>>3111214>maybe try shooting on a faster straightaway with a longer shutter speed and tracking the car with your lens so that the background gets a little blurry but the car stays mostly sharpPretty much this. You basically never want the rims of the car frozen. The more motion blur you can get in, the better. Drop your iso, tighten down that aperture, and try to shoot at slower than 1/40 (varies based on speed of the cars, distance, and your position on the track). The slower a shutter speed you can shoot, the more blur you can get on the rims and in the background. Monopods are super helpful for panning shots.
Personally, I prefer shooting corners over straightaways. The panning motion is a little different, but the results are usually a lot more interesting.
Oh, and don't feel bad if you start off getting really crappy cull/keeper rates like 20:1. It takes practice to get this stuff down.
imgur /a/am3WQ