I was wondering how long to leave my car running before I shut it off? I don't have a turbo timer yet but I'm getting one very soon. So in the meantime I have to use my ghetto timer. So how long do I leave it running before I shut it off? Do I have to let it run before I shut it off every time I drive it? Does the fan have to run for a while before I shut it off? Why the hell do I have to let it run before I shut it off anyway? Well If any of you can help me out here I'd appreciate it, thanks.