Zawór blow off BOV Turbosmart TS-0203-1015 Kompact Dual Port Subaru Forester XT WRX STI - TS-0203-1015 - Dual outlet-type BOV. The Kompact Dual Port vents both to the atmosphere and back into the air intake. Ports with sequential timing allow quieter operation during normal driving, while still offering the performance and sound of a vent-to-atmosphere BOV when the going gets harder. The standard blow-off valves on these cars are made of plastic, unlike the highly durable machined billet construction of the Kompact. The standard valves are often not up to the task of eliminating damaging compressor surge, and as the cars age, the plastic becomes brittle and can crack, causing severe boost leaks. This prevents the turbo from reaching its full potential, robbing you of performance. With its anodised billet aluminium body and lightweight alloy piston, the Kompact offers extreme durability, superior response and excellent boost holding capability for its size. The Kompact Dual Port is perfect for owners of stock to lightly-modified cars looking for the classic vent-to-atmosphere BOV sound in an OEM-replacement, space efficient package.