best size diff for a diff swap to a '96 sport ti...

[rated///M]

Just wondering what you guys thought would be a would be good for the kind of driving I expect to be doing in this car: some HWY(dont want to destroy my top end though) - definately want to improve low end though - something tame enough for daily driving, but something that's gonna help on the occassional autox/DE.

TIA

[1996 328ti]

Before you do mods for autocross, consider what class you will be in.
In our chapter each class has stock and mod. SCCA have many classes also. If you just want to do it for fun, that's a different story.

[rated///M]

yeah, i thought about that also...most of the autoxing i'd do would be for fun though.

is 4:10 too high?

[1996 328ti]

I know there is a chart somewhere that shows how your speed changes with RPMs using various diffs.

I have a 3.46 Quaife in my 328ti.. The engine is revving pretty high in 5th on the highway. t's not that annoying but I wish I had a 6-speed. At the track I'm guessing I'm hitting the rev limiter at 85-90 in 3rd and 110-115 in 4th.

I'm sure someone will chime in.

[rated///M]

yeah, this sounds great...unfortunately i'll be down 2 cylinders, atleast for a while :twisted:

[kiley_sean]

Hey, steve, did you install the Quaife into your stock small case diff., or are you running an Mcoupe/Mroadster subframe w/ the quaife? If the latter, where did you go about picking that rear subframe?

Thanks.

[1996 328ti]

Quaife no longer make a small diff although it is in their catalog. I'm using the medium diff for 6-cylinders. The subframe is the same in my case. Only changes were the halfshafts. I do have the MCoupe cooling cover though.

[kiley_sean]

What tranny are you running, and I am guessing that you had to change out the output flanges on the diff. ? I heard the the quaife holds up to some hard abuse, how is your experience with it? Thanks.

[JedzE36/5]

http://www.368s.com/tools_rpm.phtml?PHPSESSID=5af159a2085f1fcb93f620dfc2944bf3

here is an RPM tool.