On Thu, May 15, 2003 at 08:57:26PM -0400, John F. Kelly Jr. wrote:
> -------------------- Begin Original Message --------------------
> Message text written by "John J. Stimson-III"
> >>"It is possible to get wheelspin without lifting a drive wheel off the
> >>ground.
>
> What you don't say is what kind of tire is installed in the above
> circumstance. And if a wheel is spinning and not driving, then it's kind of
> useless isn't it? Installing an LSD will not give that corner traction; it
> will merely slow down the spin. I'll agree that in that circumstance that's
> not a bad thing. <G> But that corner is still not putting power down.
Hoosiers, Kumhos, street tires...
I agree that if the tire is spinning and not driving, then it is
useless. However, with a torque sensing limited slip differential,
when the inside wheel starts to slip, the LSD applies less torque to
that wheel and applies more torque to the outside wheel. In that way,
you can still put all your power to the ground. With an open diff,
the instant the inside wheel starts spinning the torque to the outside
wheel is reduced to the amount of torque required to keep the inside
wheel spinning -- which isn't much.
> My advice, before spending money on an LSD, fix the lack of power to the
> ground problem.
> This might mean new tires, adjusting the shocks, adjusting the sway bar(s).
The LSD increases the freedom to adjust the car's handling balance
without inducing wheelspin. A car with no LSD needs a stiffer front
swaybar to avoid wheelspin than a car with LSD, and the stiffer front
swaybar may create an undesirable amount of understeer. Without the
LSD, you have to decide which area to give up. With the LSD, you may
not have to.
--
john@idsfa.net John Stimson
http://www.idsfa.net/~john/ HMC Physics '94
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