"Peter Sterne" <pete@greenwich.com> schreibt:
>I've read about E30 BMW's having a high probability
of rolling when
>autocrossed, and was wondering if this included the
E30 M3? (No flames
>please, I am _NOT_ saying that E30 BMWs will roll
when autocrossed, I'm
>saying I read about it here on team.net)
I haven't heard of one, but I expect it isn't as
likely. The M3 rear suspension geometry was rather
significantly revised from the 'cooking' E30.
FWIW the likely cause of the E30's propensity to roll
is the semi-trailing-arm layout of the rear
suspension. The roll center of such a design is very
high compared to a strut or double A-arm design, which
means that cornering forces tend to lift the body,
which raises the roll center, which lifts the body
more, and so on until the center of gravity moves
outside the tire contact patch and the car rolls.
Same thing that happened with swing-axle Corvairs and
Spitfires, only not quite as sudden. The same
suspension, and same problem, is shared by 318Ti's and
Z3's (yep, one of those even rolled at Mineral Wells a
couple years back).
Fiddling with pickup points as on the M3 can help, but
the better solution is to ditch the whole thing in
favor of a multilink as on the E36. Or get a Miata...
:)
Craig B.
Bid and sell for free at http://auctions.yahoo.com
|