'12, '15, '17 Tahoe 6l80 3.08 shift schedule comparisons.

[mikez71]

had to tweak some 0% 2-1 downshift and 100% 3-4 shift to get the graphs to be on the same scale.
So one number in each graph is wrong the lighter cells (8.14, 97.29, 97.29)
The actual number is in the neighboring cell.(8.28, 95.94, 95.01)

2012


2015


2017

 

[Marky Dissod]

?

 

[mikez71]

updated!

Might add 5th and 6th, but they aren't as fun to look at without all the gears being on the same page..
Maybe I will copy them into the 1-4 tables so they can be viewed together..
(2013+ tunes layout has 5th upshift, 5th downshift, 6th upshift, 6th downshift on separate graphs, hard to see interaction)

 

[mikez71]

Took it for a drive..

I kind of like the 2015 pattern more for puttin' around.. Might blend em a little.
2017 isn't bad.. just feels like a little bit of tow mode on light throttle..
more aggressive, but revvier in the low gears.. winding out a little more at spots in the 1-2 and 2-3 for cruisin..

If I want performance, I'll activate tow mode.. (which can also benefit from tuning I'm sure)

I'll drive it some more, but I have a feeling it will be something between the 15 and 17 tunes for me..
----------------------------------------------------------------------------------------------------------------
Update: it's growing on me some, going to drive it a good week before I tweak anything..

 

[mikez71]

The 2017 map revs a little high in places before shifting.. Hangs a bit. Low end and top end.
The 2.5mph increase before WOT 1-2 shift and 2mph increase before WOT 2-3 shift feels too much.
Interestingly, WOT 3-4 shift is about 3mph lower than the original tune.
(Haven't gone that fast yet... despite disabling speed limiter!)

It also causes me to modulate the throttle a little more at low throttles..
As the rpms plateau at low throttle, you depress gas pedal, making it rev out further up the map, it shifts,
now you're at a higher throttle angle than you wanted to accelerate at. Ease off accel pedal.

CAVEAT: I have my TCC off in gears 1-3. Being a different series engine comparing my 2012 to a 2017,
differences in the spark map/power output probably also affect shift scheduling.

HOWEVER, I was very satisfied with the 2015 schedule out of the box.
While the 2017 map is noticeably less laggy, it just does not shift as smooth or feel as natural as 2015.

Worth attempting to blend the two.. So far results are positive.
Here's the current state of tune for anyone else with a 5.3/6l80/3.08


Noticed the 2017 3.42(silverado) vs 3.08(tahoe) shift scheduling curve is identical, essentially scaled 10%.

2017 silverado 5.3 3.42


2017 Tahoe 5.3 3.08