ok so we have an fc with an rew motor in it, BIG street port 3mm seals, engine is kinda tired. big front mount, e11 haltech, 1600cc secondaries. new o trim exhaust wheel in s5 exhaust housing, i think it was h trim compressor, but i'm not sure. it ran fine on the street, boost was stable at about 10psi.



we took it to the track, and it lasted 5 laps. half way thru lap 5 it stopped making boost (ie put foot on gas, guage goes to zero), when you give it gas it goes to zero and makes a funny noise(high pitched) so we pull into the pits and engine is blown too.



so drive 238miles home, turbo starts smoking badly. we pull turbo off, and the edges of the exhaust wheel are melted looking, and the shaft is broken off right at the bearing housing. compressor side is cherry.



i'm kinda thinking it was too hot in there (the last turbo did almost the same thing except the turbine exited the building). but why did the motor blow? just cause? or is this related.



mike

sounds to me as if your exhaust backpressure was too high-



It had to be damn near stratospheric to melt the turbine wheel.

Aren't they usually made of inconel?

too lean with too retarded timing maps?

if anything its too much timing, 20degrees@10psi and afr in the 11's?

exhaust temps?

Did you have to machine the exhaust housing for the O trim wheel? If the wheel was hitting the housing it could have caused the problem. Once the wheel sheared and stopped moving it created alot of back pressure and heat that could have blown the motor. Are you using atkins apex's (can't take excessive heat)? Do you have any exhaust temp readings?



The high pitched squeal/screech is usually the exhaust wheel rubbing on the exhaust housing.

that sucks



atleast some good ideas so far

yeah you do have to machine the housing a little, it looks cherry. no egt guage, and its got mazda 3mm seals in it

That sucks! You got any pics?