GrimmSpeed Head Gasket Set .78mm - Subaru STI 2008 - 2020

MFG: 124003

SEAL the deal with a set of GrimmSpeed EJ25 Head Gaskets!

GrimmSpeed has set the standard for quality when it comes to aftermarket replacement gaskets so it’s only natural that we should offer our fans the MOST important gaskets their car will ever need: Introducing The GrimmSpeed EJ25 Head Gasket Sets! 

Feature-packed, these gaskets are a perfect fit for any engine build, from basic refresh to a high horsepower track monster. 

The GrimmSpeed Head Gaskets feature a multi-layer steel (MLS) construction, in which multiple grades are used to provide optimal surface and combustion chamber sealing as they are torqued down. The top and bottom layers feature a Nitrile Rubberized Coating that helps accommodate a rougher RA surface finish of up to 50microinch. This acts to better seal the non-critical areas of the gasket. In addition, the gasket edge includes a folded stopper layer that allows for optimal sealing for the combustion chamber. This is done to help reduce the chances of combustion gasses causing head gasket failures under extremely high cylinder pressures that built engines can experience.

After talking to numerous engine builders/tuners it was clear that creating a variety of gasket thicknesses was key for pairing them with the right build. With that in mind, we’ve made the gaskets available in multiple thicknesses (.78, 1.1, 1.5mm) to help fine tune each individual build. In addition, the slightly oversized bore diameters will allow for up to 0.5mm overbore.

The EJ specific gaskets include enlarged center head bolt holes to accommodate up to a 13mm head studs. This is a popular upgrade option for many higher power builds, where additional cylinder head clamping force is needed.

We’ve outdone ourselves this time, The GrimmSpeed Head Gaskets carry on the legacy of quality that you’ve come to know from our other extremely popular gaskets.

Quick Specs

• Sold as a Set/Pair - Single and Dual AVCS fitment
• Die Cut Multi-Layer [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, ½” studs
• 0.78mm, 1.1mm and 1.5mm thickness (after crushing)

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

• 04-07 STI [EJ25 SAVCS]
• 06-14 WRX [EJ25 SAVCS]
• 04-08 FXT [EJ25 SAVCS]
• 05-09 LGT [EJ25 SAVCS]
• 08-21 STI [EJ25B DAVCS]