Just wondering here... has anyone bothered to chart the output of the voltage from the pedal to TPS?
I used to make ETC pedals in a former life... I'm guessing the "lag" everyone is complaining about is related to the slope of the resistors in the pedal. The pedal acts as a potentiometer (think rotary dimmer knob for house lighting). You can change the slope of that potentiometer to adjust the output voltage of the pedal vs. distance (angle of pedal actually) of pedal travel. Meaning... you can get 10% of travel and 10% throttle, or 10% travel gives you 5% throttle. So... one can make the output fit what they want based on pedal travel.
In order to see what the pedal is doing, you'll need to map the voltage vs. TPS and determine the slope. I'm curious if it's constant or varies through travel. I'm guessing the SprintBooster simply takes the pedal output voltage and creates it's own output for the ECU to see? If so, they simply mapped out the pedal slope and force out a different output than the pedal would give (ie. report 3.8v when receiving 3.2v).
I think this can be fixed by tables in the ECU, *if* you can find the table that understands pedal output voltage and relays that to the throttle plate... but I'm not certain what all would need to be changed. I never got to play on the ECU side of that sub-system.
From what I've learned from engine tuning, it's not nearly as simple as adjusting the throttle position. From what I've been learning, and from what I've read from I think it was GMtech, there's a lot of stuff going on behind the scenes, even after you've been playing with tunes that can easily beat the GMPP tune. I got it to a point where it was making good boost/power, but delivery was shit. It was dead till about 2100rpm, then came on like a freight train, and between 2200-3500rpm it was harder to control/modulate than it was before I started upping the power.
As he mentioned in a very important thread something along the lines of "most important table", playing with this can do a lot of removing lag. For example, I used to find it difficult to accelerate hard from a dead stop into a left hand turn with good throttle control. It would simply want to blow out the rear tires, or if I came off the throttle even just a hair, the boost would drop off. I've been playing with some of these tables, and I've gone back to no cat warmup (did it as a favor to my neighbours on cold starts up early in the morning, but went back to cat warmup while I was fine tuning the tables, so it wouldn't run rough right after start up), and I'm finally starting to get things dialed in a little. Although I've been getting this weird wastegate issue when I pull away with a cold engine. Seems as though the wastegate is shut, then wants to open, because it doesn't want to get on the boost, but is too slow to do so. Doesn't really change the power delivery, but I can distinctly hear the turbo spool up, only to vent, and only when the car is cold, and accelerating from a dead stop.
