My car is mostly an FM kit, GT2560, MS3 PNP, standard stuff. Been driving it for several years, no issues. I R=recently upgraded to 640cc injectors from FlowForce. Changed settings on MS to suit new injectors, car runs reasonably well. A few days later, I did some idle tuning in my driveway, car ran for 30-40 minutes, again normal, fan works as expected so no heat issues or anything. The car sat outside for several days after that. Went to start it up yesterday and there is a strange... humming? whirring? something? noise coming from the intake. Sounds loudest right at the air filter. Started car today, same sound. The sound does not change with revving the engine. Obviously gets drowned out some, but the frequency and volume seem to stay the same, which is the really strange part. I would expect a compressor-related sound to change in pitch with RPM, at least somewhat. There seems to have been no impact on performance. I removed the air filter briefly, no change to the sound.

I uploaded a video to youtube, hoping someone will take a listen and recognize the sound or at least have a theory on what it is.

Video on youtube:

 

Could be your iacv, my hums differently depending on the frequency it’s set to. I think you can go into the calibration wizard and turn it off to see if the noise stops to verify