I have posted a few times about my 2009 Dodge Challenger 6.1 Auto which has an Edelbrock E-Force supercharger.
Ever since I installed the S/C several years ago, I've noticed an odd behavior from the car. Car runs great for WOT, but for mild part throttle acceleration, there is an issue. Under mild acceleration from a stop, let's say accelerator pedal position is held steady at around 1.3V and TPS at 1.2V the car accelerates slowly, around 86kPA on the MAP for example, say 20MPH and climbing, I notice that there's a point where suddenly the TPS unexpectedly ramps up to 2.8V, the MAP goes up to 100+kPA accordingly (note: the pedal hasn't moved, still at 1.3V)...so clearly the throttle blade has opened a large amount, enough to increase the air pressure in the S/C intake throat which triggers the S/C bypass vacuum operated actuator to extend, and close the bypass valve and put the S/C into full operation, and thus the manifold is essentially into full boost thru the S/C. The timing pulls way back (I suppose that's a VERY good thing) otherwise the car would produce allot of torque and accelerate unexpectedly. There's nothing dangerous about how the car behaves, but the part-throttle behavior is sluggish and difficult to manage with the accelerator pedal.
I've read some posts about issues with tuning HEMIs and bypass valves, and issues that the bypass valve is essentially not under our control. It would seem that we should have control of the throttle position, albeit indirectly through the pedal input, but I can't find how the tune controls the throttle position actuator or which variables to study. One post I read talks about pedal input = torque demand, which is sent to another lookup to find the right pedal position, but it was for later model HEMI's and mine is the older NGC4 controller, so the info in that post was not similar enough for mine to give me enough help to figure out how to adjust mine.
My question is, is there a problem with the tune? Is there a fix? I only notice and get annoyed, because I have a very similar setup on my Chevy SS 6.2 LS3 with Whipple, and there is no non-linear behavior on its throttle position like this at all.
log file attached, see time marker 07:33 for a pretty good example of the TPS deviating from pedal position.
Thanks so much, in advance, for any assistance.
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Originally Posted by PurpleRam
