Hey guys, i've got a 91 RS and i was looking for quick ways to make some acceleration improvments. The first thing that i wanted to do was get new gears for it. I was wondering if anyone had some suggestions. Its just going to be a regular daily driver so it wont be going to the track or anything. So suggestions on what ratios i should get and where i should look to buy them from (junkyard or ebay or something) would be appreciated. Thanks in advance

 

I'm on the same hunt. Here are the options I've found:

1. Junkyard rear end. Look for the car with the rear end gears you want. Unless they know what came on the junked car I've found it hard to determine what the gearing is. Maybe someone will chime in with a good way to determine this.
2. New gears, same carrier. If you already have a series II carrier, you may be limited to 3.08. Series III will go up to 4.10 (I think) and series II will go up to 3.08.
3. 4th gen rear - For me, this would mean new brakes too which I am all about (drums to disk). The wheels may stick out a tad more on each side but so what?

Be careful on which one you decide on. It's been said that parts are hard to find on the 9 bolt Borg-Warner rears although the gearing is attractive at 3.27 (came on GTA's/TA's). Also, if you look at a used rear end that had a lot of mileage to begin with, you may have plenty of parts on it to replace (think rebuild).

I hope this and any corrections/additions that follow help.

Cheers and welcome to the forum!

~C

 

If you can jack up the rear and have a friend.. put a piece of masking tape on the drive shaft facing straight down. Take your finger and put it on the top passenger side lug nut.. spin the wheel slow..
Now say the car has 3.73's.. the drive shaft will spin exactly 3 times for that 73% of one turn you did on the rim.. think of the top lugnut as 0% and if it goes all the way around back to the top thats 100%(it won't).
So basically you keep track of how far that lugnut turned as he counts the drive shaft turns.. and now you know the gear ratio.
Give it a try on a car you know the gear ratio of a few times to get the hang of it.

 

Thanks guys, im pretty sure i am gonna find one out of a 4th gen in a junkyard, thanks for the tips