Zakly . . If you don't have one, get one . . If you're a serious drag racer you have one in your trailer and your crew chief/spotter has one in his hip pocket . . It's part of the data acquisition department. Track Temp, Tire Temp, Engine and Converter Temp when the car comes back from a round, etc . . And as Zipper said, use it to check your cylinders firing . . as well as EGT if the headers are exposed . .