Shift Quality

[cleatus12r]

Ok here they are, in no particular order.............

Bill, I am not saying that these tunes are perfect so if there is something amiss, then please feel free to offer suggestions. These do work very well for me and the way I drive though.

[907DAVE]

Thanks Cody, gonna have to study and compare these. I did not know anything about the "torque table" but will have to look at that, and I was wondering what that was for.

[907DAVE]

I wasn't thinking straight about the torque reduction map. I had it in my head that it was part of the shifting strategy, when it was really just a map for how much power was "taken away" during a shift. I think I will have to agree with your way of looking at it Cody, if less power is being sent through the tranny while shifting, the less wear/stress there should be(at least I think that's what you meant). I would like to hear why you two disagree with each other on this.

Why not go beyond stock and increase the reduction even more for a heavy tow program?

(on edit, that exactly what it looks like you did)

I would assume the issue would be with keeping the turbo "lit" under heavy load and with such a great reduction it might be easy to get under the turbo, but the tranny would be pretty happy, but I am just assuming and we all know what that makes out of you and me.


Think I am going to have to start from scratch on this one.

Thanks Cody

[Power Hungry]

On the power reduction, many folks complain about the "dive" when the truck shifts and prefer to have the torque reduction removed. On some performance programs, we eliminate the torque reduction, but on tow programs we don't... for obvious reasons.

As for the Shift Slope and Offset, here's how it works:

The PCM calculates a specific amount of torque output based on the calculated torque table. Let's say this is 372 Ft./Lbs for a given Throttle Position and Exhaust Backpressure.

You multiply the torque by the slope for that particular gear to generate a Line Pressure PSI value. Using your towing (1st program) example above and assmuing 2nd gear...

372 * 0.1719 = 64 (63.9468) PSI

Then you add the offset...

64 PSI + 0 PSI = 64 PSI

64 PSI is what the PCM will set the EPC regulator to for main line pressure in that particular gear.

Make sense now?

[cleatus12r]

OH MAN does it ever make sense now!

Which is why adjusting the torque table map makes such a difference in pressure all by itself.

Thank you Bill.



I hope you had a good evening and that you and Corey as well as the kids have a great start to 2010!

[Power Hungry]

Glad to be of assistance. You and Jess (and the horses and "Dinner" and the rest of the brood running around on the farm) have a fantastic New Year as well. May God bless you and provide everything you need.

Take care.

[907DAVE]

How much does the Adaptive Shift Strategy's play into this?

What all does it change, just shift pressures?