From digest.v7.n382 Sun Oct 5 20:18:24 1997
From: Satch Carlson <satch_at_alaska.net>
Date: Sun, 05 Oct 1997 07:14:36 -0800
Subject: Oooo! Limited slip!/satch
Poor Cliff James has been listening to the wrong guru:
> If the car is lifted so that both rear wheels can turn
> unrestricted, they will turn in opposite directions if you have LSD. If you
> don't, they will turn in the same direction. This is according to my BMW
> trained certified mechanic at Bimmer Car Care in Bessemer AL. . .
Well, that's what comes of livin' in Alabama (I was about to add the
line, "where a virgin is a nine-year-old who can outrun her brother,"
but good taste prevailed). Next time, Glasshoppah, you are taking
instruction from Gomer, ask him about "differential effect." Speak
slowly; you've entered the world of polysyllability.
Now, then: If a short course in mechanics doesn't work, try common sense
with him. Listen carefully, Gome: The very idea of lim-it-tud slee-yup
b o t h w h e e l s t u r n i n t h e s a m e direction!
Iffen one wheel can turn in the OPPOSITE direction, then in a
low-traction situation, THAT'S WHAT IT WILL DO. Or, rather, it will just
sit there turnin' in NO direction while the other one spins madly in the
mud. What LS does is transfer some of the torque from the spinning wheel
to the stationary one, forcing it to turn, too. . . but NOT in the
opposite direction (although the effect would be spectacular from a
visual aspect. . . talk about yer boot-leg turn!).
By the way, some LS differentials, like the silly-putty Ferguson Formula
units, create this effect, I understand, from spinning plates in goo,
and by varying the holes in the plates, you can affect the torque
ratios. Thus the 325iX has a torque bias of 67% to the rear, 33% to the
front (and the rear is split 50-50). But NONE of this applies until the
car is MOVING; that's why if yer stuck, a 325 will not crawl out of a
hole like something with locked diffies fore and aft. In a fast, wet
corner, however, the effect can be a m a z i n g ! !
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