Turbo etiquette
Discussion
In 2000 I had a Nissan 200SX S13 Turbo. I was religeous in allowing it to wind down after a fast drive and never just switching off the engine.
I have owned no turbo charged cars in the mean time until we bought a brace of diesel BMW's, and the whole turbo spinning after engine being shut off thing is not even mentioned!
Has there been an advance in technology or are people just not bothering?
Is this why some cars are reputed to 'use up' a turbo after x miles?
I am still treating the turbo in my 530d as I would have in an old petrol just out of mechanical sympathy. Am I right or wrong to?
I have owned no turbo charged cars in the mean time until we bought a brace of diesel BMW's, and the whole turbo spinning after engine being shut off thing is not even mentioned!
Has there been an advance in technology or are people just not bothering?
Is this why some cars are reputed to 'use up' a turbo after x miles?
I am still treating the turbo in my 530d as I would have in an old petrol just out of mechanical sympathy. Am I right or wrong to?
I've had a couple of TDs that I've done 60k+ in and never worried about it, although I can't think of a situation when I could come to halt and switch off fast enough that the turbo would still be running at high speed, home is on a 30mph road with parked cars, work has a wiggly bit on the way into the car park, so do motorway services.
I suppose if you're doing 70, slam the brakes on and quickly switch off you might, but really the only time you're likely to do 70 to 0 is when there's a motorway jam and you aren't going to switch off anyway. Maybe you would coming into the pits (except then you should know not to turn off immediately) but when on the road?
I suppose if you're doing 70, slam the brakes on and quickly switch off you might, but really the only time you're likely to do 70 to 0 is when there's a motorway jam and you aren't going to switch off anyway. Maybe you would coming into the pits (except then you should know not to turn off immediately) but when on the road?
Older turbo cars were oil cooled, so you risked coking up the oil drains in the turbo if the whole thing was stinking hot when you stopped. Reduced oil flow, less lubrication, less cooling = mashed bearings.
Since the mid 90s most of them have been water cooled and oil lubricated so they are a lot more tolerant to temperature change.
"Cooling down" turbo cars hasn't been a requirement for a long time now.
Since the mid 90s most of them have been water cooled and oil lubricated so they are a lot more tolerant to temperature change.
"Cooling down" turbo cars hasn't been a requirement for a long time now.
john2443 said:
I've had a couple of TDs that I've done 60k+ in and never worried about it, although I can't think of a situation when I could come to halt and switch off fast enough that the turbo would still be running at high speed, home is on a 30mph road with parked cars, work has a wiggly bit on the way into the car park, so do motorway services.
I suppose if you're doing 70, slam the brakes on and quickly switch off you might, but really the only time you're likely to do 70 to 0 is when there's a motorway jam and you aren't going to switch off anyway. Maybe you would coming into the pits (except then you should know not to turn off immediately) but when on the road?
It was never about the turbocharger itself spinning after shutdown, it was about heatsoak in the turbine chrystalising the engine oil trapped in the bearings. Idling the engine for a period after running boost kept oil circulating through the turbocharger bearings to carry the heat away from the turbine.I suppose if you're doing 70, slam the brakes on and quickly switch off you might, but really the only time you're likely to do 70 to 0 is when there's a motorway jam and you aren't going to switch off anyway. Maybe you would coming into the pits (except then you should know not to turn off immediately) but when on the road?
In my very limited experience of turbines (gas and steam in warship propulsion). I remember an engineer talking to me once about the similarities with a car turbo, only much bigger.
It was somthing to do with the turbine rotors being made of a different metal to the casing, and them contacting at a different speed. You don't want the two to touch so you cool them down while spinning.
It was somthing to do with the turbine rotors being made of a different metal to the casing, and them contacting at a different speed. You don't want the two to touch so you cool them down while spinning.
RobGT81 said:
The VAG 2.0L FSI has an aux coolant pump that keeps running if you shutdown hot, I presume other versions do too.
I've noticed that something "fan-like" continues running on the OHs V70 (2.5 Turbo) when the engine is switched off; I always presumed it was something to do with turbo cooling.I would say there is a certain level of etiquette to caring for your turbo if you want to get the most from it and possibly extend its working life.
Personally I would sooner change the oil and filter more regularly rather than sitting in the car letting it idle for a few minutes after driving.
Do that whilst youre not moving and the car may start getting hotter with no air passing through the radiator or oil cooler. Just make sure the car returns to normal idle speed once you have stopped then switch off.
You are unlikely to prevent a build of crystalised oil deposits in the bearings no matter what you do as heatsoak cannot be eliminated so to some extent you will always cook your oil and water unless you have some kind of timer device fitted.
Some folk also fit pre-filters to the oil feeds as added protection from debris fouling up the bearings.
Always let the engine reach its normal working temp when starting from cold before using any boost. Cold, thick oil is one sure fire way of killing the bearings.
Personally I would sooner change the oil and filter more regularly rather than sitting in the car letting it idle for a few minutes after driving.
Do that whilst youre not moving and the car may start getting hotter with no air passing through the radiator or oil cooler. Just make sure the car returns to normal idle speed once you have stopped then switch off.
You are unlikely to prevent a build of crystalised oil deposits in the bearings no matter what you do as heatsoak cannot be eliminated so to some extent you will always cook your oil and water unless you have some kind of timer device fitted.
Some folk also fit pre-filters to the oil feeds as added protection from debris fouling up the bearings.
Always let the engine reach its normal working temp when starting from cold before using any boost. Cold, thick oil is one sure fire way of killing the bearings.
amusingduck said:
Out of curiosity, does anyone know whether the VAG 1.8T (BAM/AGU/AUQ/etc) engines have water cooled turbos?
The BAM engine is certainly water cooled - there is a small secondary electric water pump that you can hear a faint buzz as it continues to circulate water through the turbo for a while after you turn off when it's warm - at least that was the case on my 2004 Leon Cupra R.I'll run mine for a minute or two before turning off if I stop at services on the motorway.
Otherwise I've got a few miles of 30's to get home so the turbo isn't going to be meltingly hot and where I live I turn round further up the road and coast back (downhill) to the house so the car always gets an extra 30s or so of off boost just over tickover running before I stop anyway.
Otherwise I've got a few miles of 30's to get home so the turbo isn't going to be meltingly hot and where I live I turn round further up the road and coast back (downhill) to the house so the car always gets an extra 30s or so of off boost just over tickover running before I stop anyway.
ToothbrushMan said:
Always let the engine reach its normal working temp when starting from cold before using any boost. Cold, thick oil is one sure fire way of killing the bearings.
This, this and a bit more of this. Recently ran this on a test cell at an oil temp of 60 degrees C, this is how it looked after about an hour.
Art0ir said:
No boost until oil up to temperature, no boost for the last few miles/3-4 minutes of the journey and most importantly good quality oil replaced every 5k miles.
This^^^^ 100%I also let mine idle for a min or two prior to switching off (I do this with all turbocharged units I drive).
I got into the habit with my old stage 1 Volvo T5, It is a good habit to be in.
I Don't really care if it is unnecessary tbh.
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