I sure hope you mean actual, at the track racing. Since you're asking the question, the answer is yes, keep it on. It will help save you when you outdrive your skill and/or vehicle. If it's drag racing, then turn it off, let the AWD dig do the work. Not to sound like too much of an ass, but a good, trained driver doesn't need traction control (especially with AWD) and would know to turn the switch off as soon as they entere into pit lane from the garage. Since you're asking, I'm assuming you're unsure of your own skill, in that case, the TCS may not be such a bad idea.
If you're just flooring at the lights on the street, then don't do it at all, it's just stupid and proves only one thing, who the bigger idiot is.