JE Pistons Subaru EJ20 Head/EJ25 Block Ultra Series 3.927 in. Bore Kit Set of 4 Pistons

If you're building a high-horsepower Subaru EJ20 or EJ25 engine, these Ultra Series forged pistons from JE Pistons are a solid choice. They're designed to handle the extreme cylinder pressures that come with serious power adder builds, like turbocharging or supercharging. JE Pistons has packed a lot of advanced features into these pistons to make sure they perform reliably under demanding conditions.

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 stresses of high-boost engines. You'll also find a thermal barrier crown coating, which is a ceramic-based material that reflects heat back into the combustion chamber. This helps keep piston crown temperatures down and can improve how efficiently exhaust gases are scavenged. For reduced friction and wear on both the piston skirts and cylinder walls, a special skirt coating is applied, which also helps quiet down the engine, especially during cold starts. To ensure proper lubrication in the critical pin, pin bore, and small-end areas, these pistons feature optimized pin oiling. Plus, lateral gas ports are included to help maintain a strong ring seal even at high RPMs and under high boost, which is crucial for consistent power production.

These pistons are made from 2618 aluminum and come with high-strength, thick-wall wrist pins manufactured by Trend Performance. Every feature on these Ultra Series pistons is optimized for high-horsepower racing engines, and they are made 100% in the USA. Keep in mind that this kit is not CARB approved and cannot be shipped to California. You'll also want to refer to the manufacturer's installation instructions for specific details regarding assembly and break-in procedures for your build.