold.  Two injectors squirt into the plenum area underneath the butterfly.  The other two injectors in the original positions do not do anything.

I have to say the idle was rough as a bear’s bottom but 106 bhp can’t be all bad news.  It was a pig to map too but we got there with it.  I have to say how much I admire some people’s commitment to a project.  From a bucket of rust to this standard in 12 months (and £17,000) yet to look at it you would not think it was anything other than a very tidy 1967 Mini.

Endurance Lotus

Paul Goldring runs a somewhat legendary Lotus S1 - these days mainly in Endurance events.  The car ran at Dubai for 24 hrs with just a couple of wheel bearing problems and some contact damage but finished right up there with much faster cars.  I know it had very little power because I had mapped it prior to the event.

Now the car was back with a fresh engine (still pretty much stock) as it was being prepared for the Barcelona 24 Hr race.   The trick with this type of racing is not pure speed, it is to keep going.  Essex Sports Cars who prep the car have modified it to take the S2 wheel bearings and fitted a much larger fuel tank.  It still has limited power but can probably run for 2 hours at a time.   I had the car back in here for another last minute check and then it was off to sunny Spain.   You always need an element of luck in any form of racing but I would not be too surprised to see the car do well again.  Fingers crossed!

V12 XJS

I have to confess this is not my favourite car or engine for that matter but this example was in rather good nick.  It is going to be the subject of an editorial in a Jaguar specialist magazine so it was nice to see them doing it properly with a base run prior to engine mods.  Sadly it had an auto box so I did struggle a bit to get a decent curve.  The problem with any auto box is that it does have a habit of changing gear part way through a power run.   With the help of some extrapolation software we managed to get a curve but, as always, the power figure was a bit of a disappointment.   I often joke with people that part of my job is engine mapping while the other part is grief counselling.  Some days that joke isn’t so funny!

Big Z

We all know that sports cars should be red but this 260Z was such a gorgeous candy red I couldn’t take my eyes off it.  The finish was truly stunning and the power wasn’t bad either.  Playing with the adjustable trumpets in place of the carbon ones we had a decent gain but as with Steve Kiddell’s 240Z it works much better with the air box on, rather than off.  Never mind the power or the build quality, just look at the picture and admire at the lines and the paintwork finish.

Lambo Doors

I know a lot of people (Will included) don’t like Lambo doors but you have to admit they look sort of right on a Lamborghini.  This replica had a V12 BMW engine and was running pretty sickly.   As delivered it made 200 bhp at max rpm, pretty sick when it should have made 300 bhp at stock.  The trouble with this type of engine is that you can never tell how many cylinders they are running on.  With one or two cylinders missing the resulting V10 is still pretty smooth.  To add to my troubles there was nowhere to put a lambda sensor and I was trying to set the mixture initially on power output alone.  I used to do it this way about 20 years ago but things have moved on.  I am mapping in the dark without my sensors.

Pulling off the injector plugs gave me a suspicion that the engine wasn’t firing on all 12 pots so the plugs came out of inspection.   That killed about an hour!   Sure enough several were not firing so a new set went in.  Next with the engine firing on all 12 pots the mixture was so weak it would hardly run the engine.   If someone had been trying to map it with some cylinders pumping fresh air into the exhaust it confuses the lambda (and often the dyno operator) no end.  Working blind I had it up to 302 bhp before we ran out of time.  The car will be back with some lambda bosses in the exhaust and then it should be a straight forward mapping job.

Changing times.

I had a call recently from a very good rolling road operator who asked me to stop recommending him to people with systems to map.  It was nothing personal; he reckons he has just had enough of it. Water leaks, oil leaks, pipes blowing off, constant complaining about the results, dodgy wiring and cheap Chinese components and the like have just worn him down.  He’s giving up the rolling road to do more regular servicing. It’s a lot less hassle and relatively easy money.

 I can’t say I blame him because over the years I have given away a fortune in lost time though no fault of my own.  If a car turns up and has a total failure I usually just say:”go away and fix it and we will sort the mapping next time”.  I have had that happen three times in a week and then you look at the books and realise that you still have to pay the rent, rates, and utility bills.  I can’t stay afloat by feeling sorry for people and my mate has come to the same conclusion.  He has given up; I am having a change of heart.  From now on if you can’t complete a mapping session because something has gone wrong with the car I am going to ask you to pay half the mapping costs.  We can share the pain but I can no longer bear all of it.  It’s either that or I take up car servicing!

2CV Champion x 2

I do a few 2CV set ups for a few people who helped me get into the 24 hr race back in ‘05 and we have pretty much stayed in touch.  So just a brief mention for young Sam (Samantha) who has just won the 2CV championship for the second time running.  Sam not only drives but builds a mean 2CV race engine too.  Congratulations on the back-to-back championships Sam, nice of all the blokes to do the gentlemanly thing and let you win!

Young Jono

Congrats also go to the sorcerer’s apprentice young Jono.  He did his first solo mapping job recently, a Caterham on throttle bodies.  John might look young but he has nearly five years under his belt now at Emerald and he is really starting to get the hang of it.

Fast 240Z

Steve Kiddell is no stranger to these pages and his 240 Z Datsun just goes from strength to strength.  Basically it is an all steel 3.0 litre with all the goodies.  Those goodies used to include some expensive carbon trumpets but after a bit of tinkering Steve decided to sell them on and try my new adjustable intake system.  I was not convinced that it would be any better but Steve had more faith.  We made some serious gains and now Steve’s engine is arguably the best 240 Z in the UK. It is certainly the fastest.  Almost, but not quite, 300 bhp.  Finding 100 bhp per litre from a two valve engine is not easy and it has taken a few years but Steve is finally there.  With pretty much nowhere else to go the sensible thing would be to stop there and enjoy the car.  Not Steve though, Nitrous Oxide is next on the shopping list!

