new winter project on the list calls for a rebuild of the trans in my 1981 911SC track car. i'd like to add an LSD but would like recommendations on brand, etc. please remember i am on a budget. slightly used is ok. also are there different types of LSD that will fit my car and is one better than another for track use. I should mention the other winter project is to replace the 3.0 with a 3.6 (964 or 993) but don't expect bhp to get above 275 or so. all help is appreciated. thanks

 

Hi,

For track use, the only type of LSD to use is a clutch-pack typ of unit. Unlike Torque-Sensing differentials, these keep the rear wheels locked together under trailing throttle to stabilize the car under heavy braking and eliminate that side-to-side wiggle.

You can use either a factory ZF unit, the excellent Guard LSD (which is adjustable) or the OS Giken ones. Costs vary and each one has its advantages,......

If you install a 3.6, I'd STRONGLY recommend installing the Wevo one-piece bearing retaining plate and a billet side cover for durability.

 

Thanks Steve - i've seen talk about a fine spleen vs coarse spleen. whats the difference and why doi care?

 

Early 915's, '72-'77, used coarse-splined stub axles; later 915's like yours used fine-splined ones.

Its critically important to know before ordering the LSD,...