Air Flow Meter

[Bosch, AN, Andrew, Dr]

> 
> I have serious doubts about this bigger flow meter stuff. Before you
> embark on fitting another flow meter, I think it would be a good idea to
> determine if the flow meter is offering any significant restriction. Don't
> just assume that it is. Do a pressure drop test accross it. It does not
> make sense that the manufacturer would fit one too small. The vane would
> bottom out before full flow was reached. The flow meter is the systems
> only load sense so the ecu could not determine fuel requirements beyond
> that point. Result? High speed lean out and a big warranty claim. I don't
> think they are that stupid!
> 
> As for the throttle body being too small and the inlet runners as well, I
> think you overlook a significant number of facts. Inlet tract size (length
> & diameter) is based on gas velocity requirements, cylinder volume and
> sound wave propergation. It was demonstrated 25 years ago that high power
> output did not equate to the biggest possible valves, inlet passages and
> throttle size. In my not so humble opinion, I think you are embarking on
> the degradation of your low speed performance and drivability. There is no
> point in having an inlet tract that will pass x+y cfm when the engine will
> barely consume x cfm at full noise. Get my point?


Hi again

Sorry, I wasn't very specific. The reason for all this "A/F meter too 
small" stuff is that this motor is fairly modified: with Weber 45 
sidedraughts it makes 170 KW (~230 HP). The stock fuel injection 
can't match that, so I've been looking at ways of getting more fuel 
(variable rate of gain fuel pressure regulator or extra injectors and 
controllers) and/ or more air. Ultimately, what I really would like 
to do is get an after-market FI system with individual throttle body 
injection

Andrew






Dr A. N. Bosch
Physiology Department/ Sports Science Institute
University of Cape Town Medical School
P. O. Box 115
Newlands 7700
South Africa