BlackS/C

I didn't know we could use boost controllers.

Jmc007

Inside the supercharger, there is a "tunnel" that connect the inside port of the blower and the outside port. The by-pass valve (mechanical butterfly) is located in this "tunnel" and is activated by a vacuum motor (located outside the supercharger).

Here is an example of the manual boost controller set to 15 PSI with a 2.9" pulley or smaller :

When accelerating quickly, the supercharger forces the air in the manifold pressure quickly UP to 15 PSI, and try to force even more air. But at this 15 PSI, there is enough pressure to overcome the manual boost controller spring. So the air pass through the manual boost controller and let the supercharger internal by-pass valve opens slightly. If it opens too much, the manifold pressure goes down slightly under 15 PSI. At this point, the manual boost controller spring close, and manifold pressure goes back to 15 PSI. And up and down like this. BUT in fact, the pressure stays even at 15 PSI, it acts like a closed loop system.

Works very fine !