Throttle Surging

[ctuinstra]

While our car drives soooo much better after softening the suspension and a good tune, I still have a slight oscillation from time to time especially in second gear. Now that HP Tuners has stand-alone logging available, I pretty much log all the time now. Well tonight it wanted to do it again on me at a spot that I knew I could find on the log file easily.

Pay attention to the top row. The yellow is the TPS (Throttle Position Sensor on the throttle body). The white is the actual throttle pedal. You can see where I was bouncing the pedal and the throttle was following. Now the big question, which come first. I can always tell about the time it's going to happen. And is there anything more we can do about it in the tune? I still have a modified torque management (more sensitive than stock). I should put it back to stock and/or make it even less sensitive in the low torque demand range.

I always wondered if it had anything to do with the MAF, but looking really close at it, the MAF always lags the throttle. I swore the car drove the best when I was running old off the VE table (MAF disabled). I should test that again this fall when the weather is cooler. I thought this was interesting.

 

[Ross]

Your purple MAP line has a little bit of wiggle - I always thought the touchest point in throttle was when the supercharger bypass starts feathering in the boost, but I still sometimes get foot bounce at lower throttle. I haven't played much with the torque settings... I did try to set torque by gear - but the tables in HP Tuners must be for the automatics, as it doesn't know what gear my manual is in.