I know what they do they releave the presure in the turbo manifold to make less boost. but what i want to know it how they work. does it need a vacume to open like the bov,or does it just work off the preasure of the turbo manifold. and if not what the hell do i screw into the top and the side of it. I'm thinking that they are for a boost controler (which i don't have) so do i just leave them open. thanks for the help

 

im kinda confused on exactly what your trying to do.... pics possibly may help a bit.

the way i understand they work is basically the same way a manual boost controller does. There is a valve attached to a spring in which the rate is set to a certain positive PSI. Once your manifold reaches that PSI, the spring will begin to compress and allow the valve to open and release pressure until the pressure matches the rate of the spring again and the valve closes. Somebody correct me if im wrong, but i think thats it

 

It diverts exhaust gas from the turbine when it has reached the spring capacity by dropping the overall pressure of the manifold.

It runs off vacuum pressure. The best pressure source to get it from is right after the compressor housing, so you are seeing boost as it is made, not after it reaches the throttle body.

Leave those other two ports open. They are for a boost controller.