Beetle Bother

Not really my cup of tea but I know that the VW Beetle has a massive following.  This example belongs to a Beetle Bodywork restorer and at the moment it is “as found”.  The engine isn’t though.  That’s a big bore job complete with a supercharger from a Merc.  When it came in it was firing on one cylinder and looking at the spark plug access I was already praying that the plugs did not need to come out.

They didn’t and after some tinkering with the configuration files it was running on four – but making a hell of a din.  Turns out that the supercharger was making boost on idle and the drive was complaining.  The system needs a recirculation valve or at least a blow off valve of some sort. I am sure it will be good when it’s sorted.

Big Nissan V6

V6 Engines are really nice to map because they are as smooth as a V8 but without making over-the-top power.  Well that is usually the case but this one was an exception.  Twin turbos and one bar of boost produced around the 500 bhp mark.   It was especially pleasing for me because this was the first V6 Nissan that was running the stock trigger disc.  This has 360 slots photo-etched into a sliver thin foil disc.

The disc runs at half engine speed and has six more slots on a smaller base circle.  If you want to know why the Japanese have gone this route, rather than a simple crank trigger – you will have to ask them as I have no idea!

Clio Racer

I don’t know how I get talked into these jobs but we recently took on a Clio racer.  Karl here had to write the software to read the silly Renault 60-1-1 trigger pattern and we had to get someone in to make up a loom.  It was all a mad rush job and I had agreed to fit a cable throttle body for the owner.  Four bolts, hardly much of a challenge.

When the bits arrived the stud pattern did not match the manifold.  I had to plug the original holes and then bore new tapped holes for the new body.  Then I had to make up a bracket to hold the cable outer.  The bracket consisted of a bit of angle iron that used to support a bench in the workshop.  I have lost count of how many times I have used a bit of our old bench, I am going to miss it when the supply finally runs out – might even have to buy some metal in.  Two late nights and we had the engine mapped in at 210 bhp.  Not really what was wanted but we made it in time for the first race.

VUU

If you read that number plate it says: “Vee Double U” get it?  I first mapped this car four years ago and I remember it because I had a bit of “finger trouble” with it.  I sent the car out with one digit missing from the map.  I blame the keyboard but the result was a flat spot just off idle.  I found it straight away but that taught me to check and double check before I let anything out of the rolling road cell.  Funny that you tend to remember your failures more than your success...

Dave gets sent to Coventry...

It’s not often that I manage to escape my rolling road cell but this month I had a day out at TVR power near Coventry.  The purpose of the visit was to try to get a better map for Craig Taylor’s twin turbo V8 RX7.  TVR Power has a Dynojet rolling road that basically consists of a one ton single roller set in the floor with a dyno on the end of the shaft.  This means you can hold load or do accurate acceleration runs - almost without any power limit.

I arrived late (living in Norfolk you forget what a traffic jam is) and the car was already strapped down and waiting to go.  After a bit of a delay finding a suitable lap top I began doing a bit of mapping on part throttle.  Initially the wheel spin was insane but that was because someone had put some big numbers in the boost control map and we were seeing 20 psi of boost!

I cleared the boost map and tried again.  The original springs in the waste gates had been replaced with very light 4 psi springs so the boost was quite controllable.  I managed to get a few power runs and once I was happy with the timing and fuelling I started to try to wind up the boost a bit.  The level of grip available from the big single roller was impressive but the completely alien set up took some getting used to.  I am indebted to Jason Oakley for operating the rollers so that I could concentrate on the map.  Jason gave me a head-set with microphone so that we could talk to each other above the noise of the cell.  I told him that I felt like Madonna with this microphone kit on and he replied that I didn’t look like her!

All was going swimmingly until we got to one bar of boost when the engine started to misfire.  The problem was that the boost was putting the spark out.  Craig was still on the running-in plugs, standard with really big gaps intended to fire up weak mixtures – not exactly what we needed.  Even though the engine was misfiring we still recorded an impressive 804 bhp at the driving wheels.

Craig reports that the car has better fuel consumption now than when it was a 7.0 litre aspirated engine and it’s pretty fast.  Apparently you can cruise on the motorway and just by squeezing the throttle you can leave two black lines down the middle lane!  We are now inspired to get our own twin turbo V8 going but we will have to do something about the current diff if we want to run the planned 1200 bhp.

Harry’s TR5

A while back I wrote about Harry Dent’s TR5 conversion.  This was basically junking the old Lucas mechanical injection and going electronic.  After 400 trouble-free miles it all started to go wrong.  There was blue smoke from the exhaust and performance was down.

When the car got back here a compression test showed very little compression on cylinder number six and some pretty nasty noises from the cam gear.  The engine was stripped and the cam had something like 4mm of metal missing from the lobes.  Basically it was worn down and the particles had been going around the engine.  Harry opted for a total rebuild and a replacement David Newman cam.  This cam is less stressed that the original and should give a smoother idle and better mid-range torque.

At the same time Harry had a new cylinder head ported by Peter Burgess.  Peter has been doing Triumph/MGB/Crossflow heads for almost longer than I can remember and his work is as good as it gets.  So with a fully rebuilt brand-spanking-new engine Harry was back on the road – but with lots of pinking noises and misfires.  After some initial investigation Harry came back to Emerald for a running-in map.

