Originally Posted by BR3W CITY
I'm gonna toss a tune issue into the ring....I know you guys love it when I say the problem is in the Magic Box. This is my experience from the 4l80e
Going down the road at 65 at like 1800rpm, all of a sudden, it seems like your giving 5% more throttle, a few hundred rpm's, but the SAME speed.
This is actually caused by a few things, one of which is the lockup speeds/settings, another is "abuse protection" (bet you've never heard it referenced before), and the last is issues related to pedal postion %. Its gonna be hard to articulate, but I'll try.
Basically, the gear changes/lockup can be adjusted on a table of speeds. If any of the speeds fall out of a reasonable range, it can attempt "permanent lockup" in which the VSS will never see its "top" speed. The pedal position comes in when you have issues like IAC-crutching. This is using dbw throttle % to give a smoother idle, after you've maxed the IAC setting. You also tend to see really "bumpy" power graphs. Both are signs of lazy/inexperienced tuning. We are currently battling some major tune issues, and I'll be able to give you a better idea of how it can be handled next week*
*we've pretty much given up an allowing anyone to tune my truck, aside from a few very special individuals. Call me an elitist, but when I have the guy who designed the LS1, along with another guy who designed MAST's tuning system, telling me I'm doing it wrong...I listen. Those two have nearly 65years experience, and are working with my a friend and I on a few projects. They are also helping us offer tuning on the side, so I'll be able to offer more to you guys here as time goes on.
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