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IBR Air Oil Separator 2002-2007 WRX / 2004-2021 STI

Original price $299.99 - Original price $299.99
Original price
$299.99 - $299.99
Current price $299.99
Select Version: Drive by Wire


This kit is designed to be the best AOS on the market. It is a triple pass system with carefully designed diameters and cross sections to effectively remove a range of oil droplet sizes. This AOS installs directly above the main crank case vent between the intake manifold and the TMIC. Installing here allows a clean look and the shortest possible hose routing. Since this is a true AOS the oil drains back into the block and never needs to be emptied. Small ridges on the faces of the spiral baffles collect the oil and allows the oil to stay out of the laminar airflow and effectively drain down to base of the system. The internals can be cleaned periodically by disassembling the unit with the tool-free thumb screw on top.


Drive by Wire:
2004 - 2021 STi
2006 - 2007 WRX (2008 - 2014 WRX can work if updated to the STi intake manifold)
2004 - 2008 Forester XT

Drive by Cable:
2002 - 2004 WRX

Works with a lot of of other vehicles with EJ20/25 engine swaps that utilize the OEM STi or WRX aluminum intake manifolds.

Key Benefits:

  • Never needs to be emptied

  • Short hose routings for a very clean install

  • Carbon fiber outer housing tube for a high performance look and feel

  • Retains factory PCV functionality

  • Triple pass system for the most effective droplet separation

  • Tool free and easy to clean assembly

Included in the kit:

AOS01 Assembly
AOS01 Mounting Bracket
All Required Hoses and Hose Clamps

This product will not ship to California. It is not CARB approved. We do not feel that this product alters or changes the emissions systems on the car but due to the California regulations we cannot currently ship to that state.