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Hello,
Well, it has been over a week since I installed water injection and a 5th fuel injector to my 8V turbo. The results are pretty good but there is one underlying problem still there that I have had since installation. That is, that on initial turbo boost (most noticeable in 4th and 5th) from 2100 to 2400 rpm, the boost rises from 0 to 14-18 psi, which results in a brief 'pre-detonation' metallic rattling noise from the engine bay, causing the boost to retard to about 10 psi. If I keep my foot on the throttle after 3000rpm the boost will rise again to 17+ psi before slowly tapering off to about 15 psi nearer 5000 rpm. This is exactly what I would expect.
What I have been attempting to do over the last week was rid myself of the <3000rpm pre-detonation. I tried a number of things. I set the fuel injector controller (ERL's MF2) to give maximum fuel enrichment at all rev bands from 2000 to 6000, I set the water injection kick in earlier at about 8 psi (was 10 psi before), had fuel injector kick in earlier (8 psi)and went to the extent of fitting a second fuel injector.
No improvement was noticed by doing any of these things in preventing the pre-detonation below 3000rpm, but to repeat again, after 3000rpm if you push the car to full boost it will do it no problem with no pre-ignition noises. The biggest surprise was the fact that two injectors working together made no difference.
For those who didn't read my posts on here last week I should let you know that I have been using 'cold-start' fuel injectors and not normal EFI ones as my 5th, and now 6th injectors.
No matter what I am going to get a 16 ohm electronic fuel injector and fit it instead of the cold start valves I have been using before, because I cannot help thinking that the biggest demand on the engine is probably to get the initial boost rise completed, and the cold start valves probably cannot flow enough fuel.
Does anyone have any other advice / comments?
TIA
Angus M Smith
posted by 213.40....
, Tue, 14 Aug 2001 10:52:36
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