The pinking was caused by a higher compression ratio and better cylinder filling from the Newman cam.  The misfire was another story.  The problem was that the rpm signal was dropping out.  One look at the trigger wheel showed up a problem.  The toothed wheel was slightly smaller than the pulley that it was bolted to.  You might be able to see in the pic that the sensor is off-set.  If you lined it up correctly the sensor was seeing the balance holes in the pulley and refusing to lock on.  It was such a fine balance to get it to see the teeth (and not the pulley wheel) that we could not leave it like that.  Half the car came apart and I turned down the Pulley to leave the teeth proud.  Then the bracket was re-machined/re-angled to line up correctly.

The engine was fired up and...it was still misfiring and playing up.  All that work and no real improvement!  To cut a long story short I tried everything to stop the misfire without finding it.  In desperation I decided to try a new coil.  The coil was new anyway and they never give trouble but I had to try something.  The mystery misfire disappeared!  Harry has since reported back that the engine “runs like a dream”.   Phew, some days are harder than others.

Cosworth V6 Turbo

We see a lot of V6 Cosworth engines here in various cars and some have twin turbos and some have a big single one.  Apart from packaging I can’t honestly say which set-up works best.  This one had a boost problem though.  The waste gate spring was supposed to give 10 psi but this rarely works out to be the case.  In this instance we were getting 20 psi of boost where we only wanted a maximum of 12 psi.  The compression ratio was stock so we needed to keep the boost down.

Taking the gate apart, one coil was cut from the spring which resulted in a boost reduction but still not enough.  Another coil off gave us 12 psi but then the waste gate stuck open.  The spring, we believe, was canting over.  It wasn’t a question of being too tight to buy a new spring; we just needed to get the mapping done.   310 bhp and 380 ft lbs of torque was the end result.

RX7 V8

Yet another RX 7 that has been “destroyed” by fitting a V8 engine.  When I say destroyed I am quoting the rotary engine fans here.  This one is used in sprints and hill climbs and the 480 bhp LS1 is said to give more than enough power for the weight of the car.  It was mapped previously by someone else but it melted a piston.  I never get involved in post mortem examinations or recriminations about other people’s mapping work.  I just got on and sorted it out.  Even more fired up about our twin turbo V8 RX7 now!

Honda Mini

This is a very popular conversion but not one I have seen here before.  The car was not really ready for mapping so it was left with us.  I fitted a crank trigger wheel and made up a bracket for the sensor.  The biggest problem was the lack of any seat.  Young Jono here brought in a Mini seat from home and we bodged it up so that the car could be driven on the rollers.  My first attempt, sitting on an upturned plastic bucket (bucket seat – geddit?) resulted in a near miss when the car shot forward and the steering wheel came off in my hands!  Luckily I am a crap driver and I stalled it.

Just over 170 bhp in a Mini should be exciting enough.  My first car was a Mini with a 34 bhp 850cc engine.  I “tuned” the engine by removing the air filter.  Well it sounded faster to my 17-year-old ears.

E Type

Don’t you just love ‘em?  I do but this one had an idle problem.  Easy fix: throttle body balance.  This is really important with a throttle angle system because all the injectors get the same squirt regardless of how much air they are flowing.  You really do need to balance the flow before you try to get the mixture right.  That’s it, lecture over, go and enjoy the rest of the mag.

Datsun 240 Z

Steve Kiddell is no stranger here at the rolling road; his Datsun 240 Z is a stunning piece of kit, over-bored engine, 45mm throttle bodies, head and cam work – it’s got the lot. It also has a new inlet manifold from John Mangoletsi – a name that will be familiar to more mature readers.  John has come out of retirement into semi-retirement and is producing new/old manifolds for cars like the E Type Jaguar and the Datsuns.  You can check out his web site for the latest offerings:  mangoletsimanifolds.com

Idle problems

It is not exactly unusual to get engine problems here at Emerald and sometimes you can follow the trail like a detective novel. This MGTF had a slow idle problem which I could not fix by opening the idle air control valve (IACV). A quick look at the throttle body told the story. The head of the adjusting screw had been sheared off flush with the body. This is a screwdriver slot job and normally has an anti-tamper cover over it.
The screw had been tightened right up and when the engine still would not idle; the last gasp turn of the driver had sheared it off.  The “mechanic” had then pulled off a breather pipe to allow enough air bleed for the engine to idle, but now too quickly. His/her answer was then to bend the throttle stop back until it no longer made contact with the screw. The engine now idled – sort of.
I had to remove the body from the car, drill out and re-tap the thread and fit a new idle screw, then bend back the tab to make proper contact.  I set the tick-over to 950 rpm with the IACV valve at 50 per cent of its opening. Now I had enough adjustment on the valve to get the cold and hot idle right just by using the valve.  Bloody amateurs!

GBS Zetec

I see a fair few Zetec engines in Great British Sportscars' kit cars. These engines are often used, lifted from the breaker’s yard without being stripped or checked. This example had a problem with starting which took a few minutes to sort out and in doing so we routinely checked for full throttle. It was making less than half throttle with the pedal to the floor! The owner/builder had adjusted his stops to get the pedals level but hadn’t checked the opening range. We had to bodge the pedal travel to get full throttle and I was driving with my right knee almost under my chin.
Initially it all looked gloom and doom; the exhaust was smoking really badly. I set about doing some light throttle mapping so that the car could at least be moved about under its own power. Magically, and very unusually, the smoke cleared and the engine performed faultlessly. We are seldom that lucky.

5000 RPM Fast idle

The Clio Williams had a highly modified engine that I had previously started mapping which then ran out of injector. Now it was back with larger injectors and a note from the engine builder saying that it was idling at 5000 rpm.  I have no idea why people think this is an ECU problem. Engines run on air and you cannot get air down a wire. If the idle is too fast then it has to be an air leak.
Sure enough, a quick look (and I do mean quick) revealed the problem. The new injectors had a much smaller seal than the originals and were literally floating about inside the head. I pulled them out, replaced the injector seals with the original injector seals and then mapped the engine. There is no excuse for this; any professional should have spotted that when installing the injectors and swapped the seals at the time. If it happens here I fix all these problems free of charge but if you were on a truly commercial rolling road you would be paying someone £100 an hour to do basic spanner work.

