I'm thinking about installing a LSD in my '81SC. Who are the best manufacturers & suppliers? How about Quaife?

The car is mostly a track car, but I drive it to the track and on occasional weekends.

I know this topic has been covered here from time to time, but I didn't see specifically which diffs are best for the 915 trans.

thanks very much.

 

When you refer to a track car, are you referring to road racing or AutoX?

For AutoX (IMHO) the Quaiffe (or a torsen type diff) is better however for road racing you should get a ZF (clutch) type diff.

 

zf all the way..suggest you contact Steve @ Rennsport - Board Sponsor

 

It's a tough call. I had a quaife in my Carrera, and there were certain things that it did better than the stock LSD. For one thing, it allowed you to put down the power (what little I had) without the understeer that LSDs create. Also, it was transparent when you went from the brakes to the gas, or vice versa.

One thing I wished that it did was to provide lockup on deceleration. I was always locking an inside rear whenever braking was not in a straight line. The new LSDs have a power on/power off lockup ratio, such as a 60/80 which will provide 60% lockup on acceleration, and an 80% lockup on deceleration. An immediate fix for my problem. One other item is that if you ever club race, the quaife is not legal in the stock class.

 

I'll be putting a Guard LSD in this summer when I get the transmission rebuilt. Steve Weiner helped me out a great deal with the decision and he'll be putting together a shorter gear stack for me too.

 

my friends in the business are VERY impressed by the GKN LSD. Alternatively, not as good but more in character is the LSD from the GT3 Cup car, which you can fiddle around with to your heart's content.

R+C

 

Maybe a little off-topic, but I just swapped in a used 89 944turboS LSD gearbox in my car, and MAN is there ever a huge difference around tight corners. No more wheelspin with the a032r's unless I dump the clutch. I can really put down the power no matter what the suspension is doing.

I can't understand why Porsche would build such awsome cars and then put Open Diffs in them!

 

For what it's worth - I just put a quaife in my 944 with a 968 engine, and it vastly improved turn in, and I can now put the power down in 2nd gear corners like the wheels are glued down. Also, these are transparent in street driving - LSD's can chatter like crazy.

Other considerations - Quaifes also come with a lifetime warranty and never need rebuilding. Rebuilding a regular LSD will cost you a mininum of $5-600 in parts alone every 2-3 years depending on how hard you track it.