trans tuning advice on g8 gt with 3.45 gear swap

[chevelle1511]

want to see how much et i can drop with 3.45 swap on stock car. my g8 is almost stock, have a cai and removed speed limiter an tq management, still running stock fuel and timing. last night swapped in a 3.45 diff so now have to play with my shift points. tryed it with the 6200 for the stock gears and it was a dog. set them to 6500 and seemed to pull alot harder. just wondering what other people are running... any suggestions would be appreciated.

[bluegoat06]

Your shift rpm would stay the same, the cam is so small in the G8's in stock form, that there is really no point in going higher than 6000-6100rpm with your mods. what you need to adjust is your shift mph, they would lower with respect of what you have with the factory 2.92 final drive. in the G8's, both shift mph and shift rpm have to be really close to each other.

There is a calculator from Bluecat in this section that would help get close to where rpm and mph need to be, i've found the 1-2 shift is 2-3mph lower than what the calc tells you to use. but you need to experiment with the shift mph to make it jive with the rpm eitherway.

Good Luck.