Thruxton GT 200

Actually this kit car looks more like an Austin Healey on steroids. This pre-production car was running a K1800 Turbo engine in box stock form and should make somewhere near 200 bhp – hence the name; GT 200. It mapped up on the money at 200 bhp and I was invited to take it for a test drive. I never drive customer’s cars on the road. It only takes someone to drive into the back of me at the traffic lights and I have all the insurance aggro to go through. In any case, I learn nothing that I haven’t already discovered on the rollers - but in this case I made an exception.
The car is very quiet in town but still attracted a lot of attention. A gaggle of schoolboys were pointing and I heard one of them say:”look it’s a seventies Thruxton GT200”. I was really impressed, not that he got the look of the car right so much as he could actually read. I thought most kids these days could only spell text-message style: Innit?
Once I got on the open road it was a pleasure to drive. I am not a big turbo fan but the response of the stock engine combined with not a lot of weight made for instant response – I loved it.

Booker Prize

I have recently finished reading one of the best books on engines that I have ever come across. It will never win a Booker prize or make the best seller list because those awards are based on volume of sales. But for me it was a page turner that I could not put down.

Roger Bywater has worked in the automotive engineering business for a lifetime, specialising in engine design and development with a long spell at Jaguar working on the V12 engine. His recently published book draws mainly on personal experience, not information gleaned from the internet!

There are 11 chapters in total covering just about every aspect of engine design, from camshaft and valve operation to pressure charging, inlet systems and exhaust design, all written with a view to explaining pretty much in layman’s terms how it all works. I really learned from this book but then I have known Roger for over 20 years and I always learn something when I talk to him. Let me give you an example.

I have always wanted to know why so many motorcycles run megaphone exhausts when you never see them on cars. Roger explains that the best way to get a reverse pulse in a pipe is by having an extreme section change; like an open-ended pipe.  That’s exactly what the early racers used. Then a rule change specified a minimum exhaust length. The megaphone started to appear just after that rule change as a way of getting a shorter pipe length while meeting the overall length rule. With a tapered megaphone shape, inlet or exhaust, the engine sees it as an uncertain length and the pressure wave usually reflects before it reaches atmosphere, part way up the pipe.

Roger goes on to explain how 4-1, 4-2-1 and six and eight cylinder exhausts work by interaction.  If you are an internet expert and already “know it all” then this book is not for you. If you want to learn how it all really works then I suggest you invest £60 in this soft-back book from AJ6 Engineering. Contact Roger on 01625 573556.

Cheap "rubbish" on eBay.

I hope it doesn’t sound like I am “talking down” to your good selves but I have had a couple of fuel pump failures lately which could have been avoided by doing the obvious.  I am talking about fitting a filter in between the fuel supply and the pump.  The pump MUST be protected by a filter no matter how new or clean you think your tank is.

Next the eBay demons have struck again.  Cheap (for cheap read “rubbish”) fuel pressure regulators, nicely anodised and with a fuel pressure gauge attached, can be had on eBay for very little money.  I have seen several now and they all fail to hold a consistent pressure.  If you have an engine that you don’t mind falling apart under load then by all means use them - you could save up to £30 and you can put that money towards your engine rebuild.

XJS

I mentioned Chris Palmer’s XJS recently and how I had gotten a bit involved in some head porting work.  I made the flow bench adapter and did some flow testing and then Chris supplied a head for me to cut up.  I could not believe how much metal this head has around the ports.

Once we had established the basic shape, the head went off to CTM (02085 921180).  Charlie at CTM did the porting work and skimmed the head to get the compression ratio up.  Once it was back on the car I had to re-map to suit and then compare the old and new power curves.

Whilst all the theory said it had to be better, that’s no guarantee that it would be and I was just a tad nervous when I logged the first power runs.  Peak was not really any better but the mid-range torque was way up on the previous engine.  Last year Chris had been beaten a couple of times where he normally tends to dominate his class.  Three wins out of three races made for a pretty good start to the new season!

XJS Two

I had a second XJS in this month from the same race series.  All seemed to be going swimmingly until the first power run when it dropped one cylinder.  The car went back to base and the head was pulled off in something of a hurry; the first race was only days away.  Nothing drastic was found, just some mysterious carbon under two inlet valves. A quick clean up had the valves re-seated and it was back within days on the rolling road.

I had agreed to work late one evening to get the car out for the first race.  In the end it wasn’t necessary because someone cancelled and we had a bit of time free.  Peak power was actually pretty good for an engine on the standard intake system and the owner/driver (Roger Webster) made the first week-end’s racing in the nick of time.  Not a waste of effort either as he came home second in both his races to Chris Palmer.

Lucky Butts

I have known Steve (Lucky) Butts for about ten years now and his rolling road visits are always good value - in terms of entertainment.  We call him Lucky because he is the unluckiest person I know; the first car we mapped for him caught fire and burned out!

For this trip Steve wanted his new engine setting up.  This is a 1400cc K Series that he wanted to run in the supercharged class in hill climbs.  This engine stated out as a “MG/Rover works special” and Steve had rebuilt it for his Lotus Elise S1.  It features all the right bits, steel crank, rods, forged pistons and a supercharger as well as a turbo: quite a mad piece of kit.

