The BOV needs to be connected to a vac. source correct?

 

Yes

 

I know this needs to me done but why??? What does the vac line have to do with bov activation? Went back to the stock bosch unit with cai but now the car boggs when I give it heavy throttle. any ideas why??

 

When under boost the vacuum line is no longer vacuu, but boost. The boost presure keeps the BOV piston from opening. When you come down of the boost and the presure drops back down to vacuum on the back side of the BOV the presure in the charge pipe will force the excess presure thru the BOV.

Kinda long but I hope that helps you understand a little more.