[mosc]

people say that you should leave turbo cars on but basically if you haven't been using the turbo in the past few seconds, it's really not something to worry about. If I was doing drag pulls on it, I'd give it maybe 60 seconds before turning it off. If I was driving around the neighborhood too fast before pulling in, maybe 30 seconds. Most of the time I do zero seconds because it's been probably a minute since I used any boost before coming to a stop anyway.

People sell turbo timers which will keep your car running for x seconds after you remove the key and then turn off automatically but they're really not needed. The concern is the turbo cooling off which it does quite rapidly, especially because it's small. It's not instantanious and I suppose you could damage it if you turned off your car after each drag pull (not that all of us even DO that) but really from everyday driving, it should not be a concern at all. That's why it's not in your manual.