Fuel pressure

[jimnielsen]

I need to increase the amount of fuel that the car is getting at high boost / revs. Currently I am getting up to AFR 13, at the top end - which is too lean. The problem is that I already have the fuel table at max at the top end... You cannot put values over 17.32 (milliseconds) into the Injector table in the P8 ECU - as that corresponds to FF in the 8 bit fuel table cells..So in other-words you can't run the injectors at higher than 80% duty cycle, as the software does not let you..

thus, I want to increase the fuel pressure with the standard (adjustable) fuel pressure regulator that the Q4 has... So that I can get more fuel flow in the allowable injector opening times (yes, I will have to adjust all the table.. but E85 is quite forgiving of running rich..)

My current static fuel pressure, measured with the ignition on, but the car un-started is 42psi.
I'd like to increase it to at least 45 psi. (yes I have enough fuel pump capacity..)

My question then is for those of you that have adjusted the fuel pressure (for a squadra or what ever..).. What static fuel pressure are you running - can I get it to at least 45 psi using the standard reg??

[wrinx]

Would larger injectors cure your problem?

wrinx

[jimnielsen]

well, yes, but they create a problem at the low end, as the minimum opening time for idling starts to become unstable. I am using 630cc injectors as opposed to the 384 cc original ones - so with a bit of extra fuel pressure, that should suffice. but, I do need a bit of something extra..

[SteveNZ]

Yes, I ran 51psi static for the same reason. There is a lot of adjustment in the standard reg.