The first start up was interesting in that it would not start at all.  There were a few encouraging coughs but no real sign of life.  We pulled the plugs to check if they were wet with petrol, which they were.  A compression check came next.  Compression was good but we seemed to have something flying up the plug hole of one cylinder – which looked like paper!  To cut a long story short the inlet manifold was pulled off to reveal a lot of blue paper stuffed down the inlet ports!  I took a couple of pictures and promised Steve I would never embarrass him by telling anyone – so keep this just between us okay?  Hooray it ran, but Steve was soon on his way with a to-do list.

A week later he was back with solid intake hoses and a supercharger-throttled intake system.  With race cams and the biggest volume plenum intake in the world the idle was not bad – it was non-existent.  The best I could manage was about 2000rpm and lumpy as a lumpy thing.  Steve, being a cheerful chap by nature, could not care less, it was running and he wanted boost – lots of boost.

The supercharger appeared to be delivering about 12 psi at very low rpm and the turbo then topped this up.  We did a couple of maps, a base line boost and then one with more boost across the rev range.  I had my doubts that it would be driveable on anything other than the “girlie” low boost map - it was pretty ferocious.

Lucky managed to get to the first event and had fun trying to get the car off the line with his super-fast idle.  Even so, he got his first class win and the time was 0.1 seconds under last year’s class record. The target now is to get under the current course class record and that means finding more driveability and probably more boost.  With a project like this you can never expect to get it right first try - it’s called “development” and it takes both time and money.

Super/Turbo Two

Like buses that come in pairs I had a second turbo/supercharged car in this month: this time a Renault Five.  When Lucky’s supercharger made too much boost on idle the first time around this one made too little.  Two psi wasn’t exactly what we wanted and all the boost was coming from the turbo.  We messed about all day but you can’t fight the laws of physics - it just wasn’t working without a smaller supercharger pulley or a bigger supercharger.  Steve’s engine proves that it can work (sort of) so a bit of head scratching is needed on the Renault.  No doubt it will feature here again at a later date.

Boost block vacuum distribution

My mate in Florida, who trades as “Emerald Performance” has come up with a vacuum distribution block which is apparently all the rage in the U.S.A.  The idea is that you take one big vacuum from the engine and then use the block to connect everything else to it that needs to see a vacuum signal.  I don’t have a need for them but if you do then contact the above.

R32

Richard Johnson is a regular here with his turbo R32 and this month he was back with a four-wheel-drive conversion and a revised exhaust manifold.  I can’t give you any detail on the manifold but the result was simply amazing.  The boost comes on much, much sooner, faster and holds on at high rpm.  This is one of the aspects that many turbo enthusiasts seem to ignore and it’s something we want to investigate if we ever get the Superflow engine dyno up and running.

I heard a theory once about wires:

If you put two wires on the floor, (side-by-side) and leave them overnight – when you come back in the morning they are twisted together.  Wires have a life of their own.  It must be true because I see so many cars here with wiring problems.  For example: a wire has to run from A to B.  It starts out at A, but somehow ends up at C.  The car’s owner swears it was all wired correctly so obviously the wires are moving about in the night; there’s no other possible explanation.

Having established that wires love to move about, what is it that they hate?  It seems they hate being connected to anything.  A classic example was the car with a bad misfire that came in about half way up the rpm range.  This coincided with the speed and load point where the outer injectors were supposed to come on.  Since you can see the injectors on this particular car it wasn’t hard to establish that the back pair were not spraying any fuel, whereas the front pair were.  Aha…obviously an injector driver failure because everyone knows that the injectors share a common feed.  Except that is, in this case; where two separate feeds had been used.  A quick check showed that one of the feeds was broken at the connector…obviously the wire had disconnected itself.

Mapping continued until we got above 5000 rpm when the engine began to misfire again.  A look at the logging trace showed that the engine rpm signal was disappearing.  A quick tug on the crankshaft sensor wire resulted in no rpm signal at any revs so off it came to reveal yet another break in the wiring.  These things don’t take long to find but they are a pain.  My job is supposed to be mapping of the engine, not re-wiring and fault finding.

Peugeot 106

This one had me worried because the owner had taken another ECU off the car to fit our system.  The worrying thing is that all aftermarket ECUs work, you might not like how they work but they should work.  It seemed to me that there would be a problem with the car rather than the previous ECU and that problem would end up with me - it proved to be the case.

The throttle pot on the bike throttle bodies gave no reading that you could make any sense of.  For a start it was wired wrong but sorting that out left me with a problem.  I could not get the tongue drive on the butterfly shaft to operate the pot correctly.  It appeared to be a left hand pot on a right hand spindle.  I had to fit the pot so that it was fully against the return spring when closed.  That was the only way to get a reading and then the single retaining bolt did not line up!  I have to confess I bodged it with a cable tie because my job is to map cars and I was up to me neck in “problem” cars.

It may not have been an elegant solution to the problem but as a temporary repair it worked and the car was mapped up okay.  I have talked in the past here how I dislike bike throttle bodies so I will not go over it again, they work, but not very nicely.

Audi Elise

Problem car number three in a single day was this Audi powered Elise: misfires and rough running.  It had been mapped previously but not by me.  The first thing I do with any new installation is go though the map looking at all the settings.  It all looked okay apart from the fuel numbers seemed a bit strange.  Then I discovered that the engine had 800+ cc/min injectors which explained a lot.

Looking at the map sensor settings they were set up for a Weber/Marelli 3 bar map sensor but on the live mapping screen it showed 92 Kpa with the engine not running.  According to my baro reading on the rolling road computer we had near as damn-it 100 Kpa pressure in the cell.  Closer observation of the reading showed that it was actually floating about, anywhere from 90 Kpa to 96 Kpa.  Basically it was on the way to failing, if not totally failed already.  A quick phone call revealed all: the sensor was not an actual Weber/Marelli part but an Ebay Chinese copy!

