AVO utilizes the latest technology in lightweight internal piston valving to ensure optimum blow-off response at all times. The design of the V3 BOV has been updated with new internals to better manage compressor surge. AVO blow-off valves are a 50% recirculate, 50% vent system that retains the return tube, keeping the stock computer system happy, while an additional vent with removable plate sends hot air to atmosphere if you choose.