I've decided to get a limited slip diff for my 540. The car is my daily driver and is autocrossed at least once a month with 2-3 HPDEs per year. I'm trying to decide between the Quaife (torque limiting) and a Salisbury (speed limiting) type LSD. I thought the decision was going to be made for me because the Quaife wasn't available a few months ago, but now seems to be available again.

I've been searching the archives of several forums and see conflicting info. Some say the Quaife works great and others say it won't put down power in hard cornering. Others say the Salisbury chatters and grabs and increases understeer, which I definitely don't want. However, a lot of those expressing opinions seem to be parroting what they've read somewhere else. Do any of you have actual experience with either of these units in the E39 and want to give me some input.

Also, if you would share which vendor you purchased from and the quality of work and service, I would appreciate it.

Many thanks.

I would suggest the quaife unit for the street. Currently it is the best unit out there and what I am offering. I recently found a good source for the units at a fair price. I am working on a custom v8 carrier for the 215k stuff but as of yet, the cost of production is too high and the Quaife fits the bill very well.

A well built salibury unit will make no noise when the proper fluid is used.

might be better off trading up for an M5 as it already has many upgrades you'd do anyways....more power, bigger brakes, LSD diff

I've decided to get a limited slip diff for my 540. The car is my daily driver and is autocrossed at least once a month with 2-3 HPDEs per year. I'm trying to decide between the Quaife (torque limiting) and a Salisbury (speed limiting) type LSD. I thought the decision was going to be made for me because the Quaife wasn't available a few months ago, but now seems to be available again.

I've been searching the archives of several forums and see conflicting info. Some say the Quaife works great and others say it won't put down power in hard cornering. Others say the Salisbury chatters and grabs and increases understeer, which I definitely don't want. However, a lot of those expressing opinions seem to be parroting what they've read somewhere else. Do any of you have actual experience with either of these units in the E39 and want to give me some input.

Also, if you would share which vendor you purchased from and the quality of work and service, I would appreciate it.

Many thanks.

might be better off trading up for an M5 as it already has many upgrades you'd do anyways....more power, bigger brakes, LSD diff

I am watching the M5 market. Prices are definitely coming down (except in the minds of those who are selling them!). The problem is, I've had the 2001 540 since new, it's paid for, only has 47K miles, has a BMW 100K warranty and I know the car. If I was going to get a used M5, I'd have to buy a low mileage car with warranty for $42-$55K and the $20-$30K price difference over my car just isn't worth it (IMO). Plus, my car already has some mods that personalize it. Besides, even if I found a great used M5, I'd still want to mod that. It's a sickness I tell you! :)

540 is fast enough, just need to get rid of the tire stagger so the car will rotate. 245s or 255s all around.

I couldn't say that I would have noticed a LSD on the track, but definatly would help at autoX. What class do you run in?

I owned a '99 sport for 3 years, traded it in to buy a M coupe :)

540 is fast enough, just need to get rid of the tire stagger so the car will rotate. 245s or 255s all around.

I couldn't say that I would have noticed a LSD on the track, but definatly would help at autoX. What class do you run in?

I owned a '99 sport for 3 years, traded it in to buy a M coupe :)

The 540 has more than enough power for autocrossing. I have to be very careful to avoid wheelspin. You can corner sideways with the rear tire smoking if you want, but it's not the fast way around the course. :D I know the car would be much quicker with a LSD.

I have gotten rid of the stagger. Major improvement. Currently running 255/40/17s all around (Falken RT615s). Plan to step up to 275/40/17s when these are shot.

I run GT class with our local club. Essentially the same as FS in the SCCA, with the exception that our stock classes must run street tires, not race rubber. I may change to Street Mod Street Tire (SMST) since, like FS participation at SCCA events, GT cars don't show up much at our autocrosses. :(

Thanks for the posts and PMs related to this issue. I decided to order a salisbury limited slip from Jim Blanton at Performance Gearing. He provided some detailed info and was most helpful in answering questions on the phone.

Ordered a 3:64 with 40% static lockup. Unit should ship by the end of next week. I can't wait to get this installed. I'll definitely post a follow up after I get this installed. :alright

E39 M5 Diff FTW, im sure i could locate one for you if you'd like, I'm just more of an oem performance guy personally. I mean it's on oem part w/lsd what more can you ask for? :D however if you decide that you want to go aftermarket, I'd recommend Quaife-

Don't the quaife's have problems if one of the wheels is off of the ground or close to being off? This would cause problems in an autox situation with the hard transitions and throwing the car around.

Yes.

Salisbury. Talk to Jim Blanton.

Why not go all out and get the assymetric setup on the Salisbury unit? Got mine from Brett Anderson / Koala Motorsport just a couple of weeks back, and I LOVE it. 30% static lockup, and up to 90% under acceleration torque load. AFAIK, all of the major diff suppliers will be able to do it.

3.46 in my Euro 3.2L will run even with a modded E46 M3 now. That and I can launch better now. Doby - no wisecracks about how you beat me in the 2 quick runs we did. You know your launch killed me both times, not the motor ;)

Doby - no wisecracks about how you beat me in the 2 quick runs we did. You know your launch killed me both times, not the motor ;)
We all know it was the driver...