I can’t see the sense in this; you have a massively expensive engine yet you fit a safety critical part from an unknown source in order to save £40.  Is it really worth the risk of losing an engine that cost thousands of pounds in order to save £40?  The Chinese rip-off merchants strike again it seems.  While I am on the subject can I also warn readers about the cheap pressure regulators from China, the shiny ones with the little pressure gauge on the side.  Yes, we have seen them fail on the rollers too.

LS V8 Mazda

I have to confess to liking these “Batmobile” RX7s.  Not with the rotary engine but with the big V8 LS motor.  I have done quite a few now and this one was pretty routine at just 6.0 litres.  There’s only one word to describe the sort of power these engines make: “lazy”.  It’s all so easy; applying a little throttle you tap the keys and look up to see 200 bhp at the wheels.

For the engine size the bhp/litre might not be that impressive but at the end of the day you still have massive lazy torque under your right foot.  I can’t wait for our own project car to hit the road.  As I write Craig Taylor in Birmingham is putting the exhaust system on the car and it’s real close to firing up for the first time.  I am not holding my breath or making any promises but we just might make Mallory Park for the PPC day...

MGB K 1800

Last issue (or the one before) I talked about young Ollie and his K Series 1800 MGB.  The caption on the picture told the story of how Ollie came real close to winning his championship.  However, if you read the copy it tells you that he did actually win it, a close run thing but he was the championship winner.

The car was back this month for a re-map on a new engine, in fact I do all three of the Neaves family cars, all MGBs and all 1800K Series.  If you look at the cost of fitting a 190 bhp K engine compared to running a full race B Series engine it makes a lot of sense to go with the K motor.  Surprisingly the original MGB engines are actually a bit faster over a lap but the cost is prohibitive compared to a K Series.  Luckily the organisers recognise this and allow the MGBK into the series.

In a previous life I used to prepare a Mk2 Escort for circuit racing.  I also used to build the engines and do the flow bench work on the heads, which is why I still have a Superflow 110 flow bench.  I reckon that from a 2.1 litre Pinto you can see 210 to 215 bhp but that’s your lot.  The example that came in for mapping was a track day car just converted with Jenvey throttle bodies.  Back in the day my fast road engines used to make 165 bhp – measured on an engine dyno so that was real world figures so those were the sort of numbers I expected to see.  After fully mapping the engine it proved to be a little down on power so I suggested we look at the cam timing.  With any single cam engine you are fairly limited as to what you can do with it.  I set my cam timing by measuring the lift on overlap at TDC.  This is now an accepted method and one you see expounded by various experts on the net but I had a hard time convincing people that it was the way to go.

With the Pinto engine I use a rule of two thirds.  That is to say that I advance the cam until the exhaust lift at TDC is two thirds that of the inlet valve.  For example if the inlet valve is 90 then the exhaust would be 60.  A calculator is handy because the numbers never come out in handy exact figures.  This then is the most advance you will ever see and I retard from there until I get the best average power.   We ended up with something like 150 bhp which isn’t bad for a road engine. Probably with some big valves and more head work it would get to 170bhp but when you think that you can buy a Zetec 2.0 that makes 170 bhp as stock for less than the cost of tuning the Pinto that’s really the way to go - unless you are into Historic events.

Jag XJS

I have been doing Chris Palmer’s XJS racer for a few years now and Chris has had a fair bit of success with it.  Trouble is the opposition are now really not playing the game.  This year has seen a bit of a power struggle taking place and Chris is finding it very hard to get on the podium, let along win outright.  For the 2011 season Chris has asked me to help him find some more power and suggested that new cams might be the answer.

But before you can order up a new camshaft you have to have some idea of what’s needed.  I asked Chris to take the head off the car and let me flow bench test it.  It helps to know how much lift you can usefully have before the port bottles up.  Over-lifting a cam is a crime in my book as it adds a lot of mechanical strain for no performance gains at all.  In order to flow any head you have to have a bore adapter.  I scrounged around my next door engineering shop and came up with a large tube in almost the right diameter.  It needs to replicate the bore of the engine.  On the lathe I turned out the tube to 92mm and then set about making up some wooden platforms to support the head and locate the bore.  That sounds easy but it took me a full day to achieve.  Next you have to make up some sort of bracketry to hold a dial gauge and a screw to hold the valve open.  You have to take flow readings in stages, I use every 0.050 inches because that’s how I started when I first bought the bench in 1987.

Having established where peak flow was we can now look at the camshaft.  To be honest this is not the most powerful engine in the world.  300 bhp from 4.0 litres equates to 75 bhp/litre - which is pretty poor for a four-valve head.  I spoke to Roger Bywater at AJ6 Engineering.  Roger was on the design team for this engine when he worked at Jaguar.  He said that the engine was never meant to rev and that the 3.6 actually gives better specific power in terms of bhp/litre.  It seems we are destined to struggle with this one but I have a few ideas up my sleeve and I will let you know how it goes in due course.

300ZX

Regular readers will know that I am not a big fan of turbo engines, even though I concede that they make big power.  The big power in itself can cause problems and I don’t just mean the heat and thermal loadings.  Fuel requirement is vast and you need a fuel pump and fuel lines that can keep up with engine demand.

This particular Nissan made very good power but there was a problem we could not pin-point.  Inside the car we had a terrible smell of fuel as well as a pressure drop-off.  We had a good hunt around but couldn’t find the source. After a while you start to convince yourself that there isn’t a problem, that it’s just one of those things; poor air circulation in the test cell or a badly sited breather.  Off the car went and the owner later reported that he could not find any leak on the car but the smell of fuel is still there.  The clue is probably in the fuel consumption: 5 mpg around town and 11 mpg on the motorway!  I have been mapping a while now and nothing I have done has ever been left that rich – it has to be a leak.  The problem appears to be finding it.

