I have a T3/T4 Turbonetics turbo on my tC. It comes with a Raptor BOV and it makes a flutter sound when the air is released which is not what I wanted! I want the hiss sound so I tried 2 other BOV such as a Greddy Type RS and the RFL BOV which from what I've heard on other vehicles is a loud ___ hiss. Well on mine I get nothing but the flutter sound. I was told by turbonetics to check for any vacuum leakes and I have nothing. Any ideas, I'd love to hear them! Thanks

 

i have the greddy type rs and it makes a swoosh sound, like a looud sneeze

 

I think Turbonetics is right on the money.. that sounds like a vacuum leak.. I had the Turbonetics Raptor on my old tC and it sounded great and did not flutter. On an old turbo'd car, I had a vacuum leak and it fluttered like crazy .. Just check all your connections carefully