The HKS redesigned Super Sequential Blow-Off Valve III (SSQV4) for the 2008-2014 WRX is a high performance dual stage pull-type blow-off/bypass valve capable on any turbocharged performance level, from bone stock to fully track prepped. Unlike typical push type blow-off valves, the SSQV4 can not leak under any level of boost as it is designed to keep the valve closed against its seat when under boost. Many similar valves use a push-type valve design with a large valve to accommodate high boost and high horsepower applications.
These large valves react slowly and require high pressure to open, and are not able to activate and prevent compressor surge at light-load conditions. On the other hand, smaller, fast reacting push-type valves do not discharge the airflow capacity required for high horsepower applications and tend to slowly open and leak as boost pressure overpowers the spring. For maximum performance, the SSQV4 incorporates both a small primary valve for ultra quick activation, and a larger secondary valve for additional discharge capacity. The SSQV4 is engineered to initially open the small primary valve at light throttle and load conditions, then sequentially opens the secondary valve for additional relief capacity under high boost and load conditions.
The SSQV4 is constructed of brushed aluminum and utilizes a circular mounting flange with a C-clip snap ring and O-ring gasket to ensure a perfect seal. The included triple-fin discharge port design produces a powerful, unique and aggressive blow-off sound. The HKS SSQV4 blow-off valve kit for the WRX includes everything needed to recirculate or vent boost without any additional fittings or hardware required.
Super easy to install, best sounding, AMAZING quality unlike some of the other brands I’ve tried in the past, 10/10 recommend and will buy for my future projects.