Originally Posted by demontwinz
you guys scare me, I drive slow 5 minutes before my destination and I let the car idle for 30 sec before i turn it off.
I'm at 65 000 miles.
I'm at that same frame of mind. I've owned more turbo cars than not and wasted a few turbos, however it's always been because I've pushed them past their thresholds of efficiency.
Keep this in mind, "coking" of the center section/bearings is a concern of premature wear on turbos. This is the act of oil disintegrating and leaving carbon deposits on moving parts, therefore causing resistance and unbalance. This is caused by extreme heat and rapid temperature loss. You always battle heat issues with a 2 turbo set up.
Ripping on your car before the oil is up to temp will cause a similar unbalancing effect due to the viscosity of the oil not being there to provide full protection.
Change your oil frequently, warm your car up, and pseudo turbo time your travels to prolong turbo life.
As for BMW's failsafe coolant run, I really can't see cycling the coolant after the car shuts off being that super beneficial to saving the turbos. It may help other aspects of the powertrain such as keeping rapid cooling down to a minimum(which is huge when combating warping and stress cracks) but it has very little to do with the major issue with turbo failure. If the oil continued to pump after the car shut off that would be a different story. Watercooled turbos are just designed to keep the center section temps down while running, it's just a heat exchanger. I can't stress enough that oil condition and temp are the winners for this issue.