The IAG Air/Oil Separator (AOS) is a smart investment to safeguard and improve your Subaru's performance. Developed over years of rigorous testing on various standard and competitive applications, the IAG AOS provides unmatched protection for your 2015-2021 Impreza WRX engine. Our exclusive AOS design incorporates a 1-liter cast aluminum swirl pot canister that significantly improves oil separation from the PCV system before returning PCV gasses to the intake. The durable and lightweight aluminum housing provides improved ventilation, while incorporating the use of an intelligent baffle design that sets it apart from the competition. It works with all fuel types, prolongs engine lifespan, enhances crankcase ventilation, and seamlessly integrates with standard ECU settings.

Oil in the engine's intake tract may lead to various negative effects. Preventing oil from entering the engine intake is vital to prevent premature mechanical issues and to uphold optimal performance in your Subaru. Oil coated components in the intake, intercooler and plumbing can lead to the breakdown of the rubber and silicone hose connections. Once the oil enters the intake tract, the oil can access the intake manifold and then the engine’s combustion chamber, potentially triggering detonation, pre-ignition, excessive emissions, smoke, power loss, reduced fuel efficiency, and even engine damage or complete engine failure.

Unlike ordinary catch-can systems, the IAG Air/Oil Separator functions without the need for routine draining or maintenance. The separated oil gathers along the walls of the AOS canister, then drains gradually into the engine's crankcase. The large body of the IAG AOS eliminates the risk of overflow by allowing the oil to drain slowly, whereas smaller catch cans are unable to keep up and often require manual draining. The exclusive heating system on the IAG AOS ensures that the gathered oil remains free of sludge, reducing the possibility of reintroducing it back into the engine.

The IAG Air Oil Separator uses a unique baffle system to collect and drain the oil from your engine's PCV gasses back to the crankcase. The AOS body's inlet hoses create an internal gas vortex, which then filters through the baffles, trapping the oil and allowing the gas to escape from the top of the AOS canister. Because the OEM PCV remains functional, the engine is also able to provide additional vacuum, which helps to remove more of the PCV gasses.

The IAG Air Oil Separator works alongside the OEM PCV system, while increasing its capacity. It assists the PCV gasses to the turbo inlet using a new, upgraded metal PCV check valve that provides extra suction and air-oil separation. In ethanol-fueled applications, it prevents oil dilution and lubrication issues by capturing fuel vapors from the oil and reintroducing them for combustion. IAG’s AOS prevents oil from entering the intake and oil dilution in the engine's lubrication system, going beyond the capabilities of the OEM PCV system alone.

Crafted with a lightweight yet sturdy aluminum housing, the IAG Air Oil Separator is even lighter than our previous AOS iterations. Whether you're drag racing or hitting the track in your Subaru, we value the importance of weight savings. This is why we've fine-tuned and lightened this AOS design to enhance your Subaru's overall performance, guaranteeing you get the best results every time you race or hit the track.

The IAG Air Oil Separator features a proprietary heating system that capably handles issues frequently encountered in lower-quality catch cans. Unlike inferior designs that allow hot PCV gasses to pass through cold passages, leading to condensation mixing with oil and causing sludge, IAG's improved design is linked to the vehicle's cooling system. This enables the transfer of heat from the engine into the AOS canister. By heating the AOS canister to the engine's temperature, condensation and associated buildup are significantly diminished or completely eliminated.

IAG's Air Oil Separator comes with a complete set of custom-length SAE Quick Connection lines, simplifying the installation process and minimizing the risk of leakage as a result of a more dependable and secure connection compared to standard hose clamps. Once installed, our AOS system features a polished factory-like appearance that matches your Subaru’s engine.

Our engineers set out to make the system as easy to install as possible for the 2015-2021 Impreza WRX. The connection hoses at the canister are custom fitted SAE Quick Connection lines that are the exact length to reach the corresponding engine parts. The IAG Air Oil Separator also includes pre-cut and crimped hoses on applicable Subaru models. The IAG AOS is available in your choice of black, red or neon yellow to perfectly accentuate the engine bay of your Subaru.