Brent, I know you have something here. I have heard road race drivers will stay a "gear-up" in rain to help with traction. I have always thought that if I put a taller first gear in I would gain time and traction; However, this is not 'tunable'. I would suffer when track conditions are real good. John ---------- > From: Brent Brown > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: Ignition timing, 2nd iteration.... > Date: Tuesday, May 02, 2000 6:29 PM > > > > 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 > > > > Just wondering - is this a known formula / observed rule in drag > racing or can it be applied more generally? A little off topic now but > I have often pondered this and tried to figure out my own > explanations, thinking how a micro based traction control system > might tackle the problem of fast starts for ant kind of race car. > > Though a slightly different situation, my experience is with two > stroke 250cc moto-x bikes that develop 45-50hp. The formula for a > fast start on soft dirt / grass surface is a high gear, say 3rd or 4th, > and full throttle. As land speed increases the revs drop back > slightly to that magical max engine torque / max traction magic > value and for a while acceleration greatly exceeds that possible > with zero slippage. (My brother and I have verified this by extensive > side by side standing start tests on a grass air strip!) My guess is > best acceleration occurs somewhere around 20%-50% slippage > shortly after the start for as long the engine torque can keep up this > condition. > > Similar technique works when stuck in mud at the bottom of a > slippery gully. Put the bike in first gear and it wont budge no matter > what the revs, do the 3rd/4th gear full noise trick and it's amazing > how traction develops. > > Probably quite different to the drag car situation but I'm still > interested in the laws at work here. Oh yeah, to get back on topic > you could super glue DIP packaged PIC16F84's, with legs pointing > up, to the drag track for more traction. You'll need around 35000 of > them for two rows 0.25 mile long, but the good part is you don't > need to program them. > > Brent Brown > Electronic Design Solutions > 16 English Street > Hamilton, New Zealand > Ph/fax: +64 7 849 0069 > Mobile: 025 334 069 > eMail: brent.brown@clear.net.nz