High-powered modified Subaru engines tend to generate excessive blow-by oil and gasses. In these cases, an ordinary small catch can may quickly fill with oil and not be adequate. Like the Radium Engineering , the AOS (Air Oil Separator) kit is responsible for keeping blow-by oil and other pollutants out of the intake pipe, manifold, turbocharger, and intercooler during all engine loads. The main difference is that an AOS-R system returns what is collected back into the oil pan so there is no servicing required. 

 The built-in heater keeps water from condensing in the AOS. And because water is more dense than oil, there is an integrated water trap found around the bottom perimeter of the can.

BENEFITS

• Effectively raises the octane and increases engine performance with cleaner inlet air
• Prevents oil buildup in the intake or intercooler system walls, throttle body, intake manifold, etc.
• Lowers hydrocarbon emissions

• 02-07 Subaru Impreza WRX
• 02-07 Subaru Impreza WRX STi
• 04-08 Subaru Forester XT
• 05-06 Saab 9-2X/Aero
• 09-13 Subaru Forester XT
• 08-14 Subaru Impreza WRX
• 08-14 Subaru Impreza WRX STi
• 15-21 Subaru WRX STi

NOTE: This product is not compatible with RHD vehicles. For RHD vehicles, our Universal AOS-R must be used for custom mounting and plumbing

• AOS Height: 6.3" (without fittings)
• AOS Diameter: 3.45" Round
• AOS Capacity: 20.3oz (600mL)

PORTS

• Inlet: 7/8"-14 threaded for 10AN ORB fittings
• Outlet: 7/8"-14 threaded for 10AN ORB fittings
• Return: 7/8"-14 threaded for 10AN ORB fittings
• Coolant: 7/16"-20 threaded for 4AN ORB fittings (x2)

• For 02-05 Subaru with a cable-actuated throttle body, our Cruise Control Relocation Bracket must be used
• If operated in freezing environments, Radium Engineering recommends installing insulation sleeving (not included) over any hose exposed to cold air flow. This will help prevent the natural phenomenon of water condensation freezing and potentially clogging the hose.
• The Radium AOS-R kit may not be compatible with all other aftermarket products.

• Machined alumium Radium Engineering Air Oil Separator
• Subaru specifically designed mounting bracket
• All necessary SAE J30R7 rated PCV/Emissions hose
• Coolant hoses and fittings
• All necessary aluminum fittings and hose-ends
• Stainless steel mounting hardware