Perrin Air Oil Separators w-FMIC - Fits Subaru WRX 2002-2014 - STI 2004-2014

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.

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 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.