Cobb 06-07 Subaru WRX / 04-07 STi Air Oil Separator - 811615

The COBB Air/Oil Separator is placed within your Subarus crankcase ventilation system and helps to prevent oil vapours from being introduced into the intake system. The COBB Air Oil Separator has been developed in partnership with IAG Performance and offers exclusive features.

The Subaru EJ engine has 3 ports that vent crank pressure: one on each cylinder head and another on the top of the block. Each engine vent port receives its own connection to the AOS. By giving each engine port its own entrance to the AOS COBB has allowed for more effective and faster excavation of crankcase pressure.

Additionally, this reduces overall system pressure. With a 4" OD and 5.75" height, the AOS has an approximate 1 litre of holding capacity. The larger the AOS, the more power you can safely make without having to worry about the AOS overfilling.

The bottom of the AOS is shaped like a snail, redirecting positive crank pressure into the same swirl pattern produced by the 3 side ports. Allowing maximum oil drainage while separating oil from the air in all the venting ports.

The back plate of the AOS features a unique coolant routing system that heats the entire AOS to the same temperature of the engine. This maximizes the evaporation of any water collecting inside of the can. The hotter the AOS, the less water will collect inside and mix with the oil.

Why?

The COBB Subaru Air/Oil Separator helps to prevent crankcase oil vapours from recirculating back through your engine's intake system.

Oil vapours passing through your engine's intake system lower the effective octane rating of fuel and can contribute to both oil and carbon buildup over time.

Subaru Air/Oil Separator FXT 2004-2008, WRX 2002-2007, STI 2004-2007.

This AOS can be installed to 2002-2005 WRXs with modification to or relocation of the Cruise Control Module.