JE Pistons SUB STI EJ257 Block w/ EJ20 Head 99.5mm Bore CR 8.5 (Left Side) Single Piston

If you're working on a Subaru EJ257 engine, this JE Pistons single piston is built for serious performance. It's designed specifically for the EJ257 block with an EJ20 head, featuring a 99.5mm bore and a compression ratio of 8.5:1. This piston is engineered to handle the demands of high-performance applications, whether you're on the track or the street.

JE Pistons uses 2618 aluminum for these pistons, which gives them the high tensile strength needed for demanding builds. They're forged and machined entirely in the USA, ensuring solid construction. This particular piston uses a proprietary Forged Side Relief (FSR) design, which helps reduce friction and power loss by using a narrower skirt. Some applications also include a skirt coating to further cut down on friction and wear, while also making the engine run quieter. An accumulator groove is also included on some designs to help manage combustion gas pressure, which can prevent ring flutter and keep your rings sealing consistently for reliable power.

This piston comes as a single unit and includes high-quality wrist pins, locks, and JE Pro Seal premium piston rings. It's important to note that this part is not CARB approved and cannot be shipped to California. Always refer to the manufacturer's installation instructions for proper fitment and assembly procedures.