6l80e 1-2 shift too harsh, tune attached

[cjg454ss]

How do you soften the 1-2 shift. i have a 2010 silverado A6 4X2, i went through the threads and got it perfect except for 1-2. i even changed the cold multilplier to 0.500 instead of 0.250. 2-3, 3-4 is awesome, 1-2 gives a little shudder or something just not clean.

is the shift torque factor modifier adder something to lessen just the 1-2? I would like the cold mulitplier at .250 because it works the best, just 1-2 seems too harsh.

i attached a log and my current tune. Let me know what you guys think. I went through all the thread read for about 2 weeks and did a complete tune on my new truck. what a difference from stock. the file also may be helpfull for other truck guys in the future.

Chris

[bluegoat06]

I'd put the cold multplier back to stock, and play with the adder modifier (using -values), and shift torque and shift torque adder until you find the values you suite your needs.

The Final Torque Factor is calculated like this:

FTF = {Shift Torque Factor + (Shift Torque Factor Adder * Shift Torque Factor Adder Modifier)} * Torque Factor Cold

Shift Torque Factor is per shift

Shift Torque Factor Adder is per shift, it is multiplied by the Shift Torque Adder Mod before being added to the Shift Torque Factor.

Shift Torque Adder Modifier is a table with RPM & Driver Demand Torque. It is used to scale the Shift Torque Adder depending on RPM/Demand Torque To give the different shift feel.

Torque Factor Cold is used to account for cold trans temp.

An example of my adder modifer table (cold multiplier is stock)



Hope it helps.


Also, i wonder what GM did with the shift time values for upshift/downshift, special and what not in the trucks, i guess is all embeded now in shift inertia profile and shift time torque adder ?

[bluegoat06]

Aso, this excel spreadsheet should help you calculate the amount of TM left depending on what you set in the shift toque, shift torque adder and adder modifier.

Note: this calc doesn't include the cold multiplier. in my case, the trans won't see -20F oil temps, and i have 1's from -4F and up, so it doesn't add/remove anything from my trans TM, and thus i don't do anything with the cold multiplier in the calc.

[cjg454ss]

thank yo ubluegoat.... What did you think of the other parameters. i made those changes and will try it tomorrow. Thanks again

[C5pilot]

Another idea might be to lower 1-2 pressure to make it a softer shift.

[cjg454ss]

Another idea might be to lower 1-2 pressure to make it a softer shift.

i tried that numerous times, even lower than stock and it did not soften the shift. I loaded it on the way toi work and it felt really good. might soften it a little more at wot. only thing is i still get the timing drop for 1 second on the down shift. Cant tell if its burst knock of what. any information on this.

[Rickym]

Hey Chris would you still happen to have to tune file for the 6l80e?