HKS Super SQV4 Blow-Off Valve Kit - Honda Civic Type R FK8 | K20C1 (71008-AH009)

Upgrade your FK8 Civic Type R's blow-off valve with the HKS Super SQV4 — HKS's flagship sequential blow-off valve, now in an application-specific kit engineered for the 2017-2021 Honda Civic Type R (FK8) with the K20C1 turbocharged engine. The Super SQV4 delivers HKS's most advanced BOV technology with a distinctive sound, precise pressure control, and a direct-fit installation designed specifically for the FK8's charge pipe system.

Key Features:

• HKS Super SQV4 sequential blow-off valve
• Application-specific kit for Honda Civic Type R FK8
• Engineered for K20C1 turbocharged engine
• Sequential valve design for precise pressure control
• Direct-fit FK8-specific installation kit
• HKS motorsport engineering heritage
• 5.6 lbs (complete kit)

Performance Benefits:

• Precise Pressure Control: Sequential valve design provides more accurate and consistent pressure relief than conventional BOVs
• Protects Turbocharger: Vents charge pressure on throttle lift to prevent compressor surge and protect the K20C1's turbocharger
• Improved Throttle Response: Faster, more complete pressure venting allows the turbo to spool more freely on the next throttle application
• HKS Sound: Distinctive Super SQV4 blow-off sound — more refined than a traditional BOV
• Direct Fit: FK8-specific kit eliminates fabrication and ensures correct fitment
• Durable Construction: HKS quality materials and engineering for long-term reliability

Specifications:

• Brand: HKS
• Part Number: 71008-AH009
• Product: Super SQV4 Blow-Off Valve Kit
• Valve Type: Sequential (SQV)
• Application: Honda Civic Type R FK8 — K20C1
• Weight: 5.6 lbs (complete kit)
• Barcode: 71008-AH009

Fitment Information:

• 2017-2021 Honda Civic Type R FK8 — K20C1 2.0L turbocharged engine
• Note: FK8 Civic Type R specific — not for FK7 Civic hatchback, EK/EP/FD Civic Type R, or other Civic variants
• Note: Verify your Civic is the FK8 Type R (not FK7 Sport or other FK-chassis variants) before ordering
• Installation: Professional installation recommended

What's Included:

• HKS Super SQV4 blow-off valve
• FK8-specific installation kit (brackets, fittings, and hardware)
• Note: Refer to HKS installation instructions for complete installation procedure

Installation Notes:

• Professional installation recommended
• Allow engine to cool before working on charge pipe system
• Depressurize charge system before disconnecting pipes
• Remove factory blow-off valve or bypass valve assembly
• Install HKS SQV4 using FK8-specific kit hardware
• Connect boost reference port to intake manifold or charge pipe per HKS instructions
• Verify all connections are secure and leak-free before running engine under boost
• Test at low boost before full-throttle use

What is a Blow-Off Valve?

A blow-off valve (BOV) — also called a pressure relief valve or diverter valve — is a critical component in a turbocharged engine's charge system. When the throttle is closed suddenly after a period of boost (such as between gear changes or when lifting off the throttle), the turbocharger continues to spin and compress air momentarily. With the throttle closed, this compressed air has nowhere to go and creates a pressure wave that travels back through the charge pipe toward the turbocharger's compressor wheel. This reverse pressure wave — known as compressor surge — causes the compressor wheel to stall momentarily, creating the characteristic "chatter" sound and placing significant stress on the turbocharger's bearings and compressor wheel. A blow-off valve prevents this by opening when the throttle closes, venting the charge pressure to atmosphere (or recirculating it back to the intake) before it can create a surge event.

Super SQV4 — Sequential Valve Technology:

The "SQV" in Super SQV4 stands for Sequential Valve — HKS's proprietary blow-off valve design that uses a two-stage sequential opening mechanism rather than a conventional single-stage poppet valve. In a conventional BOV, the valve opens in a single motion when boost pressure overcomes the spring preload. The SQV4's sequential design opens in two stages: a small initial opening that begins venting pressure immediately, followed by a full opening as pressure builds. This sequential action provides faster initial response (reducing the time between throttle lift and pressure venting) while also providing a more controlled, progressive venting action that reduces the abruptness of the pressure release. The result is more precise boost control, faster turbo response on the next throttle application, and the Super SQV4's distinctive, refined sound character.

