#109720, "RE: Wastegate and Boost Pressure" In response to In response to 6
At least on my Type S, there is an upper and lower chamber on the BOV. If you connect to the wrong one, it will open as boost rises. If the RS only has one port, then I don't know. Maybe a ripped diaphragm? That would leak air pressure out of the upper chamber and not resist the force applied by boost on the other side of the valve. With a weak enough spring, boost in the piping could force the valve open.