Cobb 08-14 Subaru WRX / 08-20 STI Air Oil Separator

The COBB Subaru Air/Oil Separator prevents crankcase oil vapors from re-entering the engine's intake, which can lower fuel octane and contribute to carbon buildup. Developed with IAG Performance, it features a 1-liter capacity, integrated ORB ports, and a compact cast aluminum body with a black powder-coated finish. It includes heat shielding on crankcase breather and oil return lines, a coolant bleeder valve, and a bespoke COBB color with a laser-etched logo. Designed for the Subaru EJ engine, it connects to three crank pressure vents (one on each cylinder head, one on top of the block) for efficient pressure excavation. Its snail-shaped bottom redirects crank pressure into a swirl pattern for maximum oil drainage. A unique coolant routing system on the backplate heats the AOS to engine temperature to maximize water evaporation. CARB Approved (EO number: D-660-25D-660-45).