GrimmSpeed Head Gasket Set - Subaru EJ25

Stainless] Steel (MLS) Construction - Provides smooth edge finish and consistency from batch to batch, ±0.001” manufacturing tolerance Folded Stopper Layer to Better Seal the Combustion Chamber .25micron Nitrile Rubber Layer Coating - Reduces chances of leaking on imperfectly smooth mating surfaces over non-coated gasket. Accommodates up to 100.0mm bore Compatible with up to 13mm, 1⁄2” studs TESTING: GrimmSpeed High Performance Head Gaskets are designed to optimize combustion chamber sealing. This is done by using a unique gasket design feature which sets us apart from the competition. By strategically undercutting the middle layer of the gasket near the combustion chamber, we can control the crushing of outer layers, which in turn creates a perfect seal around the combustion chamber. We can visually demonstrate this feature by using pressure sensitive film and compressing the gasket in a manner which mimics the tightening of a head against the block. The film changes colors from white to pink to red as pressure is applied to denote areas of high and low pressure application. This information will then allow for easy visual verification of effectiveness in sealing of a gasket against a surface. As seen in the results, the combustion chambers are sealed evenly and equally around the circumference of the cylinder by the deep part circles. This visual representation is showing that combustion gasses are going to be held in the chamber and directed towards pushing the piston instead of escaping. Failure of a gasket to seal with even pressure around the circumference of the cylinder would be detrimental for performance and reliability of a gasket and would most certainly result in failure. When combining the perfect sealing, nitrile coating and other features of the gaskets, we are able to ensure that your engine build is ready for anything that you throw at it. From basic engine refreshes to full blown race builds, The Mark of Innovation from GrimmSpeed keeps you in control under pressure! FITMENTS: Single AVCS: 2004-07 Subaru STI 2006-14 Subaru WRX 2004-13 Subaru Forester XT 2005-12 Subaru Legacy GT 2005-09 Subaru Outback XT Dual AVCS: 2008-21 Subaru STI