Hi Guyz


I recently finished building a L83 with forged internals and .5 lower compression so 10.5 for my Sierra with a twin turbo kit from armagedon.


My truck was dynoed at 510whp pre engine build and while trying to boost it up now im facing some issues with fueling im running a completely stock fuel system with the exception of the cam with 30% increase on fuel.


When I exceed the 570whp mark I notice my fuel pressure dropping both on the High and low pressure side my low pressure actually goes as low as 20psi vs the 40s it maintains with lowers HP.


I have been told the stock fuel system would max out on a much higher number then this.


Whats the general opinion on the limits of the fuel system?


Are their any ready solutions, I really don't feel like reinventing the wheel?

 

You can try a ZL1 Pump or one from a Caprice PPV. Its the same part number. The Caprice PPV requires a higher flowing pump because it runs on E-85.

 

If low side is dropping that low then you need more lift pump. At lift pressures that low you are hurting the high pressure flow and even risking damaging the high pressure pump itself (due to cavitation).

Easy way to gain more low side fuel flow is to voltage boost the pump when under load (boost in your case).

You are also likely out of fuel injector. What is your injector pulse width?

Is this gasoline or some other fuel?


PSS