The second turbo sent turbine fragments back into the exhaust port and took out an apex seal.

This cost me a housing, a set of seals and a drive to North Carolina. 

 

Hi John,

 

How confident are you in this diagnosis?  Did you actually find pieces of turbine blade imbedded in the housing?  Did Bruce says he's seen this plenty of times before?  

 

I've got to admit that I have a hard time believing this could happen.  As Ed said, they're spinning fast, but the energy will be mostly centrifugal force, with some forward momentum thrown in.  When you think of the angle that the exhaust hits the turbine, it just seems really unlikely this could happen. 

 

I've always wondered if that failure didn't happen just the opposite.  If detonation broke an apex seal, it would go into the turbine.  This in fact happens all the time on the cars.  

 

Good luck with your new turbo.  

 

Rusty (new kits are soooooo nice)