Note: This product is designed for use with Top Mounted Intercoolers. 2002-2005 WRX models will require removal of the cruise control module for proper fitment

The PERRIN Air/Oil Separator traps oil from the crank case vents before it enters the intake, thus increasing intercooler efficiency and reduces chances of performance-robbing detonation.

This Is Not A Catch Can

The PERRIN Air Oil Separator is not a catch can. Catch cans capture engine blow-by and stores it in a container, which requires constant attention and removal of oil every few hundred miles. The air-oil separator separates the oil from the air, draining it back to the engine, which eliminates the need for constant attention and draining of oil. As oil drains from the bottom of the PERRIN Air Oil Separator, clean oil-free air vents out of the top to rejoin the intake tract.

Swirl Pot Technology

Featuring swirl pot type technology and multi-layer baffles, the PERRIN Performance Air Oil Separator forces incoming air to circulate across the baffles, separating oil from engine blowby.

Custom Drain Back Fitting

Instead of using a universal type fitting, we have designed a purpose-built crank case fitting that does the job perfectly. Like the air oil separator body, the drain fitting is threaded to accept virtually any kind of fitting to allow for easy customization on special projects.

Heated By Coolant

The base plate of the air oil separator is heated by coolant drawn from the engine. This heats the entire air oil separator to the same temperature of the engine blow-by. By keeping the air oil separator the same temperature as the blow-by, water condensation is significantly decreased, allowing oil, air, and water vapor to separate and pass through the body.

Increase Intercooler Efficiency

The PERRIN Air Oil Separator increases intercooler efficiency by reducing the amount of oil deposited into your intercooler and intake system! As blow-by/oil builds up inside your intercooler, the less efficient it becomes due to less heat being transferred away from your engine. This leads to power loss and detonation, which can be damaging to your engine.

Reduce Carbon Buildup

Reduce carbon build up in the combustion chamber, intake valves, and in your intake tract. Crank case blow-by is recirculated back to the intake to be ingested by the engine, but in doing so, gets stuck in the intake tract, intake valves, and the intercooler. This builds up over time which causes a loss in power and extra wear and tear on your valves.

CNC Machined Fittings

The low-profile aluminum fittings provided with the PERRIN Air Oil Separator are CNC machined and anodized black for both a clean, sleek look and corrosion resistance. These tough and durable fittings are designed and finished to last the life of your vehicle.

Finish

Powder-coated for protection against the elements, the textured finish will look awesome for years to come. The PERRIN AOS is available in black or red texture powder coating.

Subaru Specific

Subaru engines have 3 main crank case vents located on each valve cover, and one in the center crank case. The PERRIN AOS is designed to connect to each of these separately without requiring any T connections. This allows for better venting and reduces the chance of oil being ingested during high G corners (common issue on flat type or boxer engines)