Engine Dyno.

About four years ago we started to install a second-hand Superflow 901 engine dyno here in the workshop.  A cell got built which was big enough to take a complete car, sound insulation went in and an extraction system was plumbed in.  It was all looking tickety-boo until we tried to run the dyno.  Basically it read 888 and not much else.  The man from Superflow said we were suffering from “the crazy eights” and that the computer board needed to go back to the U.S.A.

It came back a month later and hey-presto!  It worked for about 30 seconds and then…888 again. There were other problems like the load control unit not working and the load cell had been superseded, it just went on and on.  Basically we gave up.

Now we have recently taken delivery of the latest Superflow 902, all digital kit and touch screens but we still can’t run it because the extraction is basically flawed.  We need to extract air from the room, not blow it out from one corner as per our current arrangement.  We are now organising the building around the new extraction system and have two fans coming that will pass 460 cubic metres per minute, or 11 Olympic swimming pools of volume per hour.  That gives us 10 changes of air per minute; we don’t want the engine breathing in its own fumes.  It is taking forever because we have to fit all this in between working for a living but it’s nearly, nearly there.  If we ever get it all working it’s going to generate some interesting editorials here in PPC – a lifetime dream come true, I just hope I live long enough to get some use out of it!

I’ve just got back from Autosport International and four days of helping to man the PPC stand.  I have to say how good it was to meet so many readers and get their feed-back on the magazine.  I also particularly enjoyed seeing our esteemed Editor backed into a corner trying to explain exactly how he managed to crash his Quattro pretty much while going in a straight line!

Thanks for the comments both good and bad, it all helps the editorial team direct their efforts towards features that you really want to read about.  For my small contribution I was surprised how much interest there still was in the old CCC Project Shed.  My Fiesta is actually running now and Kev has twisted my arm to bring it out at the PPC Party in the Park at Mallory.  Since that’s still some way off I have agreed to get it track worthy again but no doubt it will be a last minute panic looking for tyres and spanner checking the suspension etc, a day or so before the big day.  Maybe I’ll see you there?

Jaguar D Type

Back at the ranch it was a bit quiet just before Christmas but I still had a few cars booked in for the rolling road.  A superb D Type Jaguar booked in running three Jenvey throttle bodies that had been fitted inverted to make them look a bit more like the original Jaguar D Type injection system.  This made it a bit of a pain to get at the throttle stops but it did make a big difference to the under bonnet look.

I had previously run this car up on twin SU carbs and while the top end mixture had been about right it had been running far too rich in the mid-range.  These beautiful classic straight six engines never did actually make the power claimed for them but they were still pretty potent for their day.  The Jenvey bodies added another 25 bhp to the peak power and this example was not far off what the works cars were claimed to be running in 1955.  The nearest I have ever come to owning a D Type was a Scalextric model so it was really nice to sit in a proper car and pretend that I was humming down the Mulsanne straight passing works Mercs; instead of sitting on a rolling road tapping away at a keyboard.

Mankee Caterham

No doubt you will read elsewhere in PPC about Mankee coming here with his Caterham for a power run.  He was concerned about the mapping with a lot of track days on the horizon.  Good job he did too, read about it in his section of the mag.

Young Ollie

I have been setting up Blaine Neaves’ K Series MGB for a while now and last season I did all three cars when his two sons took up racing. One of them, Ollie Neaves, managed to get real close to winning his race series.  It was all down to the last race and knowing that he did not have the money to do all the rounds next year he was desperate to get the points.   Having done just that he then lent his championship winning car to a competitor so he could experience for himself what a great conversion the K Series is in the MGB.  To cut a long story short Ollie is now building a new engine after the blow up!

Capri

I see a fair few Capri's in one form or another but just lately the Cosworth 24 valve V6 seems to be the favourite.  The example shown here though was a bit different.  This one sports a Rover V8 with a supercharger.  The idea was not to go for massive power but more a spread of torque that would be good on the road as well as the track.  The boost was not quite there at 4 psi but it made 250 bhp and a wall of torque.  One interesting thing was the tacho.  The owner reported that he had been to 7,000rpm on the tacho and it had not blown the engine.  I was getting peak bhp at about 5,800rpm on my computer screen.  It turned out that the tacho on the dash was over-reading by about 1000rpm!  I think I could well be seeing this car again with either a different blower or different blower drive ratio.

Electric Elise

Probably the most unusual car I have ever had on the rollers was an all Electric Elise, done as an independent project, not an official Lotus offering.  This was a professional job pretty much built from scratch, rather than a DIY conversion.  To say the least the driving experience was “weird”.  For a start you have nothing happening on tick-over because there is no engine to tick-over.  You select drive and then put your foot down to pull away.  I found it really hard to get my head around what was going on.  The idea of maximum torque at no rpm was a concept that I could not come to terms with; putting your foot down at any rpm gave instant wheel-spin.  One of my tasks was to run the engine under power to see how long it took to drain the batteries under load.  I set the power at a given road speed and just watched the bhp reading dropping down.  At one point the power dropped to zero and the road speed started to fall away.  Then the bhp reading went up again as the electronics sorted out which battery had what left and re-distributed the load.

I have no doubt in my mind that an all-electric car would have superior performance over the infernal combustion engine and sooner or later the technology for batteries and charging will make it a lot more practical than it is today.  At the moment range is the problem and the time taken for re-charging the batteries.  Regarding the “Green Credentials” of the electric car I have my doubts.  If the power comes for a power station with a dirty exhaust what’s the difference?

