Walker’s World April 04

We’ve had a few tear-your-hair-out cars this month, always new installations and nearly always wiring problems. The Pug 205 turbo was especially painful because it was going to be a big power engine with water/methanol injection. Straight off the trailer it fired up – but only on two cylinders. Tracing the wiring we soon found that the second injector bank had been wired into the wrong pin on the plug. With the pin moved we had a three cylinder engine!

The turbo blows through some very pretty CNC machined throttle bodies. I can’t honestly see that this is worth the trouble since a turbo always runs small overlap cams and the plenum works fine. Throttle bodies do improve idle quality with big cams but if you are not running a big cam…

Pretty as these bodies are they can be a pain in the backside to set up. The master body drives the other butterflies so you have to start with number three cylinder and then match the rest to that one. The lever arms clamp in any position (no locating D-flat or spline) so you can get them very wrong if you are not careful how you put them together.

To cut a long story short we had endless problems with balance which was made more difficult by not being able to easily remove the intake to get a meter down the throats. Eventually the car was running on four cylinders - after we found a dodgy connection on number four injector plug pin (it had pushed back making intermittent contact).

Removing one injector for flow testing was fun. The fuel rail has more steps than a spiral staircase and I lost a little anodised spacer and had to turn up a replacement. The injectors had enough flow for about 225 bhp flat out at 4 bar pressure. I fitted a pressure gauge and set the adjustable regulator to 4 bar. After a whole day on the rollers we were finally ready to start mapping.

My first worry was the emulsified oil and water coming out of the engine breather. I didn’t think the head gasket had failed but it was still a worry. The boost was on minimum and after about ten minutes I felt something was wrong with the mapping. On checking the pressure compensation table I found it full of zeros!

The owner had loaded an aspirated K-Series map as a base setting which obviously does not have boost pressure compensation. I filled in the numbers and started again. I was almost there when I had the fright of my life. The engine appeared to bust apart in a massive cloud of smoke.

It turned out to be steam and hot water because the top hose had fallen off! The housing had some damage and the retaining clip hadn’t been fitted fully home. More delay, more anti-freeze and more years off my life. I finally settled on a power run with the turbo boost logged at just 5psi. The flywheel power was a creditable 170bhp. Then I spotted the firework display under the bonnet - part of the loom had been chewed through by the alternator.

With the breather problem and the dodgy top hose I called it a day at 170bhp. Once these issues have been addressed we will probably have another session with water/methanol injection switched on and the boost wound up.

Trials

I did my first ever Trials car this week. This car makes a Caterham look big; tiny chassis with beam front axle and a Peugeot FWD engine and gearbox.

To get super low gearing you take a FWD engine and box, turn it sideways and drive from one shaft to the rear axle diff.

That way you get two final drive ratios before the power reaches the wheels.

The rolling road needs a figure for rpm at 60 mph: this Trials car would have to rev to 10,200rpm to make it. I mapped in top gear and saw 40mph at peak rpm.

It was a completely mad experience. When we had finished the owner opted to drive onto the back of the lorry (an angle of about 30 degrees) I had some misgivings until he put it in first and the car drove up on tick-over at 950rpm.

If you could find the grip I am sure it would climb the vertical wall up the side of a house - no problem.

Red Rose

We are looking at fitting the Emerald unit onto a TVR Red Rose special. This car features the 4.5 litre AJP engine with ported heads and raised compression ratio. The cylinder bank angle is 75 degrees which makes it a tricky one since the cylinder firing is uneven.

I know very little about these cars and even less about the engines. A friend of mine called it a “Red Nose” special and said it was a joke. I’ve just run it up on the rollers in stock form - nearly 400bhp is no joking matter.

We have seen an awful lot of poor Rover V8 engines over the years and the very best 5.0 litre ones are making in excess of 330bhp.

This 4.5 kills the Rover offering stone dead. What’s more it revs like the devil: peak power is currently at 7000rpm. More on this one next month when we really get into it.