Originally Posted by evo335xi
How much it is throwing off your air/fuel might be up to the size of the leak. Your turbo will be working harder no doubt, the question is how much. Look up whistling/siren noises after intercooler installs. They don't have to be Bmw specific either. I might be completely off but imo check it out.
I did this and found a FAQ on Garretts website:
Q. What is/causes Shaft Play?
A. Shaft play is caused by the bearings in the center section of the turbo wearing out over time. When a bearing is worn, shaft play, a side to side wiggling motion of the shaft occurs. This in turn causes the shaft to scrape against the inside of the turbo and often produces a high-pitched whine or whizzing noise. This is a potentially serious condition that can lead to internal damage or complete failure of the turbine wheel or the turbo itself.
Unfortunately this sounds like my issue besides the fact that mine only whines during full WOT and not at low rpms like the old n54 whining issues...
Assuming there is nothing I can do about it? Is best bet to go back to stock and make an appt with bmw? I ruined the stock intercooler piping (cut the metal clamp and went into the plastic piping itself. I think besides that and with some work, I can get her back to stock). Oh, and should i take downpipe off too? I'd have to have the shop do that