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RE: Traction Control

To: "'land-speed@autox.team.net'" <land-speed@autox.team.net>
Subject: RE: Traction Control
From: "Waldron, James" <James.Waldron@CWUSA.COM>
Date: Wed, 26 Jun 2002 11:10:29 -0400
Seems to me one of the best ways to do this would be to
sense road movement (how fast and what direction I am
passing over the surface - sonic or RF doppler radar? ),
tire speed (to match the tire speed to the surface speed +/-
a little slippage factor) and G load.  Keeping the tire
speed pretty well matched to the asphalt/dirt/salt would
seem to be the best way to maximize the traction.  Watch the
G load in a curve for its maximum value.

>From a safety standpoint, such an arrangement should help
prevent straight line (not in a turn) spins.  (Though
occasionally I've gotten the 360 degree tour when the tire
speeds were well matched to the surface - suspect loose
material (sand) or surface roughness in harmony with the
suspension.)

Then again, if you're going rickety split and you jerk the
steering to one side, all the rev reduction in the world
probably won't help.  But if you were negotiating a constant
curve it would be very seductive to just floor it and let
the computer walk you up to the knife edge.
Makes the accelerometer rev limiter combination sound
plausible.  In the turn, keep allowing a little more and a
little more rev to create a little more and a little more G
until you either start to lose G (sliding starts) or the
pucker factor lightens your foot.

Scary part is that if you are right on the edge, one blip
and it's gone.  Now if you are 'driving' at that point, you
may be on top of it enough to save it.  If you are just a
'passenger', you may not be able to get it together fast
enough.  My experience with racing tires is that they stick
great up to a point, and then break away fast.  Once
traction is lost, I have found it 'very' difficult to re-
match a racing tire to the surface (regain traction).
Street tires seem to be much more forgiving and much easier
to get 're-stuck'.

Comments or other experiences?

Jim.

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