The PERRIN Performance 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.
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 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 valve train.
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.
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
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.
This is not a catch can
The PERRIN Air Oil Separator is not a catch can. Catch cans capture and water and oil vapor filling with a sticky oily 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 reburied in the engine. This means no maintenance or upkeep.
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.
Application Specific Mounting Brackets
Each kit comes with specific mounting brackets and instructions to install your AOS perfectly in your engine bay or adapt our simple 2 hole mounting bracket for custom installations.
2002-2007 WRX - 2002-2005 WRX installation requires the removal of cruise control module.
2015-2020 WRX - Modifications may be needed if installed with after-market air intake box, contact tech for further details.
2015-2020 WRX- Does not work on vehicles with EyeSight.
*For left hand drive cars only.