I was told i can raise and lower my boost with the controller..... But, looking at it.... you cannot adjust for less boost then your wg spring is set for correct? So if i have a 12psi spring, that is the lowest i can go?

 

if using a manual boost controller we start of using about a 2psi spring then using the manual boost controller creep the boost up with tuning ,, how ever at some point your pre turbine back pressure may start to push open that light of a spring

 

Correct. Wastegates are designed to regulate boost to the spring pressure while using a manifold pressure reference. If you remove this reference from the gate, the gate will stay shut until exhaust pressure becomes high enough to push the gate open. The purpose of a boost controller it to target some area in between there. If too light of a spring is used to the point where you want more boost than given by disconnecting the reference, that same reference can be swapped to the other port on the gate to help keep it closed. In this case the controller would be used to target lower boost than would otherwise happen.