My vehicle is a 2012 Tahoe, compared to a 2015 Tahoe and 2018 Silverado tunes.
I'm sure the OS's are different, as I cannot directly compare all maps, but many look similar.
Daily driver, so I'm just looking for it to shift smoothly with less bogging. (3.08 gears)
The updated downshift schedules helped GREATLY. Original tune was waaaay too lazy.
One other thing I used to notice is a rear end/driveline clunk when letting off throttle and it's shifting to 3rd.
Sort of hoping new tune might address this.
Does anyone have suggestions on what to change and what NOT to change?
Here is a list of 'updates' I am testing.
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shift schedule - works fine of course, newer scheduling much better and helping speed up my own tweaks...
CT downshift - modified gradient, possible refinement (2017+)
inertia factor profile - same maps scaled down to 6000 rpm, 1-2 and 2-3 shift had some 8,9 cells replaced with 7. Softening mid-high parts of the shift??
upshift torque adder - same maps scaled to 6000 rpm (instead of 6250). 1-2 and 2-3 look like they have been refined, others exactly the same.
downshift torque adder - similar maps, some more tweaked than others. More changes than the upshift adders.
upshift transition times - similar to stock, some increases, some decreases.
*desired output torque factor!! - 1-2, 2-3 maps have been zero'd! 3-4 was all 0's, now has a ramp. 4-5 got tweaked a little.
*base downshift pressures - significant increase in ONE row, upto 300% over original values, seems to be within operating range, no axis labels.. lessen downshift time?
*adaptive volume and pressure - pressure presets roughly similar. 1-2 and 5-6 volumes were originally ~double the others, those values were halved. Hardware change or compensated by other maps?
torque management cold modifier - seems to have been refined, graph is smoother, just for cold temps
*torque mgt. upshift adder/modifier - had 1's in original adder, now 0, modifier had some lowish negative numbers at low rpm/torque, now zero's...
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Also wondering how much the TCC strategy might affect the shift tuning.
Original tune would sometimes unlock tcc before shifting, whereas the new tunes seem to stay locked during shifts.
OEM 2012 tune 2012Tahoe-T43.original.hpt
'updated' tune 2012Tahoe-TCC123off.15shift.15slip.18inert.18time.hpt
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Update: Drove around the block with all changes. No obvious difference. I've reverted to original for the '*' tagged changes.
For some reason I felt like the new inertia map and torque adder changes may have felt better, so will leave the other changes for now.
Datalog with all changes Log-0032-1GNSKBE0XCR266687.hpl
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Update 2: One thing I found, when using the 15+ TCC apply/release strategy, it would keep the gear engaged despite shift tables saying it should downshift.
(when tcc release was below downshift speed) I incorrectly believed the shift tables would override the TCC setting.
Should be fixed so shifts happen when they are supposed to..