What kind of answer are you looking for? lol. I mean theres only a few things that cause turbos to smoke.

1.. not running an oil restrictor on a turbo that needs one and shoving oil past the seals. - overhaul turbo and add oil restrictor.
2.. oil starvation and the rings wear out or the shaft gets scarred. usually has shaft play - overhaul turbo and fix oil source issue.
3.. oil doesnt drain well and backs up, blowing out the seals. - overhaul the turbo and fix the oil drain.
4.. wear and tear.. turbo develops shaft play and seals cant contain the oil any more. - overhaul turbo.

notice a trend?