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Discussion Starter · #1 ·
I'm curious how you guys go about cooling down the turbo after a spirited or normal drive.

Normal driving I usually idle for 30-45 seconds... During this time after I've parked I normally spend time gathering up all my belongings (ie: phone, wallet, iPod etc).

Spirited drives I will tend to drive normally for the last 5-10 mins followed by idling for about 1.5 - 2 mins.

Don't know if it's overkill, not long enough or whatever but I dont want the oil to bake in the turbo.

What procedure do you guys follow?
 

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i don't let mine sit that long so i'm sure you're fine and i've got maybe 23,000 miles on my car and about 6,000 miles running 24psi
 

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I just drive at a normal pace for the last 5 - 10 minutes of the drive home, and that seems to be enough for me. I'm not blasting it back home all the way as, well, you're on normal city streets and shouldn't be driving like a loon at that point.
I did the same thing when I had my impreza, and I think I thrashed that way more than I do my F5, and it was ok. I did have a turbo timer in it, but it was usually turned off as the car was so loud at idle that it'd annoy people if I let it sit.
 

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I am glad you brought it up.

I was wondering the same thing. How long should I let it "cool off".

So, I started monitoring the car/engine.
I realized that in normal driving, typical everyday, city/highway... the pressure barely reaches 0, maybe goes into 5 PSI.
I was monitoring boost pressure while going on highway. At 65 MPH it was in deep vacuum (-15 in Hg). At 70 MPH it went to about -10 in Hg. At 80/85 it was getting to about -5 in Hg, sometimes closer to 0, but this time it was also heavy use of A/C.

Hence, since the turbo does not compress the air, it does not get hot. Not any hotter than at idle.
Same in the city. If under load I get for a few seconds +10 PSI, it drops to -15 in Hg at steady speed of 40-50 MPH. Then coasting... -22 in Hg.


Therefore, I realised it is not needed to let it idle. Unless I let the turbo to spin and do lots of compression.

Correct me if I am wrong in this thinking.
 
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Me neither but I'm no Rocket Surgeon. I think once you're modding, it may be a good idea to get a turbo timer or whatever they're called. I do recall reading somewhere that the new cars with twin-scroll do not need the cool down period because the false-safe is designed into it. Something like that, lol.

I am glad you brought it up.

I was wondering the same thing. How long should I let it "cool off".

So, I started monitoring the car/engine.
I realized that in normal driving, typical everyday, city/highway... the pressure barely reaches 0, maybe goes into 5 PSI.
I was monitoring boost pressure while going on highway. At 65 MPH it was in deep vacuum (-15 in Hg). At 70 MPH it went to about -10 in Hg. At 80/85 it was getting to about -5 in Hg, sometimes closer to 0, but this time it was also heavy use of A/C.

Hence, since the turbo does not compress the air, it does not get hot. Not any hotter than at idle.
Same in the city. If under load I get for a few seconds +10 PSI, it drops to -15 in Hg at steady speed of 40-50 MPH. Then coasting... -22 in Hg.


Therefore, I realised it is not needed to let it idle. Unless I let the turbo to spin and do lots of compression.

Correct me if I am wrong in this thinking.
 

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Tuned bolted or not - does not really matter. What matters is how heavily it is used when you are driving. Even, non-turbo car - when driven hard should have some time to cool down. If you push it - it gets hot. If you drive normally, it stays in normal temp and idling will not make it any better. I believe it may make it worse.

Oil cooler does not have air flow when stationary, hence oil will start getting hotter. FMIC, or stock cooler, gets hotter as well (no air flow). Air intake starts picking up all the heat that will travel through the compressor anyway... so overall it gets hotter.


There are different approaches.
Coolant circulation or oil circulation or combination. Or idle timer.

I have a friend with Audi V6 2.7T. The fans can kick in minutes after the engine shut down. The coolant is circulated...
I honestly do not think it is needed when driving at normal pace/rate. If you were racing - you know what to do then.
 

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There is no need for a turbo timer, or letting your car idle with these vehicles. There is ample air flow, along with liquid, and oil cooling. Turbo timers have really not been needed since the 90's. Some people prefer to use them for peace of mind. But the necessity is not there. Not to mention that many newer cars will still use the fans and circulate coolant while the vehicle is turned off if need be. One of the comments related heat to use of boost, while this is true that it will get hotter when it is getting beat on, ALL of your exhuast still flows through the manifold/turbo whether you are boosting or not. So the turbo is going to get hot either way. Constantly boosting will raise your EGT, but will drop your BAT's.

Short answer is, no it is not needed. But if you choose to that is fine, there is no damage done either way. As most of these new turbocharged vehicles are built originally with fuel economy in mind, and not necessarily an enthusiast car, they design them to be stupid proof (within reason)
Tyson
 
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Yeah no explicit cool down period for me. But I don't tend to hoon in my own neighborhood or by work so I'm just naturally taking it easy at the start and end of my drives.
 

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Same applies if and when one of us decides to upgrade the turbo? what's the consensus then? I've seen threads from people in other boosted cars upgrade in ng their stock turbos and wondered if that is relevant or not.
 

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Discussion Starter · #11 ·
There is no need for a turbo timer, or letting your car idle with these vehicles. There is ample air flow, along with liquid, and oil cooling. Turbo timers have really not been needed since the 90's. Some people prefer to use them for peace of mind. But the necessity is not there. Not to mention that many newer cars will still use the fans and circulate coolant while the vehicle is turned off if need be. One of the comments related heat to use of boost, while this is true that it will get hotter when it is getting beat on, ALL of your exhuast still flows through the manifold/turbo whether you are boosting or not. So the turbo is going to get hot either way. Constantly boosting will raise your EGT, but will drop your BAT's.

Short answer is, no it is not needed. But if you choose to that is fine, there is no damage done either way. As most of these new turbocharged vehicles are built originally with fuel economy in mind, and not necessarily an enthusiast car, they design them to be stupid proof (within reason)
Tyson
Very interesting. Thanks Tyson - for peace of mind I'll still idle down a little bit, but not as long I suppose haha
 

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ALL of your exhuast still flows through the manifold/turbo whether you are boosting or not. So the turbo is going to get hot either way.
I was under impression wastegate directs the flow to bypass compressor when boost is not needed. Hence, the spool sound. Where am I wrong?

Not to mention that many newer cars will still use the fans and circulate coolant while the vehicle is turned off if need be.
For sure it is not on KIA. As I mentioned above, friends 2001 Audi does have one. So far it did not fail... yet there were many complains from VW family of leaking pumps and draining batteries.

That would be a nice solution here - thermal switch and electric pump allowing coolant flow when compressor/engine get too hot after shut down.
 

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I just take a little extra time to just let it idle before I shut down and I make sure I keep up with oil changes before I have to.
Earlier the better.
 

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Same applies if and when one of us decides to upgrade the turbo? what's the consensus then? I've seen threads from people in other boosted cars upgrade in ng their stock turbos and wondered if that is relevant or not.
So long as it is still a water/oil cooled turbo, which i would assume it would be. You should be good.
Tyson
 

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Shutting down with a CVVT oil temp under 200 F is never a bad idea.

The time it takes to run a torque app CEL diagnostic is a perfect turbo timer.
 

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Instead of idling, simply drive it gently the last couple of minutes. With the additional air flow, it will cool more than just sitting there idling. I've had a '93 Eagle Talon, 2006 Audi A4 and now this car turbocharged and never had any problems. Now if you do have to stop driving immediately after a lot of boosting, then ya, I'd give it maybe 1 minute of idling at least, but even then if you change your oil regularly, like NEVER more than 5000k miles, you should be fine.
 
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