IAG Performance Air Oil Separator AOS – Red – 2008-2014 WRX / 2008-2021 STI / 2005-2009 Legacy GT

IAG Air Oil Separator AOS — Red — 2008-2014 WRX / 2008-2021 STI / 2005-2009 Legacy GT

Keep Oil Out of Your Intake
The IAG Air Oil Separator (AOS) provides exceptional engine protection for the 2008-2014 Subaru WRX, 2008-2021 STI, and 2005-2009 Legacy GT. Developed over years of testing on standard and competitive applications, the IAG AOS uses a 1-liter cast aluminum swirl pot canister to dramatically improve oil separation from the PCV system before returning PCV gases to the intake. The aluminum housing features IAG’s intelligent baffle design that separates it from competing AOS options. Works with all fuel types, extends engine life, improves crankcase ventilation, and integrates with standard ECU settings with no changes required. Available in Red.

DETAILS

• Color: Red
• Material: Cast aluminum swirl pot canister — 1 liter capacity
• Designed for 2008-2014 WRX / 2008-2021 STI / 2005-2009 Legacy GT
• SAE quick-connect hose and fitting kit included
• Prevents oil from entering intake, intercooler, and boost piping
• Compatible with all fuel types including E85
• No tune required — compatible with standard ECU settings
• Package includes: AOS canister, SAE quick-connect hose and fitting kit, mounting bracket
• Part number base: IAG-ENG-7186

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.

SAE Quick-Connect Fitting Kit
The 7186 uses IAG’s SAE quick-connect hose and fitting kit for a clean, secure connection to the PCV system without the need for barbed fittings and clamps. The quick-connect design simplifies installation and makes future service straightforward.

Why Color Variants Exist
All three color variants — Black, Red, and Neon Yellow — are identical in construction, materials, and performance. The color choice is purely cosmetic, allowing you to match your engine bay build.

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