Quote:
Originally Posted by Ladogaboy
I would fly my current car out there. Why would I have it if I didn't want it?
This is a myth. It used to be that turbos were cooled only by oil flow, so when the engine was shut off, the turbo would stop receiving coolant. That is why so many aftermarket companies sold turbotimers. The timer would keep the car running at low load to cycle oil and cool the turbo before engine shutdown.
As I understand it, current turbos are cooled by both the engine oil and the regular coolant system, so they will continue to cool even after engine shutdown. As one person so aptly put it, "These cars come from factory with this turbo.The manufacturers know that morons will not continue to let their cars idle prior to shutdown, even if instructed to do so. So, if these cars actually required a turbotimer, wouldn't they come with one from the factory?"
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My current car is one of those rust nightmares that I spoke of. It can stay back home for when I return for vacations
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Interesting! This is the first that I've heard that turbos on newer vehicles are cooled by engine coolant as well as engine oil, but it does not change my opinion of P&G with the turbo. When you turn the engine off, the engine coolant stops, and the engine oil stops. Therefore there is still no coolant from either source when you shut it down. Normal drivers will calmly reach their destination and shut of their turbo car, 2-4 times per day. Nothing wrong with that. Myself on the other hand will push the car at pretty much wide open throttle (note the BSFC maps for TDi Engines) for 3 seconds, shut the engine off, coast for 10-20, then restart and repeat. I might do this 200 times during a commute. This would cook the oil into the bearing and cause "coking". The coking results in a blockage in the bearing race/oil line leading to reduced and eventually stopped oil flow to the bearing, causing a complete failure of the turbo. Not worth the saved fuel cost. Now all that being said, there may very well be people out there driving in this way with turbos/turbo diesels that haven't killed their turbos, just out of luck I suppose. (I don't shut my engine down in my diesel, I just let it idle during the glide stage, it's 20 years old after all and barely road worthy).
One exception that I know of is with a ball bearing turbo, that requires no oil or cooling. These are much more expensive than oil bearing turbos and therefore not installed oem on any vehicles with turbochargers, AFAIK. This would be worry free P&G territory, unfortunately not financially feasible.
As a note on turbo timers, my understanding was that these are designed for people who take something like a Honda Civic with a tiny B18C engine and install a monsterized aftermarket turbo system and max out their engine tuning to get 300+ HP out of them. In this case there has been no multi-million dollar company engineering them to run properly with day to day operation, and they DO need to idle for a minute or two to cool the turbo down, especially in the drag racing/track environment in which they are used. Now take that baby through town and have to stop and sit in your car and idle for 1.5 minutes every time you get gas, smokes, take out, etc and you will be glad to spend some cash on a turbo timer to do the waiting for you.
If there was a theoretical electric oil/coolant pump that would remain on when I switched the engine off, that could be a blessing.
Still none of this addresses the fact that diesel costs 10 cents/Liter more in my area. Which is causing me to lean strongly in the gas engine direction, even though I have a soft spot for diesels.