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Perrin Air Oil Separator for WRX & STi

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Perrin Air Oil Separator for WRX & STi
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Perrin Air Oil Separator for WRX & STi.

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.

Increase Intercooler Efficiency

The AOS 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 Detonation

The octane level of oil is very low. Anytime there is a significant amount of engine blow-by (oil) being put back into your engine, it reduces your fuel's octane level leading to detonation or knock, which will cause loss of power and engine failure.

PCV System Included

We designed the PERRIN Air Oil Separator kit based on the idea that using a PCV on the AOS outlet ensures proper crank case venting during light loads and helps reduce unwanted blow-by gases into your intake system. Incorporating a PCV reduces the smell from exhaust and keeps your intake tract clean.

Easy Disassembly For Cleaning

Over the years, a slight buildup may occur inside your AOS. This can be quickly taken care of by removing one bolt to access the inside for cleaning. This small feature is one of the many things that makes the PERRIN AOS stand out from the rest.

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 blow by. 

Heated by Coolant

The base plate of the the AOS is heated by coolant drawn from the engine. By keeping the AOS the same temperature as the engine and blow-by gases, water condensation is decreased allowing oil and water vapor to separate and pass through the can.

This vital feature eliminates nearly all the sludge that can build up in the AOS body, which drastically reduce how often you must clean it.

This is NOT a catch can

The PERRIN Air Oil Separator is not a catch can. Catch cans capture water and oil vapor filling with a sticky mess requiring it to be emptied. The PERRIN AOS separates engine oil from water vapor and allows it to drain back into the engine. Oil entering from the crankcase vents spins counter clockwise through the entire body of the AOS, passing along four walls equaling roughly 50.25 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!

As oil accumulates on all the walls, gravity pulls it to the bottom of the can where it drains back to the engine block while water vapor and air merge with the intake air and are re-burned in the engine. This means little maintenance or upkeep.

Subaru WRX 2002-2014
Subaru STi 2004-2015

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