With the solinoid disconnected your ECU wont be able to control when the wastegate opens. That means the you are relying on the spring inside the waste-gate to regulate the pressure. It limits your maximum boost to the strength of the spring and gives you no control over boost pressure.
For my money I wouldn't just trust the wastegate spring, You can get a solid BCS for around a hundred bucks, if it keeps the engine happy thats worth the money for me.
So,when I go to my tuner I can install my new Grimmspeed BCS in the parking lot (they charge $50) and just don't plug it in to drive it into the bay? I'm told don't drive it one inch with it hooked up without a tune. Is this true?
The sensation is as hard to forget as it is to ignore!!!