Turbo Care

[Dream to fly]

Its in writing so it must be true!  Just remember a thread a few weeks ago about turbo cooling and shut down.  I replaced one today on a truck that the customer bought from NAPA and this was in the box.  So I decided to share.

 

PS.  I have no idea why it rotated when I pasted it to the page

[jaylw314]

Most turbocharged cars today have turbine blades that are lubricated by engine oil and cooled by engine coolant, so the warm up/cool down is not necessary.  My car has a 4 cylinder engine factory turbocharged to 300 hp (a Subaru WRX STI), and the user manual does NOT recommended any warm up/cool down.  Still going strong 12 years later.  I remember a friend, though, with an old turbocharged Volvo who did have to cool down for a minute before shutting down.  Presumably, that turbo was not water cooled.

[N201MKTurbo]

There are a lot of turbo designs. You cannot apply any advice for one to all turbos. As far as turbos we will run into the Garrett turbos should be cooled down the Rayjay turbos not so much. The reason is that they have different bearing designs.

The one thing you don't want to do is over temp the TITs. That will melt your turbine wheel and/or crack your turbine housing. Not too dangerous, but $$$!

[peevee]

1 minute ago, N201MKTurbo said:

 

The one thing you don't want to do is over temp the TITs. That will melt your turbine wheel and/or crack your turbine housing. Not too dangerous, but $$$!

nothing sounds less dangerous than a tiny flamethrower cutting anything in its way under your cowl

[N201MKTurbo]

Just now, peevee said:

nothing sounds less dangerous than a tiny flamethrower cutting anything in its way under your cowl

Only slightly worse than the normal radiant heat from that thing.

Have someone run it up at full power on a dark night some time, with the cowl off, and look at that thing glow red hot!

[peevee]

4 minutes ago, N201MKTurbo said:

Only slightly worse than the normal radiant heat from that thing.

Have someone run it up at full power on a dark night some time, with the cowl off, and look at that thing glow red hot!

yeah, true.

I think richard collins had an article about his p210 breaking a vband and flame cutting through his cowl.

[N201MKTurbo]

10 minutes ago, peevee said:

yeah, true.

I think richard collins had an article about his p210 breaking a vband and flame cutting through his cowl.

I can see that, but that could happen with any exhaust leak. The exhaust pressure is probably a bit higher ahead of a turbo so it would be a bit more violent. All of the cracked turbine housings I've seen were just cracks in the casting. none were to the point where there was an open hole in the housing. If it got to that point it would probably stop the turbine and you probably wouldn't have to worry about hot exhaust gasses as much as finding a suitable landing spot.

 

I knew someone who had a catastrophic turbo failure in a 231. He couldn't get more than 10 in. of manifold pressure after it failed. He was able to fly to an airport safely and land normally, although very slowly.

Edited August 30, 2017 by N201MKTurbo

[Yooper Rocketman]

2 hours ago, N201MKTurbo said:

I can see that, but that could happen with any exhaust leak. The exhaust pressure is probably a bit higher ahead of a turbo so it would be a bit more violent. All of the cracked turbine housings I've seen were just cracks in the casting. none were to the point where there was an open hole in the housing. If it got to that point it would probably stop the turbine and you probably wouldn't have to worry about hot exhaust gasses as much as finding a suitable landing spot.

 

I knew someone who had a catastrophic turbo failure in a 231. He couldn't get more than 10 in. of manifold pressure after it failed. He was able to fly to an airport safely and land normally, although very slowly.

Been there, done that!

[peevee]

26 minutes ago, Yooper Rocketman said:

Been there, done that!

yuck.

[aviatoreb]

2 hours ago, Yooper Rocketman said:

Been there, done that!

In your rocket?  Please share.

[aviatoreb]

5 hours ago, jaylw314 said:

Most turbocharged cars today have turbine blades that are lubricated by engine oil and cooled by engine coolant, so the warm up/cool down is not necessary.  My car has a 4 cylinder engine factory turbocharged to 300 hp (a Subaru WRX STI), and the user manual does NOT recommended any warm up/cool down.  Still going strong 12 years later.  I remember a friend, though, with an old turbocharged Volvo who did have to cool down for a minute before shutting down.  Presumably, that turbo was not water cooled.

I also have a subaru WRX-STI.  I run it at -30F and 90F.  I turn it on and drive.....and then when I get there I turn it off.

[jetdriven]

Same here. Turbo BMW and before that a Turbo Eagle Talon. Just drive like grandma the last minute and shut it down when you stop. 

[Yooper Rocketman]

1 hour ago, aviatoreb said:

In your rocket?  Please share.

https://mooneyspace.com/topic/17176-engine-failure-fl190-yesterday/?tab=comments#comment-246662

 

[kmyfm20s]

6 hours ago, peevee said:

yeah, true.

I think richard collins had an article about his p210 breaking a vband and flame cutting through his cowl.

I had a friend have that happen to their T210. Ended up in a successful dead stick landing.

[N201MKTurbo]

Glad I fly a Mooney and not a Cessna

[jlunseth]

There are two or three things to check during pre-flight that might help with these problems.  First, my 231 has a small access door to the turbine on the right side, if you don't have a door like that, checking the turbo will be harder.  First, I just look at the turbo.  If the housing is cracked there will usually be a gray powder or film on the turbo.  Don't ask me how I know that.  Second, it is worth sticking your finger into the exhaust and rubbing on the inside of the exhaust to see what you get.  If it is dirty and dry, that's good.  What you don't want is oily, grimy, which indicates a leak in the turbo.  Last, just take the end of the exhaust in your hand, watch the turbo through the door, especially in the area of the band, and see if slight pressure on the exhaust will cause any movement.  It should not cause any movement at all.  Obviously, you don't want to apply a ton of pressure but a little does not hurt.

[aviatoreb]

yikes, that is scary.

I have my annual coming up in late Oct.  What can I ask to help a bit to mitigate the risk of that?

Is there anything I can check during preflight, or in flight to help mitigate the risk of this?

Edit: jlunseth I see you answered some of what I asked while I was still responding.  Thanks!  Still I leave the questions up for further input.

Edited August 31, 2017 by aviatoreb

[peevee]

39 minutes ago, aviatoreb said:

Edit: jlunseth I see you answered some of what I asked while I was still responding.  Thanks!  Still I leave the questions up for further input.

doesn't help much with the rocket, the turbo is mounted below the oil pan and not to the side like the 231. All you can see through the door is some scat tubing and the engine mount most likely. All you can really do is inspect the turbo, vband clamps, and safety wire at each oil change. First change, our vband clamps weren't even safety wired. @Yooper Rocketman suggested in his thread to check the shaft play through the filter screen, that's probably good advice, though at what level of play is acceptable I do not know. I've had brand new automotive KKK (borg warner, not the klan) turbos (03 and 04) with at least a little shaft play.

[carusoam]

Great picture kmy.  The broken band is still hanging on the exhaust pipe...

The exhaust pipe between the engine and turbo is most critical.  Hottest and highest pressure gasses.  If you can only inspect one thing the V-bands on this pipe are worth the extra look.  This particular pipe also sees the most wear/age related thinning.  The heat of this pipe is not very friendly to its metallurgy....

failed V-bands often occur after maintenance.  Some limitations in use and retorquing may apply...  The Bravo's bands come to mind...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Greg_D]

The turbo in most cars will cool down with the engine at idle.  In an airplane, the turbo stops cooling just about the time the wheels touch down on landing.  Idling the engine after stopping just heats everything up again, including the turbo.