IAG Air / Oil Separator (AOS) For 2015-21 Subaru Impreza WRX

The IAG Performance V3 Street Series Air/Oil Separator (AOS) is a valuable investment in maintaining optimal performance for your Subaru. The design of the Street Series AOS is the result of years of thorough testing on both standard and competition applications. This AOS consists of a 1-liter, cast aluminum swirl pot canister, which more effectively separates oil from the PCV system upstream of PCV gasses’ return to the intake system. The Street Series AOS has a heated aluminum housing, excellent venting, and it features a one-of-a-kind baffle design that stands out from the competition. The Street Series AOS works with all fuel types, prolongs engine life, enhances crankcase ventilation, and fits with standard ECU settings.

Preventing oil from entering the engine intake tract is crucial for avoiding premature mechanical issues and sustaining optimal performance. Oil present in the engine's intake tract has various negative impacts; Initially, it coats the internal components of the intake, intercooler, and piping. This can cause potential damage or premature failure of rubber or silicone hoses, and eventually, failed connections. Once the oil makes its way to the intake tract, it directly enters the intake manifold and subsequently enters the engine's combustion chamber. Once inside the chamber, the oil can cause detonation, pre-ignition, high emissions, smoke, loss of power, decreased gas mileage and even severe engine damage or complete engine failure.

The IAG AOS is engineered to require zero maintenance. Unlike standard catch-can systems, our Air Oil Separators do not not require regular draining and maintenance. Oil that has been separated collects on the AOS can walls and slowly drains back into the engine's crankcase by gravity. The collected oil remains free of sludge with the help of our unique heating system, ensuring that there is no risk in reintroducing it into the engine. The large volume of the AOS body provides sufficient time for oil to drain back safely, eliminating the risk of overflowing seen in smaller catch cans.

The IAG Air Oil Separator has a distinctive baffle system designed to gather the oil suspended in your engine's PCV gasses, and allow it to drain back into the crankcase. The inlet hoses on the AOS body are positioned so that they create a vortex of the gasses inside, which are then filtered through a series of baffles. The baffles work to collect the oil, while allowing the gasses to escape from the top of the AOS canister. Since the factory PCV is still functional, the engine also creates a vacuum on the AOS assembly to further draw out the PCV gasses.

The Street Series AOS not only maintains the OEM PCV system functionality, but boosts its capacity. The Street Series AOS redirects PCV discharge gasses back to the turbo inlet, using the factory PCV valve for additional suction and improved air-oil separation. In ethanol-fueled applications, the Street Series AOS safeguards against oil dilution and lubrication issues. This is achieved by capturing fuel vapors from the oil and reintroducing them into the intake tract for combustion. The Street Series AOS offers superior protection against oil getting into the intake flow and oil dilution in the engine's lubrication system, surpassing the capabilities of the OEM PCV system alone.

The IAG Street Series Air Oil Separator uses a special heating system to address issues found in inferior catch cans. In other versions, the hot PCV gasses travel through a cold passageway, which creates condensation. Over time, this condensation mixes with the oil in the system, causing sludge. IAG’s Street Series AOS is designed to attach to the vehicle’s cooling system, allowing heat from the engine to transfer into the AOS canister. By heating the AOS canister to the same temperature as the engine, the condensation and related buildup is significantly reduced or eliminated.

For the 2015-21 Subaru WRX our engineers set out to make the system as easy to install as possible. The connection hoses are measured out and arrive pre-cut to the exact length to reach the corresponding engine parts. The AOS is available in your choice of three colors to accent the engine bay of your Subaru.