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Thread: Injector Duty Cycle 4.0L Biturbo platform

  1. #1

    Injector Duty Cycle 4.0L Biturbo platform

    Does anyone know what the injector duty cycle is for the DI injector used in the 4.0L platform?

    This injector (MB PN 256-070-56-00-80) is used on multiple engines including the AMG GT where my interest lies.

    The GT comes with multiple levels of performance output using this same injector:

    The GT is about 469hp
    The GTS about 503
    The GTR about 577

    So, I imagine fueling varies and that would mean different duty cycles for the same injector. For the most part, the differences BT the GT(469hp) and GTS(503hp) appears to be only a 0.2 Bar increase in boost.

    If anyone knows the duty cycle at any level across these variants, or all 3, would appreciate it.

  2. #2
    Advanced Tuner
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    I bet they may peak at something like .2bar diff, but I bet the GTR holds more boost up high.
    Like two cars making 400ftlbs Tq, but one makes it only at 2200rpm and drops to nothing after that, the other one makes it from 3-6k. The latter will cream the former and make more than twice as much horsepower.
    So my guess is they may peak the same or close to it, but at higher rpm the boost has dropped more on the GT while GTR. Have to slow the one car down if you want to sell the more expensive one, right? Tinkering with boost is the easiest way when it's just a few clicks of the mouse.
    I'm also betting inj duty cycle has nothing to do with it, I bet it simply changes with the boost difference, maybe a bit richer up top. I know my car was very lean up top oem.

    Can you post your oem file for me? I'm curious to see what's in there...
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909