HKS Super SQV4 Blow Off Valve Kit - 2020-2023 Toyota GR Supra

SSQV4 Blow Off Valve Kit for the 2020-2026 GR Supra

The HKS Super SQV4 Blow Off Valve Kit for the 2020-2026 Toyota GR Supra is the latest generation of HKS's flagship sequential blow off valve, adapted for the B58 turbocharged straight-six. The SSQV4 vents boost pressure to atmosphere on throttle lift, producing the characteristic HKS blow off sound while eliminating the compressor surge that occurs when the throttle closes against boost pressure. On the B58 Supra at any significant boost level, a proper BOV is a functional upgrade as much as an auditory one.

Specs & Highlights

• HKS SSQV4 sequential blow off valve
• Vents to atmosphere on throttle lift
• Eliminates compressor surge
• B58-specific adapter kit
• Includes all hardware for direct installation
• Fitment: 2020-2026 Toyota GR Supra

38mm Valve, 3.0 Bar Operating Range

The SSQV4 uses a 38mm valve diameter, the same as the outgoing SQV3, but the internal sequential piston design is revised for faster response at lower differential pressures, meaning the valve begins opening sooner under partial-throttle lift events rather than requiring a full-pressure differential to actuate. The valve body is machined from aluminum with a hard-anodized finish. Operating range is rated to 3.0 bar (43 psi) gauge pressure, well above the B58's stock boost levels and appropriate for modified applications.

Sequential Design and Its Sound Signature

The SSQV4 uses a sequential valve design that opens progressively as boost pressure against the closed throttle increases. This sequential action produces the two-stage sound character that is distinctly HKS. The initial crack followed by the sustained whoosh, while managing the pressure release more smoothly than a simple poppet valve. The kit includes all adapters and hardware needed to mount to the B58 charge pipe.

Atmospheric vs Recirculation: Choosing Correctly

This is the vented-to-atmosphere version. For builds where recirculation is required to maintain closed-loop fueling on the stock ECU, HKS offers the recirculation kit (AT021V). For modified builds running an aftermarket ECU or where atmospheric venting is acceptable, the AT021 is the correct choice.

The FT Breakdown

The SSQV4 is HKS's longest-running and most recognized product globally and the Supra version maintains the same engineering standard. The B58 builds boost quickly and the sound profile of the SSQV4 on this engine is one of the better blow off signatures in the current market. If you are adding a BOV to the A90 Supra, this is the benchmark. At 95 dB(A) from the Super Turbo exhaust and the SSQV4 venting cleanly on every lift, the A90 Supra sounds like a car that has been properly attended to rather than one with random parts bolted on. These two HKS products work together sonically as well as functionally.