Product Description
Fitment Information:
2008-2014 Subaru WRX
2005-2009 Subaru Legacy GT
Features:
Triple Fin design produces "Super Sound"
Silver Finish
High Quality Aluminum Die-Cast Body
Pull-type sequential valve structure
Stable operating ranges from low to high-boost pressures
Quickly relieves excess boost
The HKS Super Sequential Blow-Off Valve 4 (SSQV4) for the Subaru WRX and Legacy GT is unlike typical push type blow-off valves, the pull-type design of the SSQV4 makes this valve virtually impossible to leak under load, as it uses the boost pressure itself to seal the valve closed when on throttle. While imitators have also adapted this concept, they typically utilize only a single large pull-type valve.
These imitation valves react slowly, require high pressure to open and are not able to activate at light-load conditions. Traditional smaller push-type valves can react faster but lack the ability vents large boost pressures. The HKS SSQV4 has solved both of these problems by incorporating two sequential valves in one, a small primary valve for ultra quick activation and a larger secondary valve for additional discharge capacity. The SSQV4 is engineered to only open the small primary valve under light throttle conditions, and open the secondary valve for additional relief capacity under high boost and load conditions. If desired, the triple fin insert can be removed or swap with other inserts (not included) to produce a more customized sound. The HKS SSQV4 is designed as a 100% venting blow off valve, but can be modified to function as a recirculating valve with additional parts (not included).
Usually ships same or next day. 
