L76 G8 Advise

[LS1Silverado05]

Hey guys, I wanted your thoughts on a 2009 G8 with an L76... The car is basically stock. Ill be knocking some of the rust off my tuning skills on this car. I guess in short, other than fuel and timing, are there any other parameters that gains can be had in on a STOCK car with a stock calibration? (example: MAF calibrations etc?)

-My initial thoughts are some mild trans adjustments (6L80E)
-Disable the DOD
-Do a few logs and see if anything jumps out.
-Bump some timing and adjust fuel trims


I appreciate any thoughts. Thanks

[brandong007]

Remember one thing you said, "mild trans adjustments" with the auto. I got the truck version L76 in a vmax. I have tuned a handful of other GM cars and trucks, but this Gen IV is a booger. I haven't gotten to wideband tune on mine yet or played with virtual VE because I have a few mods on the way. My first attempt with reducing torque management was a disaster. I took like 75% out a a few other changes, and it bucked and surged, TCS light on, Stabilitrak error, so I started over and left 60% trans TM and quickened the shifts. Then I though I had most of the bugs worked out when I notice an odd dead pedal feeling on a startup unrelated to cold or warm with strange timing dips at cruise rpm's, higher partial rpm shift points above what was set in the tune, and when it was in this mode (which was not always the case), If you floored it, it would go into PE and WOT with correct spark, but would feel like a dog. It did so even though PCM would only allow throttle to partially open so I was getting all the timing, fueling, PE, and WOT but at a 40% blade opening. Get to a stop, plug in scanner, and problem goes away when I logged. I thought I was nuts, but knew something didn't feel right. It's like you told it you wanted to put a move on with the pedal, but you had to come to a complete stop before it would let you. As long as you were moving, It would do the same think no matter how much you punched it. I logged everything and determined it was Torque Mgmt Advance coming from Trans.

I battled for a couple weeks before realizing I forgot that I also changed the Transmission Torque Management-->Abuse Mode settings. I multiplied Torque Reduction and Duration by 50% chasing my tail on the other problem. Put those tables back to stock and runs great now...so relieved. I don't know that there is any benefit to changing those tables.

I also notice on these you don't have access to many of the VCM controls like AFR and Timing. You can only "reduce" timing with them which stinks. Also I wouldn't mess with throttle mappings. To me the Gen III is a cake walk compared to these PCM's. Somethings just don't seem to have intended affects. I also wouldn't mess with VVT...it's about good as it gets on stock cam. I did zero out the VVT advance for WOT cells so I have a much more consistent timing curve under WOT. I read so many posts on G8 L76 guys since there isn't a lot out on the VMax L76 6.0 and most experienced agree no performance gained using more than 24* timing even though they and my heavy Crew Cab will take 30* with 93. I want to track tune and test 22*-24* vs. 24*-27* since many claim high dyno numbers with the higher timing. I am actually gonna see if I can run my current timing with 89 (here it's 87/89/93) since we don't need 28*+ timing.

Good luck with the tuning and tip-toe around the trans torque management stuff.

[08 IOM G8]

Theres a ton of information over on the G8board for basics on the 6l80e. Also, on the basics of the tuning process. If your already familiar with HPT, then it should be a breeze to get through the information. Mine has been tuned MAF only using alot of bluegoats techniques with very little difficulty for over a year with no side effects even though I'm a beginner with the software. I've been able to fine tune the MAF and some of the timing and the car performs so much better than stock. The trans info is really useful. I had mine shifting really hard but i have backed up some (reduced too much of the TM nad shift times) and it seems to be alot better. Now that I've started to modify the car adding CAI, LS7 MAF and LT headers I'm having to learn even more of the processes. Good luck with it.

[jaydubb71]

^^^What he said. I basically learned HPT on my G8. Theres a thread over on www.g8board.com on basic stuff for the G8's. Look for Bluegoats thread. Its a sticky in the PCM section...

I have the same mods as 08 IOM G8 and my I used the same threads by Bluegoat to get where I am now.