balancing turbo assemblies

Poulina

Poulina

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Dec 2, 2015
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when swapping out wheels whether it be a turbine or compressor wheel on the same shaft, is it wise to have the entire assembly balanced? I'm moving down to a 67.7 cast wheel on my s400

down time and money are a factor, for me at least. a local turbo builder told me $200 to disassemble and balance, or i could just change the compressor wheel myself for $0 and a lot of anxiety haha. any insight or experience would be appreciated.
 
If you don't balance it, it will only live so long. If you do balance it, that time line is drastically increased.



I'm on a 64mm with 25k miles that still isn't pushing oil even though I assembled it. Its somewhere around the 550hp mark.



If you put it together, check it periodically for oil seeping or excessive play.





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biggy238 said:
If you don't balance it, it will only live so long. If you do balance it, that time line is drastically increased.



I'm on a 64mm with 25k miles that still isn't pushing oil even though I assembled it. Its somewhere around the 550hp mark.



If you put it together, check it periodically for oil seeping or excessive play.





Sent from mTalk
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This^^

You're gambling. Some assemblies I toss on the balancer are only 2-3x out of tolerance while others are 9-10x out.

It may live or it will eat the bearings up in a hurry. Ever put tires on yourself without balancing? Similar deal. Sometimes you get lucky. Except, this thing spins at 100k rpm.
 
Depends. On the component balance you balance on two planes. Inside of wheel or outside. When you do the assembly balance you take out weight on two planes as well but only 1 plane per wheel. Different machines want you to use different spots on the wheel. One of our machines wants it removed on the backside of each wheel during an assembly balance and the other wants it on the noses of the wheels.
 
This may be a dumb question, but could I use my motorcycle wheel/tire balancer to get much closer than just an assembly? I'm thinking I could toss the wheels on, see what side is heavy, and trim a little material off the but area like stock balanced chargers seem to be done.

1207160856a.jpg


Also, do you guys static balance, or dynamic balance where you take material off on both wheels in order to fight the 'non shaft axle' unbalance (Not sure the proper terminology here)?
 
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CorneliusRox said:
This may be a dumb question, but could I use my motorcycle wheel/tire balancer to get much closer than just an assembly? I'm thinking I could toss the wheels on, see what side is heavy, and trim a little material off the but area like stock balanced chargers seem to be done.

1207160856a.jpg


Also, do you guys static balance, or dynamic balance where you take material off on both wheels in order to fight the 'non shaft axle' unbalance (Not sure the proper terminology here)?
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Dynamic balancing. I would leave them be rather than attempt to balance them on a rig like that. We balance to .02 gram-inch on an HX35 for example. That is our target. We get them lower than that before we stop. That gives you an idea on what kind of weights and tolerances turbochargers deal with.
 
zfaylor said:
Dynamic balancing. I would leave them be rather than attempt to balance them on a rig like that. We balance to .02 gram-inch on an HX35 for example. That is our target. We get them lower than that before we stop. That gives you an idea on what kind of weights and tolerances turbochargers deal with.
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Yup, that's way way better than I can do in my garage!
Thanks for the schooling.
 
I agree. It is a bit odd. I imagine the fact that the gram is a more widely use unit of mass in engineering around the world has something to do with it though. Probably converted the distance to inches years ago for people in the states who thought the metric system was for communists.
 
While we are on the balancing topic, will it throw it out of balance if the compressor wheel is removed then put back on in a different location? Like a quarter turn out for example
 
Yes and no. Typically you do a component balance first. That gets the individual components (turbine wheel and compressor) balanced. Then you do an assembly balance (turbine wheel, thrust collar, flinger, compressor, and nut). That gets the assembly happy together. Typically marginal corrections are made during the assembly balance but there is definitely some imbalance present when you marry it all together. Stack up of tolerance plays a factor.

In short, yes it will throw it out of balance, but if it was all balanced correctly and maintained balance it won't be much.

Well used parts do not maintain balance very well, though.
 
I never understood the lure of wicked wheels from the whole balancing side of things.

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okie18 said:
I never understood the lure of wicked wheels from the whole balancing side of things.

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I agree.

I've yet to toss an assembly on the balancer and not have to make corrections. We get guys upset that we will not sell them a wheel. I didn't spend a copious amount of money on a balancer for my health. We want to believe in what we sell.
 
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