This maximizes the evaporation of any water collecting inside of the can. The back plate of the AOS features a unique coolant routing system that heats the entire AOS to the same temperature of the engine. Allowing maximum oil drainage while separating oil from the air in all the venting ports. 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. The larger the AOS, the more power you can safely make without having to worry about the AOS overfilling. With a 4' OD and 5.75' height, the AOS has an approximate 1 liter of holding capacity.

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

Heat Shielding on Crankcase Breather and Oil Return Lines.Compact Cast Aluminum Body w/ Black Powdercoat Finish.The COBB Air Oil Separator has been developed in partnership with IAG Performance and offers exclusive features. The COBB Air/Oil Separator is placed within your Subarus crankcase ventilation system and helps to prevent oil vapors from being introduced into the intake system.

Aig air oil separator review