andy howard <music@soon.com> wrote:

> > I read that pro street stock racers use timing computers to help
> > with traction, and guard their curves with their life.
>
> Do you need to tweak the timing for that?

    Andy:

    He doesn't have many other choices; traction-control is banned
    in his form of motorsport, but ignition timing curves, gearing,
    and rev limits are "free" (i.e., they can be set to whatever he
    likes) in most classes.

> I'm just thinking out loud here. Since you have maximum traction
> when there's no wheelspin, maybe you could devise a system that
> compared the rotation of the front and rear wheels and slightly
> backed off the throttle if it detected any slipping, checked again
> and backed off if... etc.
>
> If it detected no slipping and your foot still hard down on the
> pedal it could nudge the throttle up again until wheelspin started
> again.

    That's the way the traction-control system on my car (and most
    others) works, and it's fine for keeping the wheels from
    spinning on ice or other slippery surfaces.  It sucks, though,
    for drag racing... For many reasons, some of which are:

        1.  Wheelspin on launch is NECESSARY for the fastest times

        2.  The deformation of the rear tires under heavy
        acceleration changes their circumference (in the wrong
        direction), so the traction-control system will incorrectly
        see slippage when there is none

        3.  Maximum traction isn't developed with no wheelspin,
        anyway; the most acceleration is developed when the tires
        are slightly slipping

    -Andy


=== Andrew Warren - fastfwd@ix.netcom.com
=== Fast Forward Engineering - San Diego, California
=== http://www.geocities.com/SiliconValley/2499