SKU: SKU: HKS23001-AT003
Opposed Bead Stopper Type Metal Gasket for the FA20 engine of 86/BRZ provides higher bore sealing durability than a stock gasket.
2 types of the gasket are available. One is t0.5 increased compression ratio type for an NA engine (ε12.6←12.5, Supercharger installable, Endurable approximately 300ps)and another type is t0.7 high engine output type for a supercharged engine (ε12.4←ε12.5, Endurable approximately 600ps with supercharger)
＜POINT-1＞ t=0.7mm for Supercharged Engine
The t=0.7mm type utilizes a stopper taller than the t=0.5mm type to provide higher bore seal durability. With a stock pistons, the compression ratio is reduced only by 0.1; it allows to maintain high heat efficiency.
Compression Ratio
Stock Thickness: t=0.6mm (ε12.5) HKS Thickness: t=0.7mm (ε12.4)
＜POINT-2＞ Maintain a high seal with high pressure!
Both types are endurable against high engine output. Stopper structure of the bore seal is separated type so it prevents leakage even under high gas-pressure at high engine output.
＜POINT-3＞ Contact surface pressure is improved!
Special coating was applied on the head side and cylinder side to improve sealing performance when tightening the bolts.
＜POINT-4＞ Bore seal pressure was confirmed in figures. (See the diagram below.)
(Contact Surface Pressure Measurement)
(Structure Comparison)
NA t=0.5
* Comperd to stcok, bore seal is independent and has higher seal surface pressure, therefore same amount of stopper, bore seal is stronger.
* Thinner than stock and compression ratio is 0.1 highe
Supercharger t=0.7
* Comperd to stcok, bore seal is independent and has higher seal surface pressure, therefore bore seal power is much stronger.
* Thicker than stock and compression ratio is 0.1 less than stock
Stock t=0.6
* Bore stopper is similar to the other seal and the surface pressure polymerize, it has lower seal ability than the independent type
A high pressure seal is formed around the combustion chamber through the use of stoppers which create a step within the gasket for optimum sealing. By making the stopper part of the plate also allows the fold to be smaller while maintaining structural integrity. One side of the plate is completely flat meaning that it can be layered with the stopper to allow stoppers to be used in even the tightest of locations around the combustion chamber forming a high quality seal. Compared with other gaskets of the same thickness, there are more layers in these gaskets giving flexibility which allows the gasket to maintain a good seal even when the engine tries to vibrate and move.