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Re: More Traction Control...

To: "DrMayf" <drmayf@teknett.com>
Subject: Re: More Traction Control...
From: "Ed Van Scoy" <edvs@uswest.net>
Date: Thu, 19 Apr 2001 20:15:48 -0700
Which brings up a question.............I assume traction control is allowed in 
the
production classes...??? Corvette has come equipped with ASR (accelleration slip
regulation) since 1991. When it detects wheel spin, it works by closing the
throttle and managing the spark system, and applying the rear brakes. The
accelerator pedal is forced back up, & try as you will, you cannot "power out" 
of
a skid with the ASR on (it is switchable). So, if a person were to put the '91
system on an '84 Vette, it would be legal?
Ed (not trying to throw gas on the fire, and FWIW, when drag racing &
auto-crossing etc., I always turn it off because the DRIVER can do a better job 
-
that's why GM put an on/off switch in the system)

DrMayf wrote:

> I got up with multiple senior moments today and am having a bit of trouble
> with traction control. I guess one or more of my problems deals with absolute
> statements of unenforceable and undetectable. I also gott a sk what is
> everyones definition of traction control? Before any rational discussions can
> be had, the parameters of the discussion need to be known to all. Now, to me,
> there are several forms of traction control. The first in my mind is when the
> vehicle is at full boogie and hits a soft or wet spot and the engine rpm goes
> up dramatically and then down again when better traction on harde or dryer
> salt is under the drive wheels. Then there is the case when only one drive
> wheel gets loose which to me is a rally bad situation because this causes a
> force vector off centerline pushing the vehicle out of line. For the first
> condition where there is even traction but loose, then traction control may be
> had by lowering the engine speed but I really don't think it could be done
> efficiently. This would require that the motor power be reduced then regained
> very quickly to stay on the run. This could be done by looking at the
> instantaneous rate of rpm rise and cutting back on the throttle just as
> quickly. Ditto for reengagement. The second problem, of one wheel slipping, is
> a little bit more complicated in that the rear diff cannot be locked or use a
> spool, it must be free to allow the high rotation speeed of one wheel vs the
> other. Then the wheel with the best traction has to be decoupled enough to
> assure that both wheels are now equal. This is, I belive, a basic premise in
> todays traction control, although I could be wrong. In this case a wheel speed
> sensor is required at each driven wheel for the on board computer to compare.
> Highest wheel speed gets the brakes applied. So what is wrong here...well
> applying brakes means slower speeds, not faster. Traction control of the first
> kind would work wonders on the drag strip because you would only apply the
> amount of horse power that the track could take and this would result in
> really low ET's. But not necessarily higher top speeds. Quick is not
> necessarily fast. This kind of traction control would require some
> differential wheel inputs such as wheel sensor and a separate undriven wheel
> sensor to compare to determine wheel slippage. A pretty simple computer could
> do this, say a small stand alone unit programmed in basic or similar. It would
> output throttle position to control horsepower if the right effector was used.
> The second case might be a little tougher because of the electronics in the
> car itself. Most of the new cars have pretty determined computers and back
> engineering is not available. Let anlone any way to reprogram them. But then
> who wants to apply the brakes when top speed is where we are trying to go.
> Like most of us, I wont be trying it in any fashion as described, I'll just
> let the seat of my pants tell me what's going on...
>
> was this a senior moment also? a brain fart? prolly....I'll wake up in a
> minute or so and ....
>
> mayf

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