Turbo and trailering

Rowski · May 8, 2005

I picked up my TN yesterday at the dealer. Had a nice chat with the service manager talking about the TN series and tractoring. He asked me if I tape my exhaust pipe during transport. I told him I don't. He mentioned at higher road speeds the turbo can free wheel with out any lubrication. So he taped my exhaust pipe while I was securing the tractor on the trailer.

Is this something that can happen with turbos on tractors during trailering? Make some sense to me.

I know the TN pipes are vertical and bend forwards at the top. No way to really install an exhaust flapper.

Any thoughts?

Thanks

RoyJackson · May 8, 2005

I'd tape it...and, yeah, a turbo can free wheel. I'm not even going to try to get into the physics, but air moving over a surface does cause changes in pressures.

Anyway, I even cover my stack when the tractor is outside (setting idle) when it's raining.

caddison · May 8, 2005

Derek,

I have seen a lot of guy's leave their turboed units running while trailering for this very reason. I thought it was kind of odd when I saw a guy hauling a cat and it was running so I asked and he told me why. You could have a piece of exhaust pipe cut that is the same diameter as you exhaust, cap it and slide it over the end when hauling.

txhawg · May 8, 2005

I don't think this is true. I have read numerous things about this and I have never seen a big rig have his exhaust taped when being towed.

Anyway, having said that, you are better safe than sorry.

RickB · May 8, 2005

I won't tell you not to tape it, and I don't argue with those who think it is absolutely necessary. But I have yet to have anyone explain to me how a significant amount of air can flow past either side of the turbo without the tractor running. We don't have enough valve overlap to make a claer path in & out that would flow enough air to make the turbo turn, IMHO. If it makes you feel better, tape it. Certainly can't hurt.

LarryRB · May 8, 2005

depends how loaded on a trailer... If the exhaust faces into the wind or faces the pulling power, then they are taped or capped. If the exhaust faces to the rear then no... And yes, a long haul distance can and does fry the turbo bearings..

Av8r3400 · May 8, 2005

I don't want to be argumentative, but, where does the air coming down the stack, through the turbo (spinning it) go from there? There's no exit for it, is there? At least not enough to spin the turbo from the turbine side. Does this depend on an open exhaust and intake valve? I would agree that there is unlikely enough overlap in the cam timing of a tractor motor to allow enough volume of air to turn the turbo. Now, it may suck in enough rain to corrode and ruin the turbo bearings. Covering can't hurt, but, I don't see what it would do other than keep the water out.

This sounds like a myth to me. Where's the Myth-Busters when you need 'em. /forums/images/graemlins/grin.gif

Richard · May 8, 2005

</font><font color="blue" class="small">( where does the air coming down the stack, through the turbo (spinning it) go from there? There's no exit for it, is there? )</font>

My understanding (speculation) is that rather than the air coming DOWN, the "faster air" outside the top of the stack will sort of create a low pressure vaccume. As such, it will pull the air OUT of the stack, rather than push it in.

I was told (I have a flapper on top of my verticle stack) that you want the flapper to face the rear so the wind will help to hold it down, rather than if reversed, help hold it up and allowing the aforementioned fears/realities

/forums/images/graemlins/cool.gif

Taylortractornut · May 8, 2005

alot of excavaotrs have a rear facing exhaust and when trailered the counterweight exhaust end is toward the front of the cab of the truck to allow the boom to be faced towards the rear to keep from snaggin obstructions. The turbulence from the wind will move the turbos fan. I had a lowboy pull up beside me one job and tyou could hear the turbo on the excavator wind down. I taped up the ppe for them after they remebered about it.