GMPP dyno results, not impressive AT ALL

[I1ULUZ]

OK, Saturday I left my laptop on the rack by the dyno where I was data logging the car during the runs. Got it this morning and downloaded the GMPP file.

No DTC's are set. I compared the files between stock and GMPP tune, there are changes. So I am sure the flash took. Now if GM didn't make all the changes to the 2009 program I can see it acting like a stock tune.

I have an appointment Thursday morning for the tech who installed the tune to call GM and see what he can learn.

Also I am about to call GM Customer Service line and see what they say. I am betting I reach a bunch of clueless people till I reach a engineer, IF I make it that far.

[ChgoBlues]

Originally Posted by JeffInDFW There is a pretty long thread here on the forum where everyone talks about the following....I am going to paraphrase from MEMORY, but I'll get the basics right. Hopefully, someone can point you to the thread... You and I both know that the ECMs learn up when you do mods, but supposedly, the GMPP tune is the most severe about this. Basically, when you first get the tune, the ECM starts out at the most conservative settings. If the ECM does not see any knock, then it remembers that when you turn the car off. When you "key cycle" the car by starting and driving it again, it makes ONE step up in agressiveness in the tuning. It does this each "key cycle" until it reaches its most aggressive tuning OR it sees something that tells it to pull back. It pulls back very quickly, but steps upward slowly. Each "key cycle" can not be just starting the car and turning it off. It has to reach operating temp for a certain time frame, etc. The last I saw in that thread, the general thinking was it took 10-12 "key cycles" for the car to reach max performance. The people in the thread were very convinced that this was a bigger issue for our Kappas than other ECMs which also basically work like that. Now, all that said, I am floored that you only saw a freaking 1hp gain. 1. I've got the GMPP tune in mine (with a stick), and its a good 30hp on the butt dyno. Good luck....

Jeff, think you got it pretty good.. And IF I recall Flash's Owner's threads too, yes the 10-12 ignition cycles is very key to the learning process here.. It's not just a matter of cycling the key 10 times but actual driving cycles where the sensors have to read and adjust on the new way the ECM is reading info...