In Championship mode when you're in Germany you get 3 boosters(NOS) If u get into an unfortunate accident, you can use one of these by pressing "C down" This will make your car go to atleast 197 mph(depends on power level).
My only piece of advice to you is don't use it on turns trust me it will mess you up "HARD"!
NOTE: If you decrease the number of laps the NOS will decrease as well. If you increase the NOS the maximum amount of NOS will STAY THE SAME!(3 boosters)