jw kind of a stupid question, but can you get a bov if your car is supercharger?!? no huh?!?!

 

YAY! you can for the s2000! i'm so happy now

 

with a blower, the screws only spin as fast as the pullies will allow; the blower is driven via belts off of the crank, so there's a maximum speed the screws will spin and thus a maximum boost to be had. to change your max psi, change your pulley sizes...
so, no, there's no need for a BOV on a blown engine.