[A418t81]

Possibly, but I doubt it. Non-ball bearing turbos such as our stock units use a hydrodynamic bearing. That is, the center shaft actually floats on a cushion of oil and doesn't really touch anything other than the thrust washer which takes the axial loading of the shaft and wheels (the compressor trying to come forward, out of the compressor housing). There are lots of turbos that have some whine when the oil is cold and I think it is related to the oil viscosity. The cold oil "sludges" a bit on the shaft as it's spinning and causes some humming which resolves once it has enough heat in it to be slung off rather than adhere. Another thing to remember is that little tiny turbos like ours turn INSANE rpm to make even stock boost. Probably 150,000 rpm just to get to 7 psi. It probably doesn't make any boost until around 100k rpm. It doesn't take much at all at those speeds to have a hum