Turbo charged car is not advisable to immediately put off the engine when it came from travel?

Question

Is it true that when you are driving a turbo charged car and you are going to put off the engine it is not advisable to switch off right away the engine. You wait for a minutes to switch off the engine. Why?

Answer 1

It's true that Top Contributors often don't know shiit. They just ask themselves questions under another ID and pick themselves as best answer over and over until they make TC. Turbochargers are driven by the car's extremely hot exhaust, and they spin at many more thousands of revolutions per minute than the engine, especially when the car is being driven at highway speed. The faster the engine is running, the faster the turbo is spinning, and the hotter it gets. Therefore, they operate at extremely high temperature, and under much worse conditions than the engine. They are often lubricated with engine oil, which is cooled by the car's cooling system, and possibly by an extra oil cooler. When you shut off an engine, all the heat that was being removed by the cooling system has nowhere to go, so it all gets radiated under the hood, heat-soaking everything under there. Because the turbocharger bearings operate so hot and so fast, there is a tremendous amount of heat that is normally drawn away by the flow of the oil. This heat is no longer being carried away if the engine is not running, so the oil that is still in the turbo's bearings can cook, and there have been issues with that oil even crystallizing, which means that it is no longer able to lubricate the turbo's bearings, and it could block the oil passages, destroying the turbo. It used to be recommended that turbocharged cars be allowed to idle for a minute or two in order to let the turbo cool down before shutting off the engine. It's not so much any more because of advances in engine oil and turbo bearing design, but it still isn't a bad idea. Frankly, it's not a bad idea even if your car isn't turbocharged, especially in hot weather. Letting some of that heat dissipate at idle after a fast highway trip, especially with the air conditioner blasting, will help keep your car from boiling over when you shut down.

Answer 2

This idea came from back when turbos were quite primitive.
Back then they old had oil cooled bearings.
During hard driving the turbine blades get extremely hot , this heat then soaks into the shaft.
If you were to switch off the engine there would be no cool oil to take the heat away from the bearing assembly , which can lead to damage.

So then they invented turbo timers.
A timer that allowed you to keep the engine running after you take the key out lock the car and walk away.

Since then there has come water cooled turbo's.
These keep the bearing assembly cooler under almost any condition.

While it is still recommended to let the car idle down for a few minutes after a hard run it is a lot less of a time compared to the older generation of turbos.

For the average low boost turbo car , an idle down time or as turbo timer probably is not required.

Answer 3

think of it like this: your engine is spinng at lets say 4000 RPM while driving, your turbo sping ten times faster than your engine so the turbo is spinning at 40,000 RPM if you shut off your car you loose oil preassure so there is no oil flowing through the turbo but it is still spinng very fast, no lube+lots of heat and friction=Blown turbo bearings. Leaving the car running for a minute or two at idol will slow the turbo down so its not spinng anymore when you shut the car off. Buy a turbo timer so you dont need to sit in the car while it is running, it will shut the car off by its self after a minute or two:)

Answer 4

The lube oil @ the turbo takes a lot of heat when under load, or driving hard. Running the car lightly won't build up too much heat. If a car is shut down when hot, the bearing(s) can cook the oil and break it down into nasty stuff.

Answer 5

Your Chinglish is very good. Haha!

Unless you are talking about drag racing there is no waiting time to shut off the car unless you are flying down the Interstate at 120 MPH and jam your car into the rest area doing 120 MPH.

The housing on the turbo will turn orange at higher speeds and it will take a minute to cool down. I've seen them get hot enough to make a water hose pop that was 12 inches away. No heat shielding.

Normal driving does not dictate a cooling off period before you shut down the motor.

Good Luck!

Answer 6

yes..

This is because.... turbo charger will be spinning at very high speed - during normal course of usage....

Hence you need to idle engine for approx a minute... and allow it so slow down before cutting off engine....

As soon as you cut off engine.... oil supply to turbo charger bearing is stopped.... this may damage the bearing - if turbo charger is spinning at very high speeds...