JE Pistons SUB STI EJ257 99.75mm Bore CR 9.5 KIT Set of 4 Pistons

JE Pistons is known for making well-built forged racing pistons, drawing on over 75 years of experience. They apply that knowledge to their wide range of pistons for European, import, and sport compact cars. This specific kit is designed for the Subaru STI EJ257 engine, featuring a 99.75mm bore and a 9.5:1 compression ratio. These pistons are engineered and machined entirely in the USA using 2618 aluminum, which offers the high tensile strength needed for demanding performance applications.

What sets these pistons apart is JE's proprietary Forged Side Relief (FSR) forging design. This design helps minimize friction and power loss by using a reduced skirt width. It also saves weight with a shorter wrist pin. Depending on the specific application, these pistons may also include an accumulator groove, which helps reduce pressure from combustion gases. This can reduce ring flutter and improve ring seal for more consistent power. Some applications also feature a skirt coating that reduces friction and wear on the piston skirts and cylinder walls, while also lowering operating noise. These pistons are designed specifically for the EJ257 engine and its intended use, aiming for optimized performance and durability.

This kit includes everything you need to get started: four forged pistons, high-quality wrist pins, locks, and JE Pro Seal premium piston rings. They are made 100% in the USA, ensuring a high standard of manufacturing. Please note that these pistons are not CARB approved and cannot be shipped to California.