FK8 Civic Type R — K20C1 Application:

The 2017-2021 Honda Civic Type R (FK8) is powered by the K20C1 — a 2.0L turbocharged DOHC VTEC engine producing 306 hp and 295 lb-ft of torque in factory form. The K20C1 uses a twin-scroll turbocharger and a sophisticated charge system with a factory recirculating bypass valve (not a traditional BOV) that recirculates charge pressure back to the intake rather than venting to atmosphere. The HKS Super SQV4 kit replaces this factory bypass valve with the SQV4 unit, providing the improved pressure control and sound of a performance BOV while maintaining compatibility with the FK8's charge system. The FK8-specific kit (71008-AH009) includes all necessary hardware for a direct-fit installation without modification to the factory charge pipes.

BOV vs. Recirculating Bypass Valve:

The factory FK8 uses a recirculating bypass valve (also called a diverter valve or DV) that vents charge pressure back into the intake tract upstream of the turbocharger rather than to atmosphere. This recirculating design maintains the correct air-fuel ratio by returning the metered air back to the intake, preventing the rich condition that can occur when a traditional BOV vents metered air to atmosphere. The HKS Super SQV4 is designed to vent to atmosphere, producing the characteristic BOV sound. On the FK8's K20C1 with its direct injection system, venting to atmosphere has less impact on fuelling than on older port-injected engines, but it is worth noting that some FK8 owners may experience minor fuelling adjustments at low boost levels after BOV installation. Consult HKS documentation for specific guidance on the FK8 application.

HKS Super SQV4 Sound:

The Super SQV4 produces HKS's signature blow-off sound — a sharp, distinctive "pssh" on throttle lift that is more refined and controlled than the loud, abrupt sound of a large-diameter traditional BOV. The sequential valve mechanism contributes to the SQV4's sound character, with the two-stage opening creating a more progressive pressure release that sounds purposeful without being antisocial. For FK8 Civic Type R owners who want an audible BOV upgrade over the factory silent bypass valve, the Super SQV4 provides a satisfying sound that complements the Type R's performance character without being excessive.

Why HKS?

HKS is one of Japan's most respected performance parts manufacturers, with decades of motorsport heritage in Super GT, time attack, and drag racing. Their turbocharger, exhaust, suspension, and engine management products are trusted by professional race teams and enthusiasts worldwide. The Super SQV4 is HKS's flagship blow-off valve, representing the pinnacle of their BOV engineering and the product of decades of turbocharger system development. For FK8 Civic Type R owners who want the best BOV available for their platform, the HKS Super SQV4 is the benchmark choice.

Perfect For:

• 2017-2021 Honda Civic Type R FK8 owners wanting HKS Super SQV4 BOV upgrade
• FK8 builds wanting improved charge pressure control and turbocharger protection
• K20C1 builds wanting the distinctive HKS SQV4 sound over the factory silent bypass valve
• FK8 performance builds wanting direct-fit HKS BOV without charge pipe modification
• Anyone seeking HKS's flagship sequential BOV technology for their FK8 Civic Type R

Perfect For: 2017-2021 Honda Civic Type R FK8 owners seeking HKS Super SQV4 blow-off valve for improved charge pressure control, turbocharger protection, sequential valve technology, and HKS's signature BOV sound.

Pro Tip: Install at low boost first and listen carefully for any boost leaks at the BOV mounting point before running full throttle — a small leak at the BOV flange will cause boost loss and a hissing sound under boost that is easy to diagnose and fix before it becomes a problem.

Super SQV4 | FK8 Specific: 2017-2021 Civic Type R K20C1. Sequential valve technology. Direct-fit kit. Vents to atmosphere. 5.6 lbs. Not for FK7 or other Civic variants. Professional installation recommended.

Upgrade your FK8 Civic Type R's blow-off valve with HKS Super SQV4 — sequential valve technology, direct-fit FK8 kit, precise pressure control, and HKS's signature BOV sound.