How much should I pay for an LSD?

[jdehaan]

how much should I expect to pay for a used E30 M3 stock LSD? I found a guy wanting $400, but that seems really strong to me. Would you suggest an E30 diff, or an M coupe/roadster? What do you have on your cars? thanks

[Carstereopro]

I had an M Roadster diff built for my car by Diffsonline.com

Granted, they are only 20 minutes from my house.

I originally had the 3.46 open diff, and the car would hit the rev-limiter in every gear but fifth. Unitl I broke the carrier.... (too much power)

I had them build a custom 3.23lsd, and the car was fast as hell for the week I drove it, then I crashed it.

Cost me $1200. Including the installation, changing the bushings, swapping to 6 cyl half-shafts, and red-line fluid.

[andy]

I think I paid about $380 for mine from 002 Salvage in Hayward. It was a 3.73 though, in good condition. Add about $120 for a M Coupe style rear diff cover from ebay, and $40 for a solid bushing from Bimmerworld. Filled with M1 75W90, it didn't boil over after a long hot day at Buttonwillow. I've got just under 200 rwhp with my new engine.

The prices do seem to go up and down depending on what's available. The 3.73s are easy to find, 4.11's harder and the 3.91s darn near impossible.

[Carstereopro]

Originally Posted by andy

I've got just under 200 rwhp with my new engine.

I Dyno'd the car with the 3.46 open diff and was pulling 239rwhp, and 230ft/lbs.

The car was way too quick to hit the limiter, that is why I decided to go with the 3.23LSD, and not another 3.46 or 3.73.

After the diff swap I ran against an E46 M3, and from a dead start to 85mphish I was ahead, at 90-100mph even, and he began to pull away at 115mph (1 car length).

I'd probably gear lower if you have less power and torque on hand.