You have to type the cheats in slowly or the game won't register them and they won't work.

All Tracks and Cars (U.S. version):
At main menu (where you can choose track or cars), enter KEVWOZEAR. You will hear a clang to verify that it worked, though it may take a few tries.

Hit L in game for a coordinate and a mile-counter display.

Holding down Z at the start line before the count down ends to pull away early. But you lose 1000 credits which you can make up for by killing the marshal. (the "Z" key can also be used for a wheel spin)...

Thanks to Revolution readers Zachary D., Jayme Green, Michel, Spazz, Katt, and Craig!