Details
To improve the performance of R35 GT-R using the factory Head gasket, the factory bore sealing proof stress restricts the improvement.
GT800 Package can release the restriction by replacing the Head gasket with the HKS Head Gasket which enables higher performance. This HKS Head Gasket includes the Exhaust Manifold Gasket. Best to use with GT800 Package to upgrade the engine properly.
Feature
POINT-1
High engine output parts. Designed to replace the factory Head gasket.
The bore diameter and thickness are the same as the factory gasket.
The shape of the exhaust gasket is the same as the factory gasket.
Improved the bore seal proof stress at high output and high boost by the redesigning the structure without upgrading the Head Bolt. (Bore seal pressure of the contacted surface was improved by 30%)
In-house test at 900PS confirmed the durability and safety.
The compression ratio of HKS Head Gasket isε9.0 which is the same as the factory ratio.
The Exhaust Manifold Gasket uses the 4-layer seal bead design (t=0.8). (The factory is 3-layer design (t=0.6)
POINT-2
To maintain the bore seal proof stress, the stopper's height was changed to 0.15mm from 0.10mm. Narrowing the width enables the high proof stress with the factory Head Bolt axial tension. Also, optimizing the bead plate's angle improved the seal pressure of the contacted surfaces of the oil and coolant seal parts without affecting the bore seal pressure of contacted surfaces. The surface of the gasket was fully coated instead of only bead part of the factory gasket's surface like the factory gasket. Fully coated gasket's surface can improve the rigid connection of the cylinder head and block when installing the gasket.
The Exhaust Manifold Gasket has the 4-layer bead plate comparing the factory 3-layer bead plate so the seal durability was improved to be used under high exhaust pressure.
The Performance requirement from Head Gasket.
As the cylinder block and head are not rigid body, when the Head Bolts are tightened, the gap between the surfaces and the surface pressure applied is not even across the whole surface. Moreover, due to combustion pressure and vibration while driving, the conditions are continually changing and the contact surface is being continually beaten. As a result, a good gasket must ensure that contact surface pressure is spread as evenly as possible and also adapt quickly to the ever changing gaps that can appear in the contact surface to maintain a good seal with good pressure.