Hello all,
I'm thinking of how to get a higher rear gear, but I know I won't want to stay with a high gear all year, so I am thinking of buying a used 2.73 C5 unit from an automatic and putting in a 2.93 gear (if I can find it) and then swapping back and forth over the year events from my stock C5 Z06 3.42 gears to this higher carrier. This way I can attempt a higher speed run at Texas Mile, then come home and swap them back until the next event (which is only twice a year, spring and fall). this way I won't have to keep paying someone for the gear change, I can pop it out and pop the other one back in.

My question is around this:
1- Since the carrier I will end up picking up is most likely from an automatic car (I don't know of any 2 series carriers that came with a manual) and I have a manual, do I need any other parts or are the carriers the same to simply swap? I understand there is a plate of some kind on the automatic carrier, I'm wondering if that is an adapter and I simply leave it off since I am connecting to a manual.
2- Because there is a gear change, I know on an automatic it would require programming, but do I need to do that on a manual setup? I forget how the speedo works and gets it's numbers.
3-Is there anything else that might need adjusting because of the change?

I'm looking at this as it seems easier than mucking around trying to get a super tall tire under the car. I can probably swap a diff in a weekend even if I take my time, and switching back and forth doesn't seem that bad.

Guidance and thoughts?

Thanks.

 

Tied to the above question, does anyone know where I can get a 2.93 rear gear, I don't see one listed by GM but perhaps someone else like Motive makes one?

Thanks

 

i could be wrong, but i think the VSS counts revolutions of the transmission output shaft, so the pulses per mile would need to be changed in the tune.. but if it's only being used a couple times during the track events, i don't see the harm in simply mathing out a cheat sheet of equivalent speeds to drive to your event & back. the odometer difference won't be that far off for how little it's ran that way.

 

Im with this. So if its wrong u wont be alone.

 

The VSS measures at the drive axle not the tranny, no affect on the speedometer. Only a change in tire diameter changes the speed. Auto trannys require a tune after a gear ratio change. When I went from 3:42 stock gears to a 4:10 rear gear nothing changed in the speedo. Changing to 19in 305s in the rear did

 

going from 2.73 to 3.42 does require reprogramming of the transmission shift points.

 

fair enough - i couldn't remember for sure if the vette was on the output shaft or the axle. i know for sure my GM truck was on the transfer case's output shaft.

 

and he's said a number of times he has a manual trans (for the folks talking about retuning shift points)

 

Thanks, yes, as a manual then I was verifying I didn't need to change.

OK, then I'm on the hunt for a carrier. It seems that an auto or manual carrier doesn't matter, I just remove the auto adapter plate since I won't need it.

Any guidance on where to get a 2.93 gear, I still cannot seem to find one. Maybe they only make that for a C6 ?

Thank you everyone!

 

They require a tune, but not for the speedo. On A4 C5s, the speedo accuracy doesn't change, no matter what gearset is used. Hope this helps.....