CP Piston & Ring Set for Subaru EJ257 WRX STi - Bore (99.75mm) - Size (+0.25mm) - CR (9.0) - SINGLE

This is a single forged piston and ring set from CP Pistons, designed for Subaru EJ257 engines found in WRX STi models. You get one piston and a set of rings to match. This set is built to a 99.75mm bore size, which is a +0.25mm oversize from stock, and features a 9.0:1 compression ratio. These are intended for builders looking to refresh or upgrade their EJ257 engine with well-built components.

CP Pistons are known for their strong construction, using forged aluminum to handle the demands of performance engines. This particular set is designed for a 9.0:1 compression ratio, making it suitable for builds that might use forced induction or require a specific compression target. The +0.25mm oversize means these are meant for engines that have been bored out to this specific dimension, typically during a rebuild to clean up cylinder walls or increase displacement slightly.

Please note that this piston set is not CARB approved and cannot be shipped to California. Always consult your engine builder or a professional mechanic to ensure this piston set is the correct choice for your specific engine build and application.