Diff is shot - advice?

[monkeyodeath]

The open diff in my 325i is on its way out and the bearings are starting to whine.

I'm thinking this might be a good time to replace it with an LSD.

It'll be mostly for street driving, no auto-x or drag racing at this point.

My question is, what's your advice for how I should move forward?

I live near a lot of junkyards and I'm pretty sure I could source a cheap old LSD if I looked hard enough.

But is this worth it? I've heard that most stock old LSD's are pretty much on their last legs anyhow. Though I would be comfortable opening it up and replacing clutch plates if need be.

Also have considered getting the torsen from a Z3, but I hear differing things about it - whether it's worth it, and whether it's a good fit for the E30 as far as going open during wheel lift.

I don't want to spend a ton of money since it's just for street driving and messing around, but I also don't want to waste my time on getting something that's old and broken unless I can fix it myself...

[jlevie]

A used differential could be good, or worse than what you have. It all depends on the mileage the car comes out of. The pricey, but sure to be good solution is to get a limitied slip differential from a salvage yard and have it rebuilt by diffsonline.com.

[monkeyodeath]

That's the reason I was considering a Z3 torsen diff - apparently they don't wear like a clutch-type LSD, not to mention that it would be from a newer car.

[u3b3rg33k]

That's the reason I was considering a Z3 torsen diff - apparently they don't wear like a clutch-type LSD, not to mention that it would be from a newer car.

Torsen. Do it. You'll thank me later. Just keep in mind they don't come with a 3.73.

[monkeyodeath]

So the "going open during wheel lift" thing isn't an issue? It seemed like some of the posts I saw about Torsens indicated that they were more troublesome with RWD cars like the E30.

[u3b3rg33k]

How often do you run into rear wheel lift?

[monkeyodeath]

How often do you run into rear wheel lift?

Honestly, I've been doing a lot more repairing this car than driving, so I don't really know. I was just going off what I had read other places.

Since the Torsen doesn't come in the same ratio as the stock diff, what's a good one to go with that comes close?

[u3b3rg33k]

Well, Mine is a 4.27...

[monkeyodeath]

How bad does that affect gas mileage?

[u3b3rg33k]

I average 21 overall. Keep in mind my driving style is reflected in the joy I take in hearing a MAF'd M20 pass 4k rpm.