This is probably a re-post, but a ball-bearing turbo, assuming that the use is normal, how long do they usualy last? How does one examine the used turbos to see if they are worth buying? Also, in a used turbo kit driven for let's say 15-20k miles, what is worth keeping, what should be replaced? I just want to have this info on me in case something pops up in the marketplace section.
Thank you.

 

A ball bearing turbo should last as long as your car... That said, the weakest link in the system is the oil seals and you can only check them by taking that whole thing apart (or instal it and see how bad your exhaust smokes or how much oil you get in the interooler )

I can't think of any part of a TT kit that can't be reused. You might want to replace the hoses (anything rubber or silicone) but they should last a while as well.

 

+1 Turbonetics just recieved back a T3 ball bearing turbo from a customer with 150,000 miles on it. Hadn't even been rebuilt...

 

The only way to check, is to have the entire turbocharger center section disassembled, examined, etc...its not cheap to do. There are obvious signs of damage, that can be observed from the outside, such as oil residue, chipped blades, overly loose shafts etc.

 

This is going to be a really dumb question, but these kinds of damage, do they occur b/c of built-in defects or b/c of poor maintainance?

 

Could be both. It depends on the manufaturer but usually damage is due to poor maintenance/usage. For high power oil cooled turbos you need to ensure you observe proper cool down times when the car is run hard. A turbo timer can do this for you of course. With proper cool down times and regular oil changes (every 3k miles or less) your turbos should last as long as your car does. This of course is hinging on the fact that the turbo kit design provides enough oil to the turbo and a way for the oil from the turbo to exit. One of the processes that Turbonetics does to ensure a good turbo from them is they balance the turbo at every stage of assembly. First the compressor wheel, then the turbine wheel, then the shaft, then the bearing assembly, then the completed assembly, then when the turbo is finally assembled the entier turbo is spun on a VSR machine to 50k+ RPMS depending on the turbo to balance the entire thing. The VSR also test oil consumption at shaft speed to verify the bearing is working properly.

 

Thank you. Although I am fairly confident that any good turbo manufacturer (like Garrett) takes same steps to ensure quality.

 

I'm sure they do but I can't say what Garrett does since I've never seen how they make the turbos. I've watched turbo assembly at Turbonetics from start to finish which is why I can comment on that...

 

Oh, OK. Someone on this forum with an APS ST had the insid of his i/c covered in oil. Is that what you were referring to?

 

No that appears to be a design flaw with the turbo system not the turbo itself. What I meant was I know thats how Turbonetics produces turbos to ensure customers get a functioning, quality turbo every time. While I'm sure Garrett, Borg-Warner, Presicion, Innovative, etc, etc all do the same I can't say they do for sure. I've seen Turbonetics do it for every turbo they put together while I was in the assembly room and that one of their advertisements. I'm not sure if mass produced turbos are done the same is all I'm saying. Like I said with a well-designed kit, a quality turbo, and proper upkeep your turbo will last as long as your car does.

 

Did anyone with the APS TT ever have that?

 

People with the APS TT have had smoking issues due to apprantely improper draining of the oil from turbo's bearings....

 

Is that what caused that, I thought it was the oil level. I thought everyone was overfilling the engine with oil causing the oil pickup to pull too much oil or something. Im not sure tho...

 

Last I heard APS claimed it was the oil return line being too long and causing oil to back up in the bearings.