To make a long story as short as possible my 2009 G8 has a fairly large cam / e85 tuned - Just installed a larger stall up to 3800 form 3400 previously. Complete fresh rebuild on the 6l80.
Rebuild was necessary because a highway pull completely trashed the converter clutch and 4,5,6 were pretty trashed and coned. The old trans had downshifting issues above 40 mph. It seemed to not like to downshift above that speed. I believe that is all in the tune, but no clue where to look.
Current Build- NA G8 making 480-500 RWHP
- Fresh Converter Refresh and update to 3800 stall speed
- Fresh 6l80 Pump
- Sonnax Zip Kit
- TECHM pressure switch rebuild
- Reybestos Red Clutches for 1-4 w / Billet apply piston
-Reybestos Red Clutches for 4,5,6 with Lindered steels - Sonnax HD piston
-3,5,R - Alto G3 clutches with Kolene steels - Sonnax HD Apply piston
I used the Blue Cat tool to adjust shift times and WOT and partial throttle shifts seem to be fine and quick and not overly harsh.
Issues
Main Issue - it just doesn't seem to want to down shift properly at almost any speed
Minor Issue - After cruising for a bit it then coming to a complete stop, upon taking off again it sometimes has slight popping (small backfires ?) under light throttle
Minor Issue 2 - It seems to lug a bit above 35 mph in town and between 50- 55 on the highway
Any help would be greatly appreciated
G8Current.hpt