> -----Original Message----- > From: Andrew Warren [SMTP:fastfwd@IX.NETCOM.COM] > Sent: Wednesday, 3 May 2000 9:05 > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: Ignition timing, 2nd iteration.... > > andy howard 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 > Correct, it is around 6 to 10% slippage Dennis > === Andrew Warren - fastfwd@ix.netcom.com > === Fast Forward Engineering - San Diego, California > === http://www.geocities.com/SiliconValley/2499