I occassionally wash the car before a race, but never after - why?
I read somewhere exactly what Majarvis wrote, that it very slightly helps the aerodynamics. If you´ve got lumps of dirt stuck to the paintwork instead of a smooth shiny waxed surface, it must produce some drag. So maybe it is only on the Test Course with a really really fast car with lots of bodywork that you´ll notice the difference. Someone also said once before that you don´t see a difference in the race, but the car is more shiny in a replay.
Another challenge Famine - care to join me on this one?
* Test Course - Like the Wind (can start but don´t finish - obviously)
* Choose your car - preferably a very fast one with lots of bodywork - and unwashed.
* Let us know your car and top speeds without a wash and top speeds Immediately after only a wash. Perhaps if you oil change before each attempt - what say you?