I know it’s not a popular view but I don’t personally believe a word of all this Global warming business.  My feeling is that it’s just a convenient story so that the Governments around the world can tax us some more and blame global warming rather than owning up that they are peeing our money up the wall.  If we now have the worst weather and floods for 50 years then surely that means that it was just as bad (or worse) fifty years ago?  Stick up the VAT, put more tax on petrol and its bonuses all round eh chaps?  After all, how can you complain when the politicians are saving the planet: remember; it’s for our own good.

No matter what they deal in, most companies, large and small, have some sort of R & D department. The R stands for “Research” and the D stands for “Development”. Most readers understand this and when they embark on a conversion they start by doing their research.

This may entail nothing more than phoning around or doing a web search for information on the conversion they have in mind. Having done their research said reader then buys the bits and bolts them together. Next comes the bit that most people do not seem to believe applies to them: development. No matter how much research you do unless you are going down a well proven path you cannot expect your initial efforts to be spot-on. That’s what development is all about, some people call it: “suck it and see”.

If you got the research bit wrong then the development path can be long and painful! Take camshafts as an example. Some people fit far too much cam based on the theory that if big is good, then bigger must be better. There’s more to it than looking at a cam catalogue and picking something based on a theoretical rev range. You need to look at the overall package. A cam with high rev ability isn’t much use if you can’t rev the engine because it has a wobbly crankshaft and cast pistons.

The temptation is that you find a proven package and then think that you can improve on it without doing any testing. Engine builders who are any good will have done all the testing they can (or can afford) and what they sell you is a proven package. I am not saying that you shouldn’t experiment but be realistic; your first effort may be a disaster so you have to work on it, that’s what development is all about. Point to note: development is expensive, are you sure you can afford to experiment?  Another point to bear in mind is a realistic target. I had an American asking me about a Zetec 170 that he wanted to bolt throttle bodies to and get 250 bhp. That is never going to happen.

V6 twin turbo

Some cars are a real headache when they turn up here for mapping – and some are a real nightmare! The twin turbo Ford V6 engine was of the later variety. Basically the owner had paid a man £400 to fit his ECU and get it running on the base map. The car came in not running but it did splutter a bit and the installer said that it just needed mapping. No problem, that’s what I do.

I won’t go into all the details because it gets boring but 12 hours later we had the car running. If we had known that the whole installation was such a cock-up we would have ripped it out and started anew right from the beginning. The trouble is you keep thinking: “if I can just get this bit working the rest is going to be okay”… but it wasn’t. One real howler was the way the throttle pot wires had been extended. Nice twisted wires and neat solder joints, then the wires were not insulated to keep them apart but just taped into the loom. The result was a dead short.  All the terminals going into the ECU plug were attached via bullet connectors. This tells you straight away that the installer had no confidence that he/she were putting the right wires in the right holes. To make matters worse the bullets were crimped on the insulation and the only contact was where the bare wire touched the head of the bullet.

When we did finally get the engine running there was the question of two tiny turbos on a stock compression ratio engine. The owner had been told that a standard engine was no problem to turbo-charge (10 to 1 CR) and that small turbos would eliminate any turbo lag.  The theory may sound plausible but what happens when the engine rpm rises and so does the turbo rpm? The answer is that the turbos go into over-speed and fly apart! Having a 10 to 1 compression ratio is just about okay if you have very low boost levels. Do not believe what the Americans tell you about total reliability with high CR and big turbos. They are only running for a matter of 8 to 10 seconds in a straight line, they would never make two laps of any circuit here in the U.K. That particular V6 will be back when all the install problems are sorted.

Cam timing tip

When I have to swing the cam timing of an engine on the rolling road I always try to take Sod’s Law into account. This irrefutable law says that once you have found the optimum position for the cams you will never get it back again once you move away from it. And move away from it you must otherwise you don’t’ know that it’s already optimum.  What I do is take a digital picture of the cam wheel. Next I can use the display screen on the camera to “zoom in” and then even a cross-eyed ageing motoring journo can clearly see where the original marks were.  Once you have the cam timing right, just delete the pictures. Computers – do you think they will ever catch on?

Boost pipes

It does not seem to matter how many times I mention this: people are still turning up here with stainless steel pipes and silicon rubber hoses on their boost pipes with no lip to help hold the pipe in place. Stainless is shiny and hence has a very smooth surface. Silicon is slippery – guess what happens when the boost tries to force them apart?  Correct; the pipe blows off. This is not just a question of being inconvenient in that you have to get out and push it back in. The sudden release of pressure on the compressor wheel can send the turbo rpm into orbit and damage the turbo.

The fix is really simple: put a few dimples into the edge of the pipe. It does not have to be a superbly formed rolled edge (although that’s nice), as you can do it very easily as on the pipe I fixed in the picture. Get the edge hot and bash a lip into it with an old screwdriver. I just put three lips in at roughly 120 degree intervals. Even with a thin Jubilee type clip it still held on under boost. – at least long enough to get the mapping done.

Elise throttle

Jenvey direct to head throttle bodies are my favourite conversion for the K Series engine. The design of the butterfly position allows you to run as much cam as you like and still get a superb idle and light throttle drive. I can say that with some confidence because I have seen all the different body types on this engine.

The one pain is the throttle linkage on the Elise. If you retain the original cable and make up a bracket to hold the outer adjuster at the body end, you can only just get full travel with everything adjusted correctly: except on the throttle linkage shown in the pictures. On this particular Elise the pedal box linkage was worn.  I turned up new bushes in nylon, tweaked the arms and made all the adjustments I could – but still failed to get full throttle. I think on this slightly ageing car I need to pull off the bodies and re-drill the link arm to gain a bit more travel. When the car came in it had about 50 per cent travel and went out with about 90 per cent.   Full throttle is a fairly basic requirement so check before you take the car for mapping. If the rolling road operator doesn’t pick up on it you have wasted the day’s mapping – and your money!