Turbo Cool-down

   / Turbo Cool-down #1  

HK416

New member
Joined
Sep 3, 2009
Messages
19
Location
Lower Alabama
Tractor
Kubota MX 5100 4x4/HST/FEL
I just sold my L3130 and am awaiting delivery of my new MX 1500 in a couple days. Since I haven't received my owner manual yet, would you turbo owners chime in and tell me how much cool-down/idle time I need to do after running the tractor at normal operating speed? How about after I've run the tractor hard (bush-hogging)? Thanks!

-Podunkadunk
 
   / Turbo Cool-down #3  
I do this with my B2320. After Im working at full load i take it on a easy drive to let the rad. circulate air and cool the coolant down even more. Is it a must? Im sure not but, it does bring the temp down on the coolant gauge.
 
   / Turbo Cool-down #4  
The cool down is to get to a temperature that is low enough not to carbonize or "coke" the oil around the turbo's bearing. The oil stops flowing when the engine is cut off, so it is going to get as hot as the turbo itself while it sits there.

As I recall, 5 minutes at low idle should do the trick, if you are not just finished with heavy use. If it's just been run real hard, give it a bit more time to be on the safe side.

Nick
 
   / Turbo Cool-down #5  
If all of that extra running is really required, all I have to say is d*** stupid EPA. How much extra fuel and pollution is caused by that idle running?

The M9540 only gains one additional horsepower with the turbo. EPA forces the turbo requirement.:mad:

For me, I take the equipment back to the barn at a slow RPM and maybe give it 30 seconds before turning it off.

I'll have to check my pickup owner's manual but I don't remember any requirement to let it idle for 5 or 10 minutes every time I drive the truck anywhere! I can't imagine having to sit at idle for five or ten minutes every time I use it.

Ken
 
   / Turbo Cool-down #6  
It all depends on heat and speed. If you have been working the engine and the exhaust temps are up then your turbo will be spooled up too. The idea is to cool the turbo down and let it spool down. Heat cooks the oil when it is shut off hot and the speed will use up the oil supply as it spools down. If it has too much speed the bearings will run dry and with the heat coke the oil.
Idling around requires little cool down. 1 min is ample. Hard work requires 5 min or more. And not just for the turbo, as the engine temps should be allowed to stabilize also.:thumbsup:
 
   / Turbo Cool-down #7  
The cool down is to get to a temperature that is low enough not to carbonize or "coke" the oil around the turbo's bearing. The oil stops flowing when the engine is cut off, so it is going to get as hot as the turbo itself while it sits there.

Are the temps in a turbo higher than the temps in the cylinder? Why doesn't the oil carbonize in the oil scraper rings, on the cylinder walls, and in the passageways between cylinders up to the head?
 
   / Turbo Cool-down #8  
1) The combustion chamber is the hottest place around, but I'm VERY sure you already knew that.

I'm still not sure I know it. Turbos spin at 100K+ rpm, and they're driven off exhaust gases, doesn't seem impossible that local temps could rival combustion temps. I've never owned a turbo before, it seems strange that such a sophisticated piece of equipment is dependent on people sitting in their cars and tractors with the engine idling to cool it off. Do people carry magazines in their glove box to read while they cool down their saabs?
 
   / Turbo Cool-down #9  
If all of that extra running is really required, all I have to say is d*** stupid EPA. How much extra fuel and pollution is caused by that idle running?

The M9540 only gains one additional horsepower with the turbo. EPA forces the turbo requirement.:mad:

For me, I take the equipment back to the barn at a slow RPM and maybe give it 30 seconds before turning it off.

I'll have to check my pickup owner's manual but I don't remember any requirement to let it idle for 5 or 10 minutes every time I drive the truck anywhere! I can't imagine having to sit at idle for five or ten minutes every time I use it. Ken

if it is turbocharged then it IS in the owner's manual!



Are the temps in a turbo higher than the temps in the cylinder? Why doesn't the oil carbonize in the oil scraper rings, on the cylinder walls, and in the passageways between cylinders up to the head?
but the block is water cooled and does transfer heat away from everywhere else but the turbo. that is unless the turbo is water cooled too.


1) I thought maybe you were pulling my leg on this and trying to set me up.

2) Combustion comes first. Things only cool down after that, but the turbo temp is definitely up there.

3) No they send text message or use their cell phones. :) The cool down isn't that big of an issue. Often you finish your work, cut the RPMs and loaf back to your parking area. That can provide most of your cool down time. In the case of the Saabs, they probably aren't really being worked before being shut off. Some manufacturers have even provided an oil reservoir that supplies oil to the turbo after the engine is shut off.
not necessarily, some are actually HIGHER in the manifold! one example is a Dodge Cummins during an active regen since fuel is still burning in the exhaust to raise the temps to initiate the regen.
most if not all newer automotive Turbocharged cars are also using water cooled turbos. which makes the cool down time not as critical. it is still recommended though.
 
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   / Turbo Cool-down #10  
I'm still not sure I know it. Turbos spin at 100K+ rpm, and they're driven off exhaust gases, doesn't seem impossible that local temps could rival combustion temps. I've never owned a turbo before, it seems strange that such a sophisticated piece of equipment is dependent on people sitting in their cars and tractors with the engine idling to cool it off. Do people carry magazines in their glove box to read while they cool down their saabs?

As has been said most of the time the cool down happens as you park, unhitch, etc. The time a meaningful cool down is required is immediately after a hard workout. And even a non-turboed engine should be cooled down as many internal engine parts should have the temps stabilized before shut down. That time is dictated mostly by engine size (weight). A 2000# engine requires more stabilization time than a 200# engine.:thumbsup:
 
 
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