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Perrin Performance

Perrin - Subaru 08-14 WRX/STI - Air Oil Separator (Red)

Perrin - Subaru 08-14 WRX/STI - Air Oil Separator (Red)


Regular price $572.00 USD
Regular price $545.00 USD Sale price $572.00 USD
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The PERRIN Air Oil Separator traps oil from the crankcase vents before it enters the intake, reduces carbon build-up, increases intercooler efficiency, which reduces the chance of performance-robbing detonation.


Increase horsepower and torque without ECU recalibration or tune! This part is designed and tested to work safely on your vehicle without any tuning required! However, more power can be gained with proper ECU tuning!


The PERRIN Air Oil Separator is not a catch can. Catch cans capture engine blow-by and store 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.


The PERRIN Air Oil Separator features swirl pot technology and multi-layer baffles. This design forces incoming engine blow-by to move rapidly across the baffles, separating oil from the engine blow-by. Multiple layers of baffles mean more surface area to collect more oil, making for a compact and efficient design.

Oil entering from the crankcase vents spins counterclockwise through the entire body of the AOS, passing along four walls equaling roughly 50 sq/in of surface area. The multiple baffle walls in our compact design simulate the surface area of an AOS that is 13.5" tall!


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 as the engine blow-by. By keeping the air-oil separator at 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.

This vital feature eliminates nearly all the sludge that can build up in the air-oil separator body, which is a common problem with catch cans and other air oil separators.


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.


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


  • (1) PERRIN Air Oil Separator
  • (1) Car Specific Bracket
  • (1) PERRIN License Plate Frame
  • All necessary hardware for installation
  • Warranty & Instructions


  • 08-14 Subaru STI
  • 08-14 Subaru WRX
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