having driven a mustang with essentially an open diff, i can saw for sure it
is NO FUN to drive a powerful car with no LSD. you cant get any weight
transfer to the back of car, so you have less than 1/2 the traction. i
remember coming out of corners that i can hammer in my car, and in the
open-diff mustang with 125 less HP, 1/4 throttle would cause wheelspin.
1/4 throttle is, well, less power to the ground than a miata! you cant jump
on the gas to get both wheels spinning and drive the rear of the car with
the pedal and the front of the car with the steering wheel, which is the
only way to cowboy those nose-heavy iron juggernauts around the course.
james
----- Original Message -----
From: "Tibbals, Paul" <PHT1@pge.com>
To: "John F. Kelly Jr." <76067.1750@compuserve.com>; "Autox (E-mail)"
<ba-autox@autox.team.net>
Sent: Thursday, May 15, 2003 1:31 PM
Subject: RE: Atwater questions
> John said,
>
> -----Original Message-----
> From: John F. Kelly Jr. [mailto:76067.1750@compuserve.com]
> -------------------- Begin Original Message --------------------
> Message text written by "Tibbals, Paul"
>
> " Open diffs take away much of
> the advantage of powerful cars. "
>
> -------------------- End Original Message --------------------
>
> Are you REALLY, REALLY sure about this?
> How do you know this?
>
> If you were sitting in a room somewhere in middle America writing a rule,
> would your statement play heavily on your rule-writing decision?
>
> Or maybe somebody you greatly respect stated the above. What would happen
> if you found out your thoughts were in error?
>
> --John Kelly
>
> Paul replies:
> Just to be clear, that text you quoted was not from me! It was from
Peter, replying to me.
>
> Whether I respect them or not ;) the Board members who wrote the Solo2
rules apparently agree with that statement, as one item that seems to be
prohibited until cars are SUBSTANTIALLY altered (STX, Street Prepared) is a
LSD.
>
> IMO, the open diff definitely limits MY car's performance vs. having an
LSD. I feel that in general they are not offered by the manufacturers from
more of a safety (read: limitation of liability) concern! Take your average
Neanderthal untrained driver (non-SCCA member), who has a wallet full enough
to drop for a pony car with monster V8. He/she nails the gas in the middle
of a corner the inside tire spins and the car won't be that upset. With a
limiting/locking differential, however, both rear tires lose grip and the
car goes off bass-ackwards. Of course it's a cost item as well. To my
great dismay the Quaife for my model is a $1300 item =<8-0 and that's not
including installation. If I had sprung for one, then subsequently gotten
involved in autocross however, I'd be in STX or ESP. While I do not have
personal seat time in the same car with an LSD, several people who I know
have that exact setup with same or much higher power. These drivers have
stated that the o!
> verall corner performance is improved because they can accelerate earlier
and harder. And that the difference is greater in lower gears where
wheelspin is easier to induce, which is exactly the range that I use during
autocross.
>
> So is it your contention that I'm inferring from your tone that an open
diff slows down a low-powered car as much as a high-powered car? Or do you
think that it doesn't slow down a car much?
>
> PaulT
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