IAG Performance Air Oil Separator AOS – Neon Yellow – 2015-2021 Subaru WRX / 2014-2018 Forester XT

IAG Air Oil Separator AOS — Neon Yellow — 2015-2021 Subaru WRX / 2014-2018 Forester XT

Keep Oil Out of Your Intake
The IAG Air Oil Separator (AOS) is a smart investment to protect and improve your 2015-2021 Subaru WRX or 2014-2018 Forester XT. Developed over years of rigorous testing on standard and competitive applications, the IAG AOS uses a 1-liter cast aluminum swirl pot canister to significantly improve oil separation from the PCV system before returning PCV gases to the intake. The aluminum housing provides improved ventilation and incorporates IAG’s intelligent baffle design. Works with all fuel types, prolongs engine lifespan, enhances crankcase ventilation, and integrates seamlessly with standard ECU settings. Available in Neon Yellow.

DETAILS

• Color: Neon Yellow
• Material: Cast aluminum swirl pot canister — 1 liter capacity
• Designed for 2015-2021 Subaru WRX and 2014-2018 Forester XT
• Prevents oil from coating intake components, intercooler, and boost piping
• Compatible with all fuel types including E85
• No tune required — works with standard ECU settings
• Package includes: AOS canister, hose and fitting kit, mounting bracket
• Part number base: IAG-ENG-7187

How the IAG AOS Works
Oil in the intake tract leads to problems that compound over time. Oil coating the intercooler core reduces heat transfer efficiency. Oil on silicone couplers degrades the rubber over thousands of miles. Oil that makes it into the combustion chamber contributes to detonation under boost. The IAG AOS intercepts crankcase blow-by vapors before they reach the intake — the 1-liter cast aluminum swirl pot canister creates enough volume and turbulence to separate the oil from the PCV gases before those gases are returned to the intake. It works with all fuel types including E85, does not require ECU changes, and includes the hose and fitting kit plus mounting bracket for a complete installation.

Easy Installation
The IAG AOS installs using the included application-specific hose and fitting kit and mounting bracket. No permanent modifications are required to the engine or intake system, and the AOS is designed to work with both OEM and standard ECU settings — no tune changes needed. Installation typically takes 1-2 hours with basic hand tools.

Why Color Variants Exist
All three variants — Black, Red, and Neon Yellow — are identical in function, materials, and design. The color is purely an aesthetic choice for your engine bay.

Why Choose IAG Performance

IAG Performance has been building Subaru-specific engine and drivetrain components since 2001, and in that time they have become the standard by which serious Subaru builds are measured. Based in Westminster, Maryland, IAG designs, machines, and assembles their products in-house using Haas CNC equipment and their own engineering team. Their catalog spans everything from short blocks and long blocks rated to 1150 BHP all the way down to the fuel system, oiling, and drivetrain hardware that keeps modified Subarus running reliably for years. Every IAG product exists because a problem needed a better solution than what was available — and the engineering shows.

The RallySport Take

The IAG AOS is one of the first modifications we recommend for any modified Subaru, especially turbocharged cars on E85 or running aggressive boost. The engine protection benefit is real and the installation is straightforward. IAG has been refining this design for years and the V4 is the most polished version yet — it is a well-sorted product that does exactly what it claims. If you are running a modified WRX or STI and do not have an AOS, this is the upgrade to do next.

Fitment