I'd say if someone has a turbo charged car, read the manual. Last I looked, the Audi A4 with the 1.8L Turbo, the manual said that it needed about 2 minutes to cool down. I know with an 18-wheeler from my understanding, they recommend about 5-15 minutes. I know neither vehicle have anything to do with our vehicles, but I'd say with that being said, I'd recommend the Turbo Timer, for longevity of the turbo and car. But I may be wrong. But just my opinion on it. -Gary