Turbo cool down time...
Twenty seconds or so is fine for around town cool down if only side streets are used. If cooling down from a high speed drive, 65+, with weather hot, allow for at least a minute for a proper cool down. If it's really hot and you have been really sticking your foot in it, you may want to add a minute or two to the time. If you have to drive for a few (2 to 5 miles) to get to your destination from the free way, than an excessive cool down is not needed. Our turbos cool down best when we are still driving, as long as it is slow and easy, not using the turbo much at all. Using synthetic oil will help decrease the temps. and it will definatly help when a complete cool down is not possible, or if you forget....to decrease the formation of any sludge, ect. Good Luck, and treat your turbo with care when cooling it down. It will last many miles if you follow these guidelines. JK