i'm about to set up my first intake. i've been told and have been reading around that certain and usually higher end CAI's can produce a harmonic and almost turbo-sounding whistle. does anybody know what it is that causes this in certain intakes or filters and if quiet intakes can be modified to make that sound?

 

most aftermarket intakes will make more noise than your stock one..its basically the filter on it that will change the pitch...

 

its how the air flows thru, thats what makes the noise.. whatever you do, dont buy one of those stupid turbo whistlers that you put on your exhaust..

(will post reference if you dont know what it is)

 

The plastic intake box you remove is technically a "silencer" for the intake. If you remove that, put on a bigger filter and piping, will hear the noise. Nothing wrong with it though.