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Turbos - midlifecrisis
Do todays modern Turbochargers need time to cool after use. I know drive a Passat 1.8T and often wonder whether I should let it idle for a minute or so after a run. I know it was advisable a few years back, but is it still necessary today.
Turbos - Simon Templar

The 2 minute cooling rule has not changed.Avoids cooking turbo bearings-unless as one poster maintains- the turbo is never used!
Simon T.
Turbos - Tomo
"Re: Turbo Question Please. - j.cronin Thu 21 Mar 02 19:22

The exhaust side of a turbo-the cast iron bit-will be well red hot when running at max power-max speed.The main time this should cause problems is entering service areas on german autobahns where the pumps are the first items you come to;most french autoroutes have a sufficiently tortuous entrance that the turbo will have cooled-same for going home-a thirty limit will have allowed it to cool.Some very high performance engines have a water-cooled turbo to overcome these problems."

Seems sensible to me. If you have a garage, keep the key otherwise than on the car key ring - with house keys? - so you leave the engine running while opening the door, then trundle in and switch off. Away from home, there's often enough time spent backing and filling to get parked; otherwise, give it half a minute to be on the safe side.

(What do the Germans do arriving at a petrol pump, where they preumably switch off, with a red hot turbo?)

Tomo


Turbos - jc
All Ford vehicles fitted with a turbo(petrol and diesel) have an oil-cooler fitted and before someone says they can't see it,it's a Modine cooler(oil-water) usually fitted between the filter and the block which uses the return coolant in the heater circuit to cool the oil.
Turbos - Cyd
Yes.

My Rover (petrol) turbo (which has water cooled turbo bearings) recommends up to 10 minutes after a fast run. It also puts the fan on for 10 mins if you don't (but this offers little long term protection). Just a couple of miles of hard driving is enough to make this necessary as the turbo gets very hot very quickly.
Just as a test recently I thrashed her through the lanes, then pulled up on the drive and turned off. Within 20 seconds I could hear the water boiling in the turbo. The fan came on about 15 seconds after switch off. I switched her back on and ran the motor for a further five minutes at idle. No boiling & no fan.
Now, if I've been driving quickly I allow the car to idle, wait for the fan to cut in and then turn off after the fan goes off. This is usually about five mins. Seems to work.

Conversely, when you start up in the morning you should let the engine idle for 10 seconds before driving off to allow the oil to get circulating properly (this advice is also in my Rover handbook). I also drive gently for the first few miles to allow the turbo (and oil) to warm up.

Fortunately for me, the previous owner of my car (a friend) was also well aware of this advice. The car has done 116k now and is going very strong. Failing to follow the above proceedures can result in a blown turbo in very short order - ever wonder why there are so many turbo rebuilders advertising in the front of your local Autotrader???
Turbos - Cyd
Oh, don't blip the throttle just before turning off. Allow the engine and turbo time to settle at idle. If you blip the throttle then turn off, the oil supply to the turbo bearings is cut because the engine is no longer turning, but the turbo could still be doing 100,000rpm or more!!
Turbos - jc
To have to leave your car idling for ten minutes does not seem to be in the real world-some journies would be quicker by push-bike.It sounds that whoever did the original calibration was trying to save money by running a too-small turbo too hard.
Turbos - Cyd
Hardly! It only runs 12psi and produces 200 bhp from 2 litres. It can be chipped to as much as 280bhp! Plenty of spare there.

All turbos get very hot when in hard use - remember the principle at work here is to remove heat energy from the exhaust gases and turn it into compressed air at the inlet. Exhaust temperatures can approach 1000C.

In the days befor water cooled turbos one could drive a Saab 99 turbo hard down the motorway and lift the bonnet to see the turbo casing glowing red!
Turbos - Cooperman
I have the same engine in my Audi and asked the forum for some clarification on this subject back in October last year. The thread can be found by doing a search on "Audi 1.8T 20V engine"