What does a bypass valve do and how does it work?

When I installed my novi 2000, the supplied hose for the bypass valve didn't reach to the vacuum tree. Since I was eager to hear the blower I started the car up without the line connected. It started up and the idle was up and down but figured I needed to mess with the MAM position. I drove it around the neighborhood for awhile. I then got a long enough vacuum line, and connected that along with my boost gauge to the vacuum tree. When I started the car, it ran like crap. Stalling out, running almost like it had a big cam in it. Any ideas as to why that happened?

Thanks,
Brandon

A bypass valve vents air when you have the throttle body blade closed so that the air being forced from the blower has somewhere to go. So basically the air that goes into the bypass valve gets recirculated back before the blower inlet. You need a vacuum line on the bypass valve. If the car is surging and running like crap you have a vacuum leak. You need to go over the line you plugged into the bypass valve if that is the only thing you've changed.