IAG Competition Series (AOS) Air/Oil Separator | Subaru Impreza WRX /STI (IAG-ENG-72)
IAG AOS 2002-2015 WRX / STI
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.
As air and particles of oil enter into the AOS, the largest particles of oil will collect on the inner surface of the can and drain to the bottom, but the smallest particles will remain suspended in the pressurized stream. As the air makes its way through the multi-stage baffle system, gravity pulls oil from the air. By increasing the diameter of the breather opening on the top of the AOS, we have drastically decreased the exit velocity of the crankcase vent (CCV) stream. The slower velocity leads to greater oil separation from the pressure stream. A total of 9 mounting holes give the breathing port a full 180° of rotation. On the bottom, a thick Viton o-ring seals the can. Every o-ring in our AOS is formed from Viton which offers superior temperature and chemical resistance.
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 they have 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 liter 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. Why not use a catch can? Unmodified Subaru's may require catch can draining as often as every few weeks. Heavily modified race cars may be as often as every race.
IAG's 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 supplied coolant hose is built to exceed SAE J20R3 standards. It will withstand coolant temperatures up to 300°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 center bracket allows for adjustable mounting. If your engine bay changes, you can easily change how and where you mount the AOS. A single laser cut mounting bracket is included that fits nearly all applications and configurations. A laser cut harness relocation bracket is also included. The bracket allows the engine harness connector to be moved forward for additional clearance.
IAG Performance AOS Features:
- Large Breather Port
- Greater Pressure Stream Oil Separation
- Large Billet Alumium Design
- Approximate 1 Liter Holding Capacity
- Integrated 3 Port Billet Hose Barbs
- Returns Oil To The Engine
- No Maintenance or Manual Draining Required
- Heated By Engine Coolant
IAG Air Oil Separator Benefits:
- Unique Baffling Controls Crankcase Pressure
- Reduces Moisture & Oil Mixing
- 180° Breather Port Rotation For Install Ease
- The IAG AOS is not compatible with most aftermarket strut tower bars
- 2006-2016 Subaru WRX
- 2004-16 Subaru STI
What's in the box?
- Hardware, Lines & Fittings Included
- Multi-point Adjustable Mounting Bracket
- Ready To Install