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99 stb
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Discussion Starter #3
that says for 2002 engines onwards doesnt it?
im not saying your wrong, but im a bit dubious of thrashing a turbo engine then just turning the ignition off............
 

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2009 Forester
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I don't have a turbo on my Subaru, but my dodge truck has one - its a Cummins 5.9 lt. diesel. My exhaust gas temperatures (I have a temperature guage with the probe post turbo) are running in the 450 degree F range when I pull up to park (this is without a load). I let it cool down to 325 degree F before shutting it down, takes about a minute and a half idleing. Since oil will cook a little higher than that, it saves the bearings in the turbo. I beleive that a gasoline engine runs hotter than a diesel, than everytime you shut down hot, you are cutting the life of your turbo. This is my opinion.
 

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2004 fxt A/T
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2,567 Posts
There is absolutely no need for a turbo timer on a modern subaru engine as stated by Peaty's link above. The coolant will reverse siphon from the right cylinder head, through the turbo,and eventually to the overflow tank. Our turbos are COMPLETELY different than the Cummins diesel turbo quoted above which is only oil cooled and thus EGT's must drop before turning the car off. Unless you are running the early Greddy oil cooled 18g or Garrett oil only CHRA there is no need. If you don't believe us fine put on a turbo timer and waste gas. You can read this article if you like, it does reiterate what is stated above.
 

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Well every turbo car i have had i have got a turbo timer fitted.
Weather it standed or not.
As i see it its not going to do any damage even if it don't need one.

but reading what Peaty put mabe im wrong.

These subaru seem to be a total diffent car.
 
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I am on my second subaru turbo charged car, never fitted a turbo timer or ever warmed up or cooled down and never had any problems.
Sorry I can't recommend you one..:cool:
 

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Don, King of the parts diagram
MY11 WRX STi Sedan 6MT
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that says for 2002 engines onwards doesnt it?
im not saying your wrong, but im a bit dubious of thrashing a turbo engine then just turning the ignition off............
AFAIK That's because the US didn't get a turbo'd motor until 2002.

It's water cooled for that reason :biggrin:
 

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2009 Forester XT Limited
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376 Posts
I could be mistaken but I thought I had read somewhere in the manual that you should idle the vehicle for 30 seconds or so prior to turning it off after driving long distances or running it particularly hard if you have a XT.

For what it's worth, I found these comments interesting.

(This first one was edited for more clarity)

As said here already no real need to idle down long in most conditions in a modern turbo app with water cooling and I'd imagine even without water to oil cooling so long as you drive it down like coming into your development. However, you want to allow the turbo time to stop spooling so you don't shut it off while it is still moveing without oil circulating over it. I personally allow about 15 seconds of so for this.



There's a good Mobil 1 video on youtube that shows the coking deposits on a turbo. Early saabs used to recommend idling for 30 seconds before shutting down to prevent oil starvation and for cooling. Those turbos ran around 90,000 rpms as I recall and if you shut it off immediately like Gary was talking about say from the highway or hard driving, the oil supply is shut off while it is still spinning at a very high rpm. Probably not as much of an issue with more modern turbos however. The newer VAG cars continue to circulate coolant after the car is shut off for quite a while. I know the vw 2.0 FSI does but I don't know about the 1.8T.


For an oil and water cooled turbo it isn't as big of a deal. I still wouldn't do a hard WOT highway pull and shut it down quickly thereafter. I think Subaru advises to idle the engine for 30 seconds or something before shutting it down after a long highway trip or hard driving.
 

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admin
2019 3.6R & 98 Forester Atlanta, GA
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I could be mistaken but I thought I had read somewhere in the manual that you should idle the vehicle for 30 seconds or so prior to turning it off after driving long distances or running it particularly hard if you have a XT.
I agree but I don't remember reading that anywhere. Isn't it pretty much common sense to do that with any motor?
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
I was under the impression that Subaru themselves had said that this cooling down practice was now unnecessary due to the vast improvement in modern oils since in the '00s vs the '90s.
 

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98 JDM Stb Manual
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3,787 Posts
I just drive off boost for the last 2 miles to my house
 

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1999 forester s turbo
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I think the fact that Subaru make family cars that get driven to the shops/work and back (Yes even the STI.) And not racing cars tell you all you need to know about them and the need for items that are race car specific. You can add race specific parts to your car but they are not really needed. They are built to last for ever without the need for add on parts. Even if you thrash the bollox off it. Think, a standard EJ20 engine can be pushed to over 400 HP so the over engineering is phenomenal.
 

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01 UK S-Turbo AT
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ditto the above. the foz is a family wagon. in standard spec I can't ever imagine Subaru deciding it would be a good idea to apply a turbo and associated bits that needed 'running down' before ingnition cutoff. I am on 120,000 miles, I drive like a granny and like a boy-racer (where local laws and conditions permit) with no apparent signs of abnormal turbo behaviour. Even after a shut down after a 'mega-fuel-burn' over the hills and dales (greater load..?) the engine temp indicator doesn't deviate from 'NORMAL' position. My only (subjective, non-scientific) concession to engine wear is the last 5 mins of any drive is taken lightly (I live in a city as well so this helps).

Don't worry about it!

Mike
 

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99 UK S-turbo
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Turbo timers are from when turbo's had no water cooling and shoddy oils, the oil baked in the turbo after switch off and clogged up with 'coke' you just don't get this on modern turbo's due to both the cooling and better oils, the 2 TF035's I stripped had no coking in the oilways at all.

My last mile home is in a 30 limit, so 2 mins at low speeds is my extra security.

Simon
 

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2008 GRB 20th anniversary 6 MT
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Simon, is this enough time for the exhaust gas temperatures to drop?
I was told this is the only way to see if a turbo has cooled down.
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
Simon, is this enough time for the exhaust gas temperatures to drop?
I was told this is the only way to see if a turbo has cooled down.
Exhaust gas temperatures get a lot lower if you turn the engine off :Banane36:
 
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