I've tried this spot before but never captured anything compelling enough for me to render. The banking on the curve requires a (shooting) position above it, which is quite a distance away. I have one other shot from this angle that will get posted eventually, just got to make up my mind which one to use.
Not sure if I asked this before. Do you shoot stationary or are you panning with cars as you shoot? I took some shots of the Hot Rod Power Tour, coming into town, on the Business route. I shot at high shutter speed, but didn't move with the cars. Not fuzzy, but definitely motion blur, even if it is very slight.
In this situation I was resting my elbows on the fence for stability. 1/4000 is the fastest shutter speed my D90 can muster, then fire away!
For the shots of cars moving I generally use the pan technique; I do it hand held because tripods are cumbersome and must be constantly adjusted to the line cars take on the track. Depending on how fast the cars are going you can get good results from 1/200 up to 1/500 if you are mostly parallel to the action. It takes practice; you will take a lot of bad pictures, but when everything clicks you look like a pro!
Hey, lookit that! A "Vette Awesome shot, the action here is just palpable as the Corvette gets out of the way of the prototype and loses its line while the Porsche gets away. It looks like that sand and debris got there honestly if the background is any indication.