it sounds like seal problem... unless........are you still running the line from the inlet manifold to the three 5-6mm tails at the end of the blower ( sticking out of the end bearing / gear housings ) ???? These are there to equalize the pressures / vacuum in the blower and the bearing housings...otherwise it will suck oil from the housing into the blower under vac conditions and try to blow it out of the housing under boost.
regards, kevin