When you have smoke coming out of the exhaust pipe It's because the oil is getting into the turbine not the compressor, the compressor has a seal the turbine only has what looks like a piston ring and doesn't seal oil only exhaust pressure from getting into the bearing housing. As Tom said the oil after the turbo is full of air and can hardly flow so it needs a constant drop to the oil pan or it will back up and run out the turbine and burn. Also put the drain at a main bearing cap location to help shield the drain from windage.
If you have any more than a trace of oil in the compressor you have a different problem and need to check out the turbo !
Harry
I know why you are in a hurry to drive the car, boost is addictive.
