hernanca

Do tell, Iceman. It sounds like the LSD is best set one way for track but best set up another way for street. My car is strictly for street, but has gobs of power. Is a tighter LSD better for the track?

GregBBRD

Completely depends on the vehicle set-up and the driving style of whoever is driving.
Generally, a tighter limited slip will keep the rear of the car tighter on corner entrance but induce corner exit understeer.
Of course, Porsche produced 928's (along with almost all of their cars of this generation) with generous amounts understeer, which needs to be "controlled" with some chassis/tire/suspension changes, on a track car.
A tighter limited slip will be more beneficial to a driver who consistently uses a late apex technique and is a proficient "unwinder" of the steering wheel. Of course, this is almost always the fastest way around a race track.

Conversely, a driver who consistently is early at the apex of corners and tends to not unwind as soon as possible, will find a tighter limited slip undesirable. (These drivers will also be slower around a race course.)

Porsche developed limited slips with different locking effects under braking than under acceleration. The earliest versions were a disaster, but the lessons learned led to some extremely "sweet" racing limited slips, especially beneficial when combined with modern ABS.

We have been working on this style limited slip, for use in a 928, for several years.

Worth noting, all cars must be set up, when used for high speed track use, to complement the driving style of whoever is driving.

In pure street driving, limited slips are useful when the power output of the car exceeds the ability of one rear tire to contain it. Also useful in wet, muddy, or snow conditions.
Other than that, very few drivers will use the limited slip at (or near) the limits of the vehicle, on the street.

IcemanG17

Doc is right (Shocker)

When I was racing I intentionally setup my racers to be on the edge of loose, with Casper (avatar) being the most loose. I did this by running virtually no toe "in" in front and rear, with enough camber to keep the tires happy....I found the alignment pic the other day, it was 3.5' camber in front with zero toe and 2.5' in rear....I ran Pirelli slicks in 275/645-18 all around. My thinking was I never wanted "terminal" understeer....which my car could do when I ran staggered yokohama slicks same size in rear but a 245?? in front. I always wanted more steering.... Casper weighs about 2850 off track wet with a 200lb driver, 55% on the nose.

The exception was the Krankenwagen lemons racer, which was setup a bit more "tight" since I had several different drivers....and occasionally ran staggered tires....krankenwagon was heavier at 2800 without driver, but had better balance due to the heavier auto being about 52% on the nose and often raced with a full tank of gas