IBR Air Oil Separator - Subaru STi 2004-2021 / WRX 2002-2007 / FXT 2004-2008
IBR Air Oil Separator - Subaru STi 2004-2021 / WRX 2002-2007 / FXT 2004-2008
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IBR Air Oil Separator - Subaru STi 2004-2021 / WRX 2002-2007 / FXT 2004-2008

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IBR Air Oil Separator - Subaru STi 2004-2021 / WRX 2002-2007 / FXT 2004-2008

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.

2004 - 2021 STi
2002 - 2007 WRX (2008 - 2014 WRX can work if updated to the STi intake manifold)
2004 - 2008 Forester XT

Works with a lot 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.

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Returns Policy

Returns may be accepted within 14 days of purchase pending Return Merchandise Authorization (RMA). No returns or cancellations on special order items. All returns will be charged a 20% restocking fee, no exceptions.

To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging. Item must be able to be resold as new. Several types of goods are exempt from being returned. Hazardous materials, fluids, greases, chemicals, and clothing are not able to return.

Free shipping is available within the lower 48 states for most orders totaling $199 or more. A free shipping option will be available during checkout. This offer is for delivery address in the continental United States and excludes shipments going to Alaska, Hawaii, Military Boxes, and items that require freight shipping.

Processing Time
Patterson Performance stocks a large quantity of items at any given time. Some items may require drop shipping from one of our various distributors. In stock items will ship within 1-2 business days. If you're needing your product quickly, please contact us to verify product availability before placing your order. Orders requiring additional verification (security concerns, incorrect information, etc.) may need additional processing time. Estimated shipping dates are not guaranteed and are subject to change based on inventory levels and manufacturer lead times. Backordered items are shipped immediately once available.

Items ship daily, If the item you ordered is not in stock, a member of our team will contact you via email / phone.

Patterson Performance will only ship to an address that varies from your billing address if payment is made via Paypal or a financing partner.

Patterson Performance ships from multiple warehouses throughout the United States, and sometimes from manufacturers overseas.

You can simply contact us via email / telephone for a live inventory check

P65 WARNING: Cancer and Reproductive Harm

Find more information at www.P65Warnings.ca.gov.

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