Me too. It takes me 2 minutes to get down my driveway and into the garage. I figure I'm good. Any other time... 2 minutes or so depending on how I drove it the last few minutes.

 

I idle my 930 for several minutes prior to shut-down, but the TT, I come off the throttle for the last couple miles before I get home, let it idle for about 30 seconds, then shut down. Once in a while, the engine fan will come on after it's been sitting for a while and run for several minutes before shutting down. I would think that if the engine were truly overheated, the fans would be running when I initially shut down. There's a big difference between the air and water cooled animals.

 

From the owner's manual:

"Do not stop the engine immediately after hard or extended driving. Keep engine running at increased idle for about two minutes to prevent excessive heat build-up before turning off the engine."

While it's probably not a bad idea to do this all the time, it's probably not required for short, less spirited drives.

 

I am going by Kevin at UMW, who happens to build and rebuild a LOT of turbochargers. No, you may not need to do it. But, if a guy who repairs turbochargers and builds them as his main business suggests I do it (causing him to lose business in theory....), I just do it.

I like overkill on an engine I cannot afford to trivially replace.

Simple as that. The 50$ in wasted fuel over the 10 years I do it is no big deal to me.

My source is now out there in the open. No tuner wars please. UMW (Kevin) makes great turbos. Porsche Motorsport has used his services..... Everything he has predicted about my car and my needs has come to be true....let's just say that. He told me that he measured it and 2 minutes was the optimal time. I did not cross examine him as to how he did it..this was two years or so ago. I just trusted him at his word.

Just saying what I do and why. To each their own. It is likely the optimal way to do it in terms of turbo life span protection. Not sure it is best for every busy lifestyle. He did say idle is very different than driving slowly/easy off boost to the engine management and oil flow/temp issues, and not to count that time. It was not a bad idea, but did not count to the 2 minutes.

Jeff

 

The 2 minutes at idle is not all about "cooling" the turbochargers during the idle time period...it's also about allowing the turbochargers spin down closer to their idle RPM prior to being deprived of oil at shut down. For example, when driving easily at say 2500-3000 RPM under no boost (0.0 bar), the turbos are spinning way above their idle RPM. If a driver motors along for a few minutes under no boost and immediately shuts down the engine when he reaches his destination, the turbos are still out there spinning away above their idle RPM when the oil supply is shut off. In this case the heat generated while the turbos spin down to zero RPM can cause coking. The higher the "motor along" RPM (even under no boost), the higher the turbocharger RPM, and the longer it takes for them to spin down.

So I personally consider the 2 minute idle prior to shut down a turbo "spin down" time more than a turbo "cool down" time.

 

Always do it... at least 1 minute but most of the time 2.... cheap insurance.

 

Darn, so tell me again why the conventional turbo timers won't work? It seems that as the cars been out for quite some time an alarm work around would have been found by now?