[uiuc240]

Think of it by the way the controller works:

There is a spring in there holding a ceramic or steel ball over a hole. Once that ball moves, the pressure is released through the other side, and the wastegate opens. The more spring pressure you have, the harder it is for the ball to move. Therefore, by adding more spring pressure, you allow more boost to be created before the wastegate opens.

So, if you loosen the screw all the way out that holds the ball and spring in place, you will effectively eliminate that system (putting you at stock boost). The tighter you make it, the more boost you will create.

Make sense?

Eric