Precision Works Oil Control Valve Subaru 2008-2014 WRX & 2008-2014 STi EJ25

Engineered and machined in-house at PLM using our latest Haas 5-axis CNC machines, this High Performance Oil Control Valve is designed to solve one of the biggest weaknesses of the Subaru boxer platform—oil surge in the cylinder heads under hard cornering. When lateral G-forces push oil into the valve cover ports, traditional PCV, A/O separator, and catch-can systems can quickly become overwhelmed. This leads to falling oil levels, increased risk of oil starvation, and in extreme cases, overflow onto hot engine components.

Adapted from a proven design long used in aerobatic aircraft, our Oil Control Valve automatically prevents oil from exiting the head ports during high lateral loads while still allowing full crankcase ventilation under normal driving, acceleration, and braking. The system closes only the affected head port during severe cornering while all other ports continue to operate normally—maintaining proper blow-by evacuation with no negative impact on engine performance. The result is a safer, cleaner, and more reliable setup for track enthusiasts who push their Subaru to the limit.