Why drive smoothly?
 

I was skimming through Mark Ortiz articles again (all of his articles here ) and came across this one by Brian Beckman (physics of racing author) explaining why being smooth with the car is better:

Why be smooth?


If you haven't read any of Ortiz's articles you probably want to!

When I teach driving at road course track events, I preach smooth, smooth, smooth. A less experienced driver usually gets to the track and tries to go too fast, too soon, and they are very jerky and usually pretty slow, even though they are trying really hard (too hard!) I will then get behind the wheel of their car and show them it is possible to run 10% faster with fewer gear changes and other upsetting motions.

But there are exceptions to every rule. When trying to turn one fast qualifying lap, an experienced driver can sometimes go faster by throwing the car through the turns, abusing the tires very badly, but cut a very fast qualifying lap. One cannot drive that way lap after lap because the tires will overheat and the traction will go away very quickly. Mark Donahue's book Unfair Advantage talked about this. Mark's win per Trans Am race entered ratio must show that he knew something.

The unsteady state transients of the tires and shocks, and undampened chassis flex are something that is very hard to be modeled with equations. Mathematical models are getting better every year, but they still are not 100% correct; that is what keeps me employed as an engineer testing motors. When they finally get computer models 100% correct, then I will be out of a job :(