Universal Air Oil Separator-Return AOS-R VTA Radium Engineering - USA-RAD-20-0819 - A high powered modified engine tends 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 Catch Cans, the AOS-R (Air Oil Separator, Return) is responsible for keeping blow-by oil and other pollutants out of the air intake, intercooler, manifold, etc. The main difference is that an AOS-R system returns oil back into the pan. This permits a service-free system. IMPORTANT INSTALLATION NOTES: -For the AOS-R to function properly, a return port on the engine must be available on the engine to the oil pan.-The AOS-R must be mounted high enough in the engine bay so that the port on the bottom is higher than the engine return port.-For heating purposes, engine coolant must be routed to the AOS-R to prevent condensation. Without a properly designed air oil separator, water condensation can develop and find its way in the oil pan contaminating engine oil. Engine coolant lines are routed through the Radium Engineering AOS-R via the 2 barbed fittings. The coolant enters a specially designed heating chamber Benefits-Lowers hydrocarbon emissions-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 Included-Machined alumium Radium Engineering AOS-R-Aluminum mount that permits 360 degree rotation-Two 5/16" barbed fittings for coolant lines-Stainless steel hardware  Ports Inlet Port(s): 7/8"-14 threaded for 10AN ORB fittings Outlet Port (VTE only): 7/8"-14 threaded for 10AN ORB fittings Return Port: 7/8"-14 threaded for 10AN ORB fittings Coolant Ports: 7/16"-20 threaded, includes two 7mm (or 5/16") barb fittings  Measurements AOS-R Height: 6.7" (without fittings)AOS-R Diameter: 3.45" Round AOS-R Capacity: 20.3 oz (600m L) 20-0819 AOS-R, Universal, VTA The vent-to-atmosphere air-oil separator has 2 side (inlet) ports. This is great for dual bank engines that have 2 crankcase vent ports. NOTE: For single crankcase vented engines, simply plug one of the inlet ports with Radium Engineering 14-0351. The VTA AOS-R features one giant non-restrictive outlet that is over 183% larger than the inner diameter of the 10AN inlets. This increase in volume slows air flow allowing contaminants to fall out of suspension. Additionally, contaminants are trapped with a diffuser permitting the oil sludge to fall back into the catch can preventing overspray in the engine bay. Furthermore, it is a dual stage design (located in the inlet and outlet). These free flowing chambers do not create any flow restriction. The included bracket system provides a ton of flexibility and permits full 360 degree rotation. Additionally, M6x 1mm hardware is provided for chassis mounting. NOTE: Because of the vented "air leak" in the system, the VTA AOS-R is not recommended for mass-air flow (MAF) sensor engines. Instruction PDF