Hi i have a single T04E turbo set up...with stock intercooler and fuel pump and injectors...i was wondering what would be the a safe high boost limit...how much can i increase my boost till with the powerfc installed that my car does not lean out.....i have intakes and free flow exhast also.....your advise is greatly apprciated..





thanks..... https://www.nopistons.com/forums/pub...R#>/violin.gif

just depends on how high your luck is in russian roulette https://www.nopistons.com/forums/pub...IR#>/blink.png

10psi till you upgrade the fuel system and intercooler. Not to mention it will need tuned if it doesn't already.

.8-1.0k with a better fuel pump and some tuning. If you run on the map that comes with the power fc for twins, you will have a slight rich spot at 3500-4000, and a big lean spot from 4000 up. The car will run for a couple of months maybe, but then you will be buying a new motor. I have tuned 3 such setups in the last year, all had aftermarket fuel pumps. By using a stock fuel system and a larger pump, you are effectively getting higher fuel pressure, which makes the injectors flow more fuel than they are rated at.

If your using the stock fuel pressure regulator, why would you have higher fuel pressure?

because the stock FD doesn't run 1.0 kilos boost. The stock one is a 1:1 regulator, so running higher boost = running higher fuel pressure.

Because the aftermarket pump flows more. All the regulator is is a small hole in a blocked off place in the line. If you increase flow before the regulator and do not open up the hole you are increasing pressure before the regulator.

Is what I think should of been said was, with a bigger fuel pump you increase fuel volume, not pressure. The stock fuel pump runs out of fuel under higher boost. Just my .2 cents

chuck

Shouldn't the regulator just allow the extra fuel to flow down the return line to keep the desired pressure? i.e its not just a fixed size hole. Obviously at some point you would get to the point where the regulator could physically not pass enough fuel to maitain the desired pressure, but this would be more of an issue at idle when the injectors are not passing much fuel and if the two stage pump speed is not being used.



In regard to JSpecs post, I realise you will have higher fuel pressure at higher boost, my question was relating to the effect of changing the fuel pump only.

Have you ever tried to measure fuel pressure on a stock system with an upgraded fuel pump? I have and you will ALWAYS see more pressure at the rail with a pump that has a higher flow rating.