Take the intake pipe off the turbo and check for excessive shaft play, oil leaking and rubbing between the comp wheel and the housing. Also remove the oil drain line from the pan, crank it up and see if oil drains out of the turbo, might have a restricted orifice.

 

Did you do any work right before this noise started? It sounds like an intake leak. Any loose clamps or holes on the intake side? Start with the simple stuff

 

i want to make sure this isn't just typical turbo spool whistle.... does it sound like a whilstle? adding an aftermarket intake will allow you to hear the turbo and BOV mucccchhhhh louder.