Guys,
Where does the whipple get its vacuum reference to open/close the bypass actuator? Looking at my blower i see the actuator vacuum line runnung from the actuator up to the back of the blower housing but thats it. It never taps in to the engine vacumm anywhere. Here is a picture......

 

You have to think of the blower as part of the intake, or part of the engine. That is your engine vacuum. That is the only place on your engine that only ever sees vacuum. If you ran the line from the intake manifold, the actuator would see boost, and possibly be damaged.

 

I figured i was over thinking it. Thanks Mike.

 

between throttle body and SC goes from vacuum to atmospheric
between the SC and manifold goes from Vacuum to Boost