HKS Metal Head Gasket (Supercharged Vehicles) - 2013+ FR-S / BRZ / 86

Metal Head Gasket for Supercharged FA20 Applications

The HKS Metal Head Gasket for supercharged 2013+ FR-S, BRZ, and 86 applications is an upgrade over the factory multi-layer steel gasket, designed to maintain head-to-block seal integrity under the increased cylinder pressure generated by forced induction. The FA20 head gasket is a known concern on supercharged and turbocharged builds. The OEM gasket sealing capacity is designed for naturally aspirated cylinder pressures, and boost changes the load on that gasket significantly. The HKS metal gasket addresses this directly.

Specs & Highlights

• Metal head gasket construction
• Designed for supercharged FA20 applications
• Higher sealing pressure than OEM multi-layer steel gasket
• Accommodates increased cylinder pressure from forced induction
• Available in standard and revised thickness options
• Fitment: 2013+ Scion FR-S / Subaru BRZ / Toyota 86 (supercharged builds)

Thickness Options, Compression Ratio Change per Spec

The HKS metal head gasket for supercharged applications is available in t=0.8mm, t=1.2mm, and t=1.5mm thicknesses, each changing the effective compression ratio. The t=0.8mm is the direct replacement for the OEM 1.2mm MLS gasket, it does not significantly change compression ratio. The t=1.2mm reduces compression ratio by approximately 0.3–0.5 points, appropriate for moderate boost applications. The t=1.5mm reduces compression by approximately 0.6–0.9 points, for higher boost builds. All use a stainless fire ring construction with nitrile rubber surface coating.

Why Boost Pressure Changes the Head Gasket Requirement

The head gasket sealing requirement increases with boost pressure because combustion pressure is higher and the pressure pulse at top dead center is more aggressive. The OEM FA20 gasket handles naturally aspirated pressures reliably; under sustained boost those loads can exceed what the gasket is rated for, particularly at elevated boost levels or in race applications. The HKS metal gasket is specified for the forced induction application and provides the additional clamping force and sealing area needed.

ARP Head Studs Are the Complementary Piece

Installation requires engine disassembly to the level of head removal. This is a significant job and is typically combined with other engine work. Head gasket replacement while the engine is apart for a turbo or supercharger installation, or as a proactive measure on a high-mileage forced induction build. ARP head studs are a recommended complement to the metal head gasket.

The FT Breakdown

If you are running the HKS GT2 supercharger system or a turbo kit on the FA20, the metal head gasket is the maintenance piece that prevents a more expensive repair later. The cost of the gasket and the installation labor is significantly less than the cost of diagnosing and repairing a failed OEM gasket under boost. The t=0.8mm thickness maintaining near-factory compression is the correct specification for builds where the compression ratio change needs to be managed by the piston selection rather than gasket thickness. For supercharged FA20 builds running the GT2 kit at standard boost, the 0.8mm provides the fire ring sealing improvement without altering the tune's compression assumptions.