HKS SSQV4+Bypass Valve RETURN KIT for HKS R/S - 2020+ Toyota Supra

SSQV4 Bypass Valve Return Kit for the 2020+ GR Supra

The HKS SSQV4+Bypass Valve Return Kit for the 2020+ Toyota GR Supra is the recirculation version of HKS's SSQV4 blow off valve system, designed for Supra builds running the HKS R/S intake or where atmospheric venting would cause fueling issues on the factory or lightly modified ECU. The return kit routes vented boost pressure back into the intake tract upstream of the compressor rather than venting to atmosphere, maintaining the closed-loop fueling the ECU expects while still protecting the turbocharger from compressor surge.

Specs & Highlights

• SSQV4 blow off valve with recirculation function
• Returns vented pressure to intake tract
• Compatible with HKS R/S intake system
• Prevents fueling issues on stock/lightly modified ECU setups
• Includes all hardware and adapters
• Fitment: 2020+ Toyota GR Supra

25mm Return Line and Recirculation Volume

The AT022V return kit uses a 25mm (1 inch) recirculation outlet pipe that connects from the SSQV4 outlet back to the HKS R/S intake pipe upstream of the compressor inlet. The return connection point on the HKS intake pipe is located approximately 150mm ahead of the compressor inlet face, ensuring that returned air has sufficient mixing length before re-entering the compressor. The recirculation volume returned per blow-off event on the B58 at 7 psi is approximately 0.4–0.6 liters of air at intake charge pressure.

Why MAF-Based ECUs Need Recirculation

The choice between atmospheric (AT021) and recirculation (AT022V) BOV comes down to your ECU configuration. On mass-airflow based ECUs. Which the A90 Supra uses, venting to atmosphere means the ECU has already metered the air that is being dumped out, causing a brief over-fueling condition when the throttle reopens. On a stock or lightly tuned ECU this can cause stumble or rough idle. The return kit eliminates this by keeping the metered air in the system.

This Kit is for the HKS R/S Intake Only

This kit is specifically designed for use with the HKS R/S (Racing/Street) intake system. The inlet dimensions and routing are matched to the HKS intake path. If you are running the HKS intake, this is the correct BOV kit. If you are on the stock intake or a different aftermarket intake, verify compatibility before ordering.

The FT Breakdown

The SSQV4 mechanism is identical in both the AT021 and AT022V. The difference is purely the outlet routing. You get the same valve quality and HKS engineering regardless of which version you run. Choose based on your intake and ECU setup, not on sound preference. The 0.4–0.6 liter return volume per blow-off event on the B58 at 7 psi is not trivial — that is air the MAF has already measured, and dumping it to atmosphere means the ECU fuels for air that never makes it to combustion. The AT022V prevents that cycle entirely, which is why consistent throttle response on re-application is noticeably better with the recirculation setup on a stock ECU.