IAG Street Series Air/Oil Separator (AOS) 2015+ Subaru WRX

  • The IAG Performance Street Series billet aluminum Air/Oil separator (AOS) vents crankcase gasses back to the turbo inlet. The design is based on years of service on racing and high horsepower Subaru's. The AOS's approximate 1-liter capacity, fully heated housing, superior breathing and unique patent pending baffle design sets it apart from the rest.

    Why use an Air/Oil Separator instead of a catch can? Unmodified Subarus may require catch can draining as often as every few weeks. Heavily modified race cars may be as often as every race. 

    The IAG Air/Oil Separator (AOS) collects oil and actively drains the oil to the crankcase. The drain port is under the same crankcase pressure as the other ports that are on the side of the AOS. Under normal, off boost driving the weight of the collected oil will easily overcome the pressure in the drain line. However, under heavy boost (especially on higher powered engines) the crank pressure will push back up the drain with the same air/oil mixture that is seen on the side ports. The unique snail design allows the system to breath without disturbing the swirl pattern.

    The side of the AOS features three port billet hose barbs. There are NO plastic fittings that require thread tape to seal. 

    The Subaru FA engine has two ports at the top of the block that vent crank pressure. Each engine vent port receives its own connection to the AOS. Giving each engine port its own entrance to the AOS allows 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 liter of holding capacity. The larger the AOS, the more power you can safely make without having to worry about the AOS overfilling. 

    The AOS drain port is able to be rotated for ease of installation. All fittings supplied with the AOS are anodized aluminum and feature Viton sealed ORB fittings. The supplied coolant hose is built to SAE 20R3 standards. It will withstand coolant temperatures of +257°F. The oil vapor hose is designed to withstand oil and fuel vapors, exceeding SAE J30R7 standards. 

    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. 

    The IAG Street Series Air Oil Separator is not compatible with most aftermarket strut tower bars.

    Fits all 2015+ Subaru WRX. Includes a bracket to relocated the ECU forward on 2015-2017 cars.


  • SKU#: 10915SERE, 10915SEJE

    Shipping Weight: 7.0 lb

    Manufacturer: IAG

    Category: Engine Miscellaneous