Turbo Whining

[mrplayer47]

So I'm not exactly sure whats going on but on my brothers and my friends wrx they are both making a loud whining noise when boosting. It almost sounds like its supercharged its weird, but basically, both of them put a Blow off valve on and then this started happening, except for on my brothers it did not make this noise until just recently but on my friends who has an APS 50/50 Blow off valve, his has been doing it since we put it and we have adjusted it up and down but it still hasn't changed so I'm not exactly sure what is going on, doesn't seem to be losing any boost or power, so if anyone has any ideas it would be muchly appreciated thank you!

[Anub1s]

My first thought was the spring in the blow off valves could be wrong. It's a good idea to stay with the stock one until it's actually needed to be upgraded anyways. I live on the SLC area, could look at it for you sometime, see if I could offer up some help.