CP Piston & Ring Set for Subaru EJ25 WRX STi - Bore (100.0mm) - Size (+0.5mm) - CR (10) - Set of 4

Forged from 2618-T61 aluminum, these CP Pistons are built for serious performance in your 2004-2012 Subaru Impreza WRX STi. The 100.0mm bore size, combined with a +0.5mm oversize, is designed to work with a specific engine build, typically when the cylinders have been bored out to accommodate larger pistons for increased displacement and improved airflow. This set includes four pistons and the necessary rings, ready for installation into your EJ25 engine.

CP Pistons are well-known for their robust construction and attention to detail. These pistons feature a 10:1 compression ratio, which strikes a good balance between power output and pump gas usability for many performance applications. The 2618-T61 aluminum alloy offers excellent strength and durability, crucial for handling the increased cylinder pressures and temperatures found in modified or high-performance engines. Each piston is precision-machined to ensure a consistent fit and reliable operation.

This set is intended for builders who are undertaking a performance engine rebuild. It's important to note that these pistons are not CARB approved and cannot be shipped to California. Ensure your engine builder is aware of the