Quote:
Originally Posted by toast
All,
Other's experiences?
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Are you running stock injectors/fuel pump?
I too am on V25, fully tuned and running well. Setup is edelbrock/dBox/flex fuel/injectors/pump.
I have the exact same behavior you do, there's a slight dip in revs during most blips (or throttle tip in) before the revs "recover" and blip upward as intended. Like you've experienced it's most noticeable from idle, but I can notice it other places as well when blipping from a place of low throttle. It doesn't affect my driveability as I've gotten used to it, but it was slightly frustrating early on. Mostly because mid corner on track dipping into throttle can result in a VERY slight dip followed by a VERY slight "surge" in power -emphasis on slight. I've overcome this by a tiny bit of maintenance throttle in the corner if I need to modulate.
I had initially logged this blip behavior for Zach (and personally verified it could be seen in logs) and he wasn't able to tune it out. After dealing with it for awhile I began to theorize it may not be tune related but rather a mechanical nuance. My shot in the dark guess is when the throttle is blipped from idle (or low throttle input) the bypass valve closes as a result and the motor is now tasked with extra parasitic loss driving the blower all while having an intake plenum that's mostly vacuum. The slight dip could be the parasitic loss of the motor driving the blower before getting air in the plenum/engine (let alone boost) to assist overcoming the added resistance of the blower without a bypass. This empty plenum theory somewhat checks out in practice, when I give the car slight to moderate throttle and then immediately blip the "rev dipping" behavior seems to be minimized or non existent.
No idea if the above theory valid, but it makes sense given my limited knowledge on the subject. Hope this helps!