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?
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.
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!