Beginner G8 GT trans tuning

[bluessv]

Hey guys,

This attached tune is the most current for the Holden Commodore SS auto (Pontiac G8). It is very different to the early ones but I think I've mentioned that before.

I have used the new settings in the OnComing/Offgoing Pressure Preset, the slightly different Oncoming Volume Preset for the 2-3 shift, the different Shift Time Transition for the 1-2 and 2-3 shifts and the slightly different Desired Output Torque tables. I've kept the original TM settings, shift pressures and Discrete Shift Torque settings...in fact all the original settings except those mentioned above.

In short, the trans shifts a lot better, cleaner/crisper shifting. I like so feel free to experiment and tell me what you think?

[bluessv]

bump...bump...

Anyone had time or bothered trying out these new settings?

[informationjunkie]

when the roads get clean again i might give it a try, but that could be a while

[Allmachtige]

I loaded a tune very similar to shane's right before the snow fell. Now I never get above 3,000rpm...not until April or May.

[04blackgmc]

I loaded a tune very similar to shane's right before the snow fell. Now I never get above 3,000rpm...not until April or May.

how you liking it?

i made a Few tiny changes had the car out a few times with headers.. weather is cold cold heh..

[memphiss13]

I am tuning a G8 GT that is really giving me problems. Just for a little background the car has a 228/240 cam, longtube headers, and a yank 3200 stall. It makes great power and the upshifts feel great after a little modifying. On the 6-2, 5-2 downshifts the car is pulling alot of timing, down to as much as -11.5*. Ofcourse this causes the car to have a major delay and sputter until the timing comes back. I have searched some of the threads on here and have pretty much tried everything. Neutral down skip is disabled, flare tq mgmt is all set to none, etc...

I've attached my tune file as well as a datalog from the street. This is the last thing I have to work out on the car so any help is greatly appreciated. The car runs great otherwise, except for a decel idle surge that I'm trying to get worked out

[8850]

I am tuning a G8 GT that is really giving me problems. Just for a little background the car has a 228/240 cam, longtube headers, and a yank 3200 stall. It makes great power and the upshifts feel great after a little modifying. On the 6-2, 5-2 downshifts the car is pulling alot of timing, down to as much as -11.5*. Ofcourse this causes the car to have a major delay and sputter until the timing comes back. I have searched some of the threads on here and have pretty much tried everything. Neutral down skip is disabled, flare tq mgmt is all set to none, etc...

I've attached my tune file as well as a datalog from the street. This is the last thing I have to work out on the car so any help is greatly appreciated. The car runs great otherwise, except for a decel idle surge that I'm trying to get worked out

Here's what Chris posted a few days back. Have not tried it myself.

TCM uses aggressive tqmgt to prevent engine flare while the trans is in neutral. It can be turned off by:
- set Neutral Down Skip, Disabled
- Speed Ctrl Terminate, Immediate

Also set Limit TqMgt Enable Temp to something high.

[memphiss13]

yeah I read that post yesterday and thought it was going to fix my problem for sure. it had no effect on it at all.

[Allmachtige]

how you liking it?

i made a Few tiny changes had the car out a few times with headers.. weather is cold cold heh..

So far so good. Only difference I can remember between our tunes is I have discrete shifts disabled for 1-2,2-3.

What changes have you made?

[04blackgmc]

I re enabled mine a few tunes ago

[bluegoat06]

Wow, Lots of great info around, didn't pay enought attention cause i didn't have an A6 equipped car that was mine before. 04black, i took your trans settings from your headers v1.5 tune, and i'll give it a try on Tuesday. the only thing i left the same was the 200 max adapt volume for the 1-2,2-3 and 3-4 shift. now i'll have a lot more time to experiment with this transmission...

[04blackgmc]

Wow, Lots of great info around, didn't pay enought attention cause i didn't have an A6 equipped car that was mine before. 04black, i took your trans settings from your headers v1.5 tune, and i'll give it a try on Tuesday. the only thing i left the same was the 200 max adapt volume for the 1-2,2-3 and 3-4 shift. now i'll have a lot more time to experiment with this transmission...

ahh man congrats!!!

yea thats the tune i have in the car still and prob be in the car for a long time

i just wish the weather wasnt so bad around here now car is sittin in the garage now

[bluegoat06]

Thanks a lot man, it's really a great car, and even better Trans
And tell me it about it, i'm going to clean my driveway rigth now, gosh i hate the snow. I prepared the tune file i'll be uploading tomorrow, most of the trans stuff came with what i saw in a couple of your tunes, i think the difference is that i still have a little more time in the shift torque adder or shift time transition i can't remember, it's been a long day trying to digest this thread as well as the other big one around.

[ecuboss]

Has anyone studied /comparied a Cadillac CTS-V 6L90 tunes?
My thinking is that they have to cope with alot more power out of the box.
A quick compare of the stock tune against my stock tune shows that the desired shift times are all set to zero! Other points of interest is that the max adapt volume for 2-3 is set to 50. I have personally been using 60 for my 2-3 max adapt based on the fact that every single stock tune I have seen all use 40 and I'm not convinced that GM have got that wrong on so many different models of car.

[Allmachtige]

Has anyone studied /comparied a Cadillac CTS-V 6L90 tunes?
My thinking is that they have to cope with alot more power out of the box.
A quick compare of the stock tune against my stock tune shows that the desired shift times are all set to zero! Other points of interest is that the max adapt volume for 2-3 is set to 50. I have personally been using 60 for my 2-3 max adapt based on the fact that every single stock tune I have seen all use 40 and I'm not convinced that GM have got that wrong on so many different models of car.

Well some tunes (the tuning guide people) actually increase a lot of those offset/onset pressures.

GM did probably set 2-3 adapt volume to 40 for a reason, but I'll put money down that its a setting "for the masses". They are trying to appeal to the older as well as the younger crowd.

BTW I wouldn't bother with comparing to another transmission. Hell, just comparing to a 2006 A6 Corvette put me through a month of tuning torment. I find its best to stick with what you got and compare to other tuners with the same exact car.

[LSX378]

Our understanding of the adapt volumes, is that if the trans needs to use numbers higher than what is preset here, it will raise a DTC that indicates adapt volume is out of range.

So if the number is increased, it simply means that excessive clutch wear will not be picked up as early. The trans after all needs to know when its on its last legs so it can raise a red flag .

[bluessv]

LSX378,

That was my understand of those numbers too. And with that in mind I've always just left mine alone. At one stage I thought it was making a positive improvement to my 2-3 shift but turned out it was only disguising a failed tower seal in the box.

[ecuboss]

BTW I wouldn't bother with comparing to another transmission. Hell, just comparing to a 2006 A6 Corvette put me through a month of tuning torment. I find its best to stick with what you got and compare to other tuners with the same exact car.

I was looking at the tune more to understand how they can make the box handle more torque than the 6L80 - rather than using the parameters directly.

[LSX378]

I was looking at the tune more to understand how they can make the box handle more torque than the 6L80 - rather than using the parameters directly.

6L90E handles more torque as it has a much larger output shaft, additional sun gear on the output stage planetary gear set, and some extra clutch plates. Lengthens the case an inch and a quarter or so.

[Allmachtige]

Our understanding of the adapt volumes, is that if the trans needs to use numbers higher than what is preset here, it will raise a DTC that indicates adapt volume is out of range.

So if the number is increased, it simply means that excessive clutch wear will not be picked up as early. The trans after all needs to know when its on its last legs so it can raise a red flag .

So why would the 2-3 max adapt volume be so low (40) compared to all other shifts (200)? Poor 2-3 clutches?