Radium Engineering 2015+ Subaru STi Air Oil Separator-Return Kit

The Radium AOS-R (Air Oil Separator) is designed for high-powered modified Subaru engines to keep blow-by oil and other pollutants out of the intake pipe, manifold, turbocharger, and intercooler during all engine loads. The AOS-"R" system returns collected oil back into the oil pan, eliminating the need for servicing. It features a built-in heater to prevent water condensation and an integrated water trap that boils and evaporates water out of the system. The AOS is constructed of three CNC machined sections sealed with o-rings. It aims to effectively raise octane, increase engine performance with cleaner inlet air, prevent oil buildup, and lower hydrocarbon emissions.