So I know that you are supposed to cool down the car before shutting if off after hard use but can anyone give a good explanation as to why and details about how to do this. Right now I just drive at below 3k prms for 2 or 3 mins before shutting it down. Is that enough?

 

There was a thread a few months back about this and Stephen of Imagine Auto who's a board sponsor and extremely knowledgable about these motors basically said driving slowly will not do it. He suggested letting the car idle for 2 to 3 minutes before shutdown. You will eventually cook the turbo bearing if it's not cooled down by oil flowing through it after it has stopped spinning which will only happen at idle. It's a bit of a pain but I've gotten used to doing it.

 

From what I have learned on this and other forums (from people way smarter than me...like Kevin and Stephen) the car should idle for 2 minutes after you stop driving. The reason is that when you shut the car down, you stop the flow of oil which is what cools the turbos (like Bruce says). It is not sufficient to just drive mellow for the last couple of minutes (although this may help).

 

I have to agree with the above also, everyone in the know with these cars lets them idle for 2 minutes to let the turbos cool by the oil continuing to flow, shut down stops this process imediately the oil left around the bearings gets so hot it "cokes" and byebye turbo, or hello upgrade!

 

surely it would have the same effect not using boost for the last couple of miles-oil will flow through the turbos and cool them down.

 

I thought the reason for idling after hard run is to let the exhaust oil spin off of turbine fins. Keeping the oil flowing makes sense too though. Anyone use a turbo timer?

 

Time for a turbo timer. Just make sure it works with your factory alarm.

I had a turbo timed Rx7 Turbo II get stolen and stripped because the turbo timer kept the factroy alarm from being activated. I got it back minus engine, tranny, seats, and all sheetmetal from the doors forward. It was a great downhill racer after that!

 

You dont need to wait 2 minutes after every drive....

the 2 minute rule applies after you've really been on the boost..... so for most guys here...I guess that would be after every drive....

Seriously..if you just take a quick drive to the local store, etc. and dont get on the boost...there's no need for turbo cool down...

 

I agree with BCS996TT, but I would also think that if you have been hard into the boost for a while and then drive normally for a quarter hour or so the oil in the tubo cicuit will have reached its cool stage (is that not what the oil coolers are for?) temps and the turbos will be about as cool as they are gooing to get. Idling a car does not really cool it down much (and the oil and water in the cooling system), in fact older cars would get too hot if not moving (not just air cooled cars) as the water cooling system had to rely on the clutched fan to move the air through the radiator with no wind help. The manuels of most cars usually say someting about idling a car too long and overheating.

I have a tubo engined plane too, it needs a 4 minute cool down, but that includes the off throttle landing and taxiing process. There are always those purests (particularly in aviation) that demand a static cool down period.

 

About the old cars, if my 924 or 944 idle for 5 minutes, they will begin to overheat. It is a real treat in bumper to bumper traffic.