I finally installed the AccessECU stage 2 ECU reflash today and everything seems to running almost perfectly with the exception of what seems to be an unrelated problem.

The issue I'm seeing is actually something I first noticed when I first installed my uppipe/downpipe many months ago and tried using a MBC for a few days. I can hear a high pitched noise when under heavy acellearation and boosting over 15psi+ while in the upper range of the RPMs. The noise was never noticed again once I removed the MBC so I just didn't give it much thought at the time. The car has been driven running stock boost in all conditions with no symptons of any problems or leaks for many months. Once again now again now after the ECU reflash which raised the boost about 1-1.5psi over the stock readings on my boost gauge I can hear the noise. The car still seems to pull hard and the boost appears to be rock solid and everything seems to be healthy but it just doesn't sound right to me.

I really don't think it's an uppipe leak as that was much louder and higher pitched and fairly easy to track down. I did a visual re-inspection of the uppipe gaskets and downpipe today and I looked for any traces of leaks and I'm fairly certain at this point that there are no leaks in those locations. I checked the intercooler hoses(Samco) and everything is on nice and tight along with all of the vaccume lines appearing to be snug with no signs of any leaks or problems.

You guys have have any ideas on what could be causing this? Has anyone else notice a high pitched(not too loud but noticable) noise when raising boost a bit? Maybe it's wastegate noises at higher boost levels and everything is fine but my gut tells me otherwise.