GrimmSpeed Head Gasket Set 1.1mm – 2008-2021 Subaru STI

GrimmSpeed Head Gasket Set (1.1mm), 2008-2021 Subaru WRX STI

The GrimmSpeed Head Gasket Set (1.1mm) for the 2008-2021 Subaru WRX STI is a multi-layer steel (MLS) head gasket set for the EJ257 engine. MLS construction provides superior seal durability under the elevated cylinder pressures of a modified turbocharged engine, it resists the head lift and combustion pressure that causes OEM gasket failures on modified builds.

DETAILS

• Thickness: 1.1mm
• MLS (Multi-Layer Steel) construction
• Superior seal durability over OEM composite gaskets
• Designed for elevated cylinder pressures
• Engine: EJ257
• Fitment: 2008-2021 Subaru WRX STI
• Application: moderate, overbored builds

OEM Subaru head gaskets are adequate at stock power levels but become a reliability concern when cylinder pressure rises significantly with modification. Increased boost, aggressive timing, or overboring all increase the peak cylinder pressure the gasket must seal. MLS gaskets use multiple thin steel layers rather than composite construction, more resistant to head lift and combustion pressure spikes.

The 1.1mm specification determines the effect on compression ratio, thicker gaskets lower compression, thinner raise it relative to a standard replacement. This must be matched to the engine’s bore dimensions and target compression. GrimmSpeed’s gaskets are manufactured to stated thickness within close tolerances for consistent compression across both cylinders.

What’s in the Box

• GrimmSpeed head gasket set (pair)

Why Choose GrimmSpeed

GrimmSpeed has been engineering performance parts for Subaru platforms from their Portland, Oregon facility since 2003. Everything they make is designed around real-world use, their engineers drive the same cars their customers drive, which means product decisions are made with genuine platform knowledge behind them. GrimmSpeed designs parts in-house, sources quality materials, and validates fitment on the actual application before release. The result is parts that install correctly the first time, perform as advertised, and hold up under the conditions Subaru owners actually subject their cars to. Whether it is a critical engine component or a cosmetic upgrade, the same attention to detail and fit quality applies across the catalog.

The RallySport Take

The GrimmSpeed MLS head gasket set is the correct choice for any EJ257 rebuild on a modified engine, overbored application, or build where OEM gasket durability has been a concern. Replace both cylinders as a set. Fits the 2008-2021 Subaru WRX STI.

Fitment