Quote:
Originally Posted by axsaxoman
a std ecu is in closed loop control at most times except for certain conditions decided by the ecu designer ,
std vts ecu is in closed loop at everything but fullthrottle up to around 4k ,after that it is open loop from around 70% --these are not exact figures -but your worry about raising fuel pressure and mot is unfounded ,the std ecu is adpative and will correct quite happily when using a 4.5 bar reg ,but yes it will make it richer on WOT.
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Thanks John,
ok so (and there is a sale in it for you depending on what you say but I'd like your
honest opinion), based on what you're saying, a 4.5 bar fpr on my engine, standard internals, induction kit and lower restriction exhaust, will be fine - but what about 70%-T to WO-T how rich are we talking? too rich and kill the top end? or is there top end power gains to be had? Although it's not my priority (see below).
Quote:
Originally Posted by axsaxoman
I,m not sure what you are trying to achieve ,but if by effiency you mean economy ,then there is a lot more to it than making car run lean
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You're correct about my desire to improve the economy when I was referring to efficiency. but I wasn't referring to running the car leaner at part throttle or any other running condition. I'm referring to better atomisation of the fuel, through a higher fuel exit velocity at the injector that would occur with a higher fuel pressure.
So essentially I'm after a better burn from a
fixed amount of fuel - which would be the case if we're at part throttle, closed loop, but comparing a standard fpr (3 bar isn't it?) to a 4.5 fpr. The system with the 4.5 FP will have a shorter injector pulse duration - which means the fuel has to exit the injector with a higher velocity to ensure the correct mass flow (to maintain the ECU's required AFR).
If the gains are negligible, or there is something I've overlooked which means it'll scupper ecomony then don't worry. If the gains are minimal but there are gains to be had, then I'm interested.
Thanks!
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