How does the bypass valve work? I know it relieves the boost when not needed?
What activates it though?
Mine has a spring pack that's adjustable through the addition or removal of shims. There's a "vacuum" line that connects the actuating piston, and coil spring, to the engine's intake system. When intake vacuum overrides the spring pressure in the bypass valve, it opens to let the compressed air escape into the atmosphere instead of keeping it bottled up behind the almost closed throttle butteflies. The signal it "sees" comes from downstream of the carb, not between the carb and turbo, so when there's not much load on the engine, there's a vacuum there. The supercharger doesn't know that, so it keeps making boost... gotta dump it somewhere.
If this is wrong, maybe someone can correct me, but that's the way I see it.
Thanks.