IAG Performance V3 Street Series Air / Oil Separator (AOS) 2015-2021 WRX

Fitment Info:

2015-2021 WRX

2014-2018 Forester XT

The IAG Air / Oil Separator (AOS) is a precision-engineered upgrade for your Subaru, designed to provide unmatched protection for 2015–2021 WRX and 2014–2018 Forester XT 2.0L FA engines. Developed through years of rigorous testing on both standard and competitive applications, the IAG AOS enhances crankcase ventilation and prevents oil from entering the intake, safeguarding your engine from premature wear, detonation, and performance loss.

At the heart of the design is a 1-liter cast aluminum swirl pot canister, featuring an intelligent baffle system that separates oil from PCV gases before safely returning it to the crankcase. Unlike traditional catch cans, the IAG AOS requires no routine draining—the oil gradually collects along the canister walls and drains back into the engine, while a proprietary heating system prevents condensation and sludge buildup.

The IAG AOS integrates seamlessly with the OEM PCV system, retaining intake manifold vacuum benefits while increasing capacity. In ethanol-fueled applications, it prevents oil dilution by capturing fuel vapors and reintroducing them for combustion. Lightweight yet durable, the aluminum housing reduces overall weight compared to previous designs, making it ideal for both street and track use.

Installation is simple with the included custom-length SAE Quick Connection lines, ensuring a secure, leak-free fit. Once installed, the IAG AOS delivers a polished, factory-like appearance that complements your Subaru’s engine bay.

Features: 

• True 360 Degree Rotating Breather Port

• Dual Breather Ports

• Greater Pressure Stream Oil Separation

• Compact Cast Aluminum Design

• Approximate 1 Liter Holding Capacity

• Aluminum Body is finished in powdercoat

• Unique Baffling Controls Crankcase Pressure

• Returns Oil To The Engine

• No Maintenance or Manual Draining Required

• Includes all fitting required for installation

• Includes unique billet aluminum coolant swivel fittings