Dual Catch Can Kit PCV for Subaru WRX 15-21 Fluid Lock Radium Engineering - USA-RAD-20-0256-FL - COMPATIBILITY*15-21 Subaru WRX Not compatible with the Subaru S Ti Has not been tested on right hand drive models May not be compatible with some aftermarket intake systems.*Not compatible with the 2018+ Sport Lineartronic (CVT) Transmission An oil catch can is essential on a performance vehicle to protect the engine from elevated levels of crankcase blow-by accumulated from high performance driving. Excess oil saturated air circulating back into the air intake stream can lead to degraded performance. Radium Engineering catch cans feature large 10AN ORB ports, a 4AN ORB drain port, 2-step oil separation baffling, and an O-ring sealed dipstick. Features: -Effectively raises the octane and increased engine performance from cleaner inlet air -Prevents oil buildup in the intake and intercooler system walls, throttle body, intake manifold, etc. -Excessive oil collection can be an indicator of a damaged engine.-Lowers hydrocarbon emissions -Capacity: 7 fluid ounces each This kit is perfect for stock or modified street cars as a preventative measure to keep oil and sludge out of the intake tract, intercooler, and intake manifold. The direct-injected Subaru FA20F engine in particular has an inherent problem since there are no port injectors to clean the backside of the intake valves. The forward catch can intercepts the CCV line and the rear catch can intercepts the PCV line. The system is completely sealed and retains factory function of the PCV valve. The catch cans are sealed and will withstand pressure in boosted applications. Instruction PDF