acording to the owners manual, after extended hi speed runs you are supposed to let the turbo cool down befor shuting off the engine. I do with any turbo engine. If you just came buzzing down the street and hit maybe 45oo rpm's and shut off your engine, the turbo is spinning at 25,000 or 30,000 rpm's for a while with no oil flow. the coolant pump helps, but it is still running without oil for more than 5 minutes or so. I always let mine idle for a couple minutes befor I shut down. Minimizing the rpm's that the turbo spins after shut down.