[Unreal]

BOV protects the blower. It releases excess air when you let off the throttle. When the throttle closes there is no where for the air to go which backs up in the blower causing surge and beating on the blower bearings/etc. A BOV releases the air to atmosphere. The ECS kit comes with a BOV. A wastegate (or even a BOV without a vacuum/boost line hooked up) can be used to bleed off excess pressure in a centri blower setup. You could pulley for ~15psi, then set the wastegate to bleed off any pressure of 10psi, and if you were at sealevel or 6000 ft you would get 10psi. Wastegate would only let you go down so if you pulley for 12 and at elevation only make 9psi, and have WG at 10, then you would still only get 9psi at elevation and 10 at sealevel. WG can be tricky to get working good on a blower car. Too big or too small it hard to setup, spring sizes, etc. They were made to bleed off exhaust gas for turbos not centris. I've seen people get crazy roller coaster boost curves where the gate dumps a bunch, then closes, then dumps a bunch.