Oil to turbo on shutdown?

[Thedoityouselfguy]

Was talking to a fellow a while ago and he said "make sure you install an electric accessory oil pump t provide oil to the turbo after shutting your engine off as it is still spinning". I assume this would probably do the most damage when you are fully spooled and you flip or fall off your Nytro? Or is this guy just plain nuts? Says its a pump that usually runs a few seconds after engine kill to lubricate turbo.

 

[teeroy]

sounds like one of the old school mechanics that insist you plug an exhaust so a turbo doesn't spin on the lowbed....

 

[Stg2Suby]

I've never heard of that, what are this guys credentials? Some vehicles will run an aftermarket timer to keep the motor running after you pull the key and walk away, but this was to prevent the heat of the turbo from coking the residual oil film left in the journal bearings. Doesn't apply if 1) the turbo is water cooled or 2) it's a ball bearing vs journal bearing design (could be wrong on 2, please correct me if so).

 

[Thedoityouselfguy]

sounds like one of the old school mechanics that insist you plug an exhaust so a turbo doesn't spin on the lowbed....

Ha ....that is actually true on older equipment like cats and whatnot. Usually newer smaller equipment like bobcats and whatnot do not have that issue though.




But back on topic.....you would think that there would be enough oil I the supply lines on a rear mount turbo to provide enough lubrication? I can't see all the oil just simply draining. I don't know....someone enlighten me.

 

[teeroy]

Ha ....that is actually true on older equipment like cats and whatnot. Usually newer smaller equipment like bobcats and whatnot do not have that issue though.

the reasoning that fella told you that there needs to be a pump is based on the same assumption of the equipment turbo wive's tale. you were correct in that the only scenario there could possibly be an issue with your situation is if you were at full boost for a period of time that your turbo and exhaust had reached it's maximum operating temperature and immediately shut down with the turbo spinning at 100,000+ rpm (or whatever the max rpm of a snowmobile turbo is). at that temp fresh oil circulation is critical to avoid burning the oil and leaving coking deposits on the bearings.

 

[aiden1983]

I've never heard of that, what are this guys credentials? Some vehicles will run an aftermarket timer to keep the motor running after you pull the key and walk away, but this was to prevent the heat of the turbo from coking the residual oil film left in the journal bearings. Doesn't apply if 1) the turbo is water cooled or 2) it's a ball bearing vs journal bearing design (could be wrong on 2, please correct me if so).

You are correct with #1 (dependent on how the water is pumped) but point #2 is incorrect (ball bearing turbos still need cooling). As others have pointed out, if you came off the sled or killed the engine in one way or the other at WOT then you can cook the oil and create a residue in the bearing race/journal. Also if you ride the sled hard and create a cherry red turbo and then shut it off right away it will not turn out well either.