[Norrie]

Does anyone let their car idle for a couple of minutes when they get to where they're going to cool the turbo down? What's a good rule of thumb for this?

 

[6thElementEngineering]

Does anyone let their car idle for a couple of minutes when they get to where they're going to cool the turbo down? What's a good rule of thumb for this?

Though I haven't seen it in person to confirm (I have only see diagrams) the turbocharger is cooled by engine coolant.
If it were me, I would only be doing what you are doing after arriving to my destination following hard acceleration and lots of boost.

If you are just driving around normal and need to turn the car off I wouldn't worry about wasting your time.

 

[Redturbo]

I do it only when i've done a hard pull. The turbo shouldn't need to cool down unless you've been in hard acceleration like mentioned above. They make a turbo time (not for our cars yet) but for others that have been around for a while. One of my friends with an SRT-4 had a turbo timer on his car. It would stay on for 30 seconds (you can change the time) after he got out of the car, then cut off giving the turbo enough time to cool down. But it would do that even if he drove normally. It doesn't hurt to sit for a second but it isn't necessary unless you've just done some hard pulls.

 

[Markus]

Yup, had a turbo timer (GREDDY) on my Impreza. I could have a couple of presets, usually had it set to 1 minute. If I'd been on a hard run I'd get out, lock the car and let it sit there while the timer counted down. The normal method was, for the last 10 mins of the drive, to just drive at a normal speed, which allowed things to cool down on their own.
It was quite normal for a bunch of us to turn up at a meet and stand around chatting while the cars cooled down for a couple of minutes. We'd also warm the cars up before going too. I know, I know, a bit weird, but hey, what do you expect

There's also the fact that, I seriously doubt, unless you live in the middle of nowhere, that you're going to be driving at a high rate of knots right up to your doorstep, so it should not be a problem.

 

[honhon]

I usually drive down my 2 streets in the highest gear I can to keep the RPMs as low as possible... its about a 1/2 mile so I think that's cooled enough plus I let it idle for another 10 to 15 seconds in the garage...