They don't use it for the race, only for qualifying at places like Daytona. For everyone's education the way to hide it is having a battery half filled with nitrous and run it into the engine block through the battery cable into a nozzle under the intake. The Dodge pro stock teams did this when they kicked ass in NHRA. Rumor had it that when Jeff and Ray were dominating they used this tactic. Ever wonder why that team was split up? Was easier to do that and give Ray what he wanted (his own team) then for the ugly truth to come out! If it was found out that he was cheating and NASCAR allowed it what do you think would happen????