Alright, I did a little looking around (actually I'm just trying to hit 100 posts and needed something to post

), and Demon, I think you're wrong. Every single place I looked listed the use of a blowoff valve as controlling compressor surge, and a bypass valve doing the same thing. They're also called surge valves, hooter valves, shift valves, relief valves or dump valves.
Straight from Greddy's website: "Our Blow Off Valves are easily adjustable to prevent both premature boost leakage and compressor surge." I think I'll believe what Greddy says more quickly than what you can say. No offense, you're usually a wealth of information, but they have a little more experience with turbos.
Bob
P.S. I'm up to 93 posts.