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RPM shift points vs MPH shift points

Posted: Mon Mar 30, 2009 1:25 pm
by 05silvycrew
On my model predator, U7193, I can change both the RPMs and MPH of the 1-2 shifts and 2-3 shifts seperatly. I believe I've added like 2 MPH and 1-200 RPM in the 1-2 shift, and about the same in the 2-3 shift. Here's my question:

If they're not aligned, which one does the computer default to in a WOT run? what happens if the engine achieves the RPMs but not the MPH or MPH and not the RPMs?

today I had to make a sudden move in traffic off the freeway on-ramp and the truck kicked down perfect, had great power, but got stuck bouncing off what seemed like the rev limiter. I had to back off the skinny peddle to get it to shift :shock: not a good thing trying to merge into 3 lanes of traffic!

Did the computer just get confused on which perameter to follow, or do I need to adjust the rev-limiter up another 100-200 RPMs?

RE: RPM shift points vs MPH shift points

Posted: Mon Mar 30, 2009 3:13 pm
by mikel
Here is how it works:

The MPH setting is the MINIMUM MPH that must be met before the PCM will command an upshift at the given RPM....so, if you just want to raise them, leave MPH alone and raise RPM.

Only time you need to do MPH is if you are lowering shift points, or you have added gears and the MPH/RPM correlation has changed.

Posted: Mon Mar 30, 2009 5:47 pm
by 05silvycrew
thank you sir! :D

So, my situation must have been that I raised the MPH upshift too high and the RPMs not high enough. I achieved the RPM shift point, but not the MPH causing the confusion in the computer. I'll go lower the upshift MPH back to stock and keep the RPMs the same.

Diablosport to the rescue once again!!