turbo noise followed by smoke?

[supraman666]

was driving my car went to pass a car started to boost it made a weird metal scraping noise i let off gas and as soon as the cars rpm droped a puff of smoke came out from behind the car. it runs and makes boost smooth no smoke under full throttle just a little cloud when the rpm drops like when the transmisson lets out of gear to coast (its an auto) do i have a bad turbo? can anyone give me some advice with my problem. any input would be helpful:1zhelp:

 

[easternguy2005]

Before my turbo went it would blow smoke when i let off the gas.

Warm, give it a little rev (~3.5 K). Let it come back to idle, then give it a little rev again and look for blue smoke. It only gets worse, and it boosted fine for weeks till I replaced.

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[supraman666]

sounds just like what is happening here. thanks