JE Pistons Subaru EJ257 Ultra Series 8.5:1 Comp, 99.75mm Bore, 83mm Stroker Piston Kit (Set of 4)

If you're building a high-performance Subaru EJ257 engine, especially one that will see significant boost, these Ultra Series pistons from JE Pistons are a solid choice. This kit includes four pistons, each with a 99.75mm bore and a compression ratio of 8.5:1, designed to handle the stresses of a stroker setup with an 83mm stroke. JE Pistons is known for making well-built internal engine components, and this kit is no exception, offering features typically found in custom piston applications.

What sets these Ultra Series pistons apart is JE's proprietary Aligned Grain Flow forging technology. This process maximizes the tensile strength of the aluminum, making them incredibly strong and able to withstand the extreme cylinder pressures that come with high-boost applications. They also come with a thermal barrier crown coating, which helps reflect heat back into the combustion chamber, reducing piston crown temperatures and aiding in exhaust gas scavenging. For reduced friction and wear on both the piston skirts and cylinder walls, a skirt coating is applied, which also helps quiet down engine noise, especially during cold starts. To ensure proper lubrication and reduce heat and wear in the pin bores and small-end, these pistons feature optimized pin oiling. Lateral gas ports are included to help maintain a strong ring seal, even at high RPMs and under high boost conditions. These pistons are built to perform in high-horsepower racing engines and are made 100% in the USA, including the premium thick-wall wrist pins from Trend Performance.

This kit is designed for serious engine builds and includes everything you need for the pistons themselves. Remember that these pistons are not CARB approved and cannot be shipped to California. For a complete engine build, you'll want to ensure you have all the necessary supporting components, such as rings, bearings, and gaskets, which are typically sold separately.