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Thread: E85 & Nitrous & Returnless Fuel System

  1. #1

    Default E85 & Nitrous & Returnless Fuel System

    I have a '05 Pontiac GTP that I run E85 as my primary fuel. I have looked around and haven't seen anything about jetting for E85. My car is supercharged and has a returnless fuel system fixed at 65 psi. How does this effect tuning? The last thing I ever used nitrous on, was a plate system on a SBC. Thank you, Jeff

  2. #2
    Join Date
    Nov 2013
    Chicago IL


    Well, quite simply put, call the place you bought the nitrous stuff from, they can tell you what the jetting should be.

    The returnless fuel system is a BAD idea with Forced Induction. The big problem is that as you make boost, fuel pressure needs to rise along with it to compensate for the boost pushing upwards on the injectors (it's called Delta Pressure). What ends up happening is you need a LOT more fuel at WOT than you should need, which means you need bigger injectors than you should actually need, which means more chance of running out of fuel pump or running out of injector or both.

    And with a returnless system, you often can drain the rails with the closest injectors and the furthest ones away starve for fuel and you have lean cylinders. So you run more risk of detonation and torching a piston/heads on the cylinders that are farther away from the regulator.
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