Turbo cool down time

**mangostick** · 10-29-2010 06:23 AM

Originally Posted by kayma

Jeez, you guys act like subaru doesn't know what it's doing and is going to easily let everyone kill their turbos. Obviously they thought it out and you can stop worrying so much about them unless they were put in completely by yourself.

Jeez you've never had to replace a fkd turbo have ya? Or excessivly worn rings/pistons.. or jacked up main bearings..

Its expensive to hammer on something and just shut it off or hammer on it before its warmed up. I'll also add that no matter how well designed the oem makes the system .. they can and do fail when abused. Not properly letting a turbo/engine cool off DOES make a difference. Granted much less with a water cooled turbo but think about it, if you've just been wompin the piss out of the car, roll up and shut off.. that turbo is still spinning, without oil feed.. and that sir is NO GOOD. You are aware that the center shaft of your turbo spins at HUNDREDS OF THOUSANDS OF RPM RIGHT? It doesn't just stop when you turn the key off. It wont kill it right away, but keep that crap up and you'll have a failed turbo in no time flat .. let alone what that abuse does to the rest of the engine.

I treat my wrx just like I would any other car.. the turbo isn't the only part in the engine that needs warming/cooling prior to shutting off. Engines are precise devices that have very close tolerances and operating ranges. Work one hard outside of that range and stuff WILL eventually break. Its only a matter of time.

**SD_GR** · 10-29-2010 06:36 AM

Originally Posted by mangostick

Jeez you've never had to replace a fkd turbo have ya?

The Mitsubishi turbos are now on their third decade. How many units have failed due to coking? Consider that they are reliable enough for pro applications (in lorries) and that they are reliable enough for other makers to fit onto their cars. We're simply not seeing turbo failures due to poor shutoff practices at this point, meaning we are unlikely to ever see them.

**Donkey** · 10-29-2010 04:45 PM

Originally Posted by mangostick

Jeez you've never had to replace a fkd turbo have ya? Or excessivly worn rings/pistons.. or jacked up main bearings..

Its expensive to hammer on something and just shut it off or hammer on it before its warmed up. I'll also add that no matter how well designed the oem makes the system .. they can and do fail when abused. Not properly letting a turbo/engine cool off DOES make a difference. Granted much less with a water cooled turbo but think about it, if you've just been wompin the piss out of the car, roll up and shut off.. that turbo is still spinning, without oil feed.. and that sir is NO GOOD. You are aware that the center shaft of your turbo spins at HUNDREDS OF THOUSANDS OF RPM RIGHT? It doesn't just stop when you turn the key off. It wont kill it right away, but keep that crap up and you'll have a failed turbo in no time flat .. let alone what that abuse does to the rest of the engine.

I treat my wrx just like I would any other car.. the turbo isn't the only part in the engine that needs warming/cooling prior to shutting off. Engines are precise devices that have very close tolerances and operating ranges. Work one hard outside of that range and stuff WILL eventually break. Its only a matter of time.

Seriously? I mean really........how many people run up to redline and immediately shut of the car? None. By the time you pull into a parking space the engine/turbo is cooled down plenty. Not to mention most people are running synthetic oil. Your not running Lemans here people...............

**2:43AM** · 10-29-2010 06:26 PM

That's right, and if you say otherwise, the 8 active members of this forum will shut you down!

**mangostick** · 10-29-2010 06:49 PM

*face-palm*

no one? you sure about that? I'm not.. and wouldn't go anywhere near as far as to make a statement about it.
Sure, you and I aren't... but someone is, and that'll be the guy that comes on here asking why his turbo is squeeling and has side play so bad the compressor wheel is shaved down 1/16" cuz the center section is shot

Or better yet when the engine gets some mileage on it and they're *****ing about low compression or rod knock (excessive bearing wear) .. we all know 80% of wear is between start up and op temp...

But, thats ok I've never seen a bad turbo ever

, I've never built an engine .. I've never even held a wrench.. :/ I've never squeezed 400whp out of a forced induction 4cyl mill..

I've never made a buck rebuilding an engine that some ritard abused to death.

**2:43AM** · 10-29-2010 07:30 PM

^^^

Who you talkin 'bout, Willis?

**SD_GR** · 10-29-2010 07:32 PM

I don't think anyone is doubting your experience or skill. I can't speak for anyone else, but I will tell you in a nutshell what I am skeptical about instead -- and as always in the context of a friendly debate: longevity concerns at least with respect to modern Mitsubishi turbos used within their intended parms.

Sure, some guys will have issues on a stock car. It's really quite rare though; this isn't my first car (or online community) that uses Mitsu turbos, and stock failures are quite rare from what I can see. Other guys will have issues when they push beyond stock, and get out of the sweet spot in the graph etc. I'd expect that to happen more, only because in my biased view it makes more sense (the expected result fallacy I suppose applies).

All said though there are hundreds of thousands of vehicles out there using this turbo family and they generally do well, or at least well enough where the turbo isn't what limits the car's longevity. I think the same is true of our cars; I don't think the first major failure on a typical Impreza is the turbo.

EDIT: After I re-read my post to make sure it at least made some sense to me, and was happy with posting my oh-so-thought-out premise (sigh...) this thread comes up, within minutes!
http://www.clubwrx.net/forums/showth...=1#post2685123
Maybe it's the exception that proves the rule... I hope...

**Anub1s** · 10-29-2010 07:48 PM

Originally Posted by mangostick

*face-palm*

no one? you sure about that? I'm not.. and wouldn't go anywhere near as far as to make a statement about it.
Sure, you and I aren't... but someone is, and that'll be the guy that comes on here asking why his turbo is squeeling and has side play so bad the compressor wheel is shaved down 1/16" cuz the center section is shot

Or better yet when the engine gets some mileage on it and they're *****ing about low compression or rod knock (excessive bearing wear) .. we all know 80% of wear is between start up and op temp...

But, thats ok I've never seen a bad turbo ever

, I've never built an engine .. I've never even held a wrench.. :/ I've never squeezed 400whp out of a forced induction 4cyl mill..

I've never made a buck rebuilding an engine that some ritard abused to death.

That one idiot is one in hundreds of thousands that are smart enough NOT to do that, let him learn his lesson on his own. If he's stupid enough to continue, let him. I couldn't care less about the one idiot who thinks revving to redline and immediately shutting off his car is a good idea.

Once you are done doing whatever racing, and have made it to a safe place to park, your engine and turbo are equally cooled to the point where you don't have to worry about them. If you're running some monsterous turbo that is only oil cooled, then you have to wait, but most modern turbos do NOT need this extended cool down time, nor do the engines.

People are stupid, if they beat their cars before they're properly warmed up, there's going to be issues, that's always the case, and I see it in the dozens of cars I hear pulling out of my complex just after starting up, and they have a lot of rattling and even knocking from the engine bay. But cooling down is something that these cars are designed to do WHILE being beaten, once you're done and parked (given at least 30 seconds to a minute), there's no reason to keep it running. NONE. Period.

BTW that guy you yourself are *****ing about is the guy who's paying you to rebuild his engine. Let him be stupid if he wants to, it's his ****ing money.

Like I said earlier, it's the warm up period you should be concerned with, not the cool down. Your engine is designed to take care of that for you, and unless you're stupid enough to rev it up and immediately kill it, you'll be fine.

***mycologist*** · 10-29-2010 08:01 PM

I'm pretty easy on my car for the first 10 min. and stay out of boost for the last bit of the trip for the most part.

That being said, just make sure you don't run it out of oil and I think you'll be fine.

Oh, and this is the oldest thread I ever moved. Still not sure if that was cool.

**mangostick** · 10-30-2010 09:12 AM

Originally Posted by Anub1s

That one idiot is one in hundreds of thousands that are smart enough NOT to do that, let him learn his lesson on his own. If he's stupid enough to continue, let him. I couldn't care less about the one idiot who thinks revving to redline and immediately shutting off his car is a good idea.

Once you are done doing whatever racing, and have made it to a safe place to park, your engine and turbo are equally cooled to the point where you don't have to worry about them. If you're running some monsterous turbo that is only oil cooled, then you have to wait, but most modern turbos do NOT need this extended cool down time, nor do the engines.

People are stupid, if they beat their cars before they're properly warmed up, there's going to be issues, that's always the case, and I see it in the dozens of cars I hear pulling out of my complex just after starting up, and they have a lot of rattling and even knocking from the engine bay. But cooling down is something that these cars are designed to do WHILE being beaten, once you're done and parked (given at least 30 seconds to a minute), there's no reason to keep it running. NONE. Period.

BTW that guy you yourself are *****ing about is the guy who's paying you to rebuild his engine. Let him be stupid if he wants to, it's his ****ing money.

Like I said earlier, it's the warm up period you should be concerned with, not the cool down. Your engine is designed to take care of that for you, and unless you're stupid enough to rev it up and immediately kill it, you'll be fine.

^^exactly!

everyone wants to get carried away with the turbo cooling when its the warm up that counts more and not just for the turbo but he whole engine.

And granted I've not messed with too many mitsu turbo's.. but garrets, IHI, Holset.. worked with many of those in all varieties. I've found more failures in the IHI's than the others (some really spectacular ones too). Holsets have a really robust center section. Regardless spinning em up cold is never good. Even ball bearing turbo's dont like to be spun up cold though they deal much better with it.