oil leaks after turbo'd

If you feel that you are getting excess oil from you crankcase then the first place I would look is the condition of the rings. Try doing a compression test wet and dry. That will at least give you a idea if that is where it is coming from. If it comes out fine then check into the turbocharger. Im just not understanding how your air filter has been exposed to oil as it is before both the crankcase venilation and the turbo. But good luck and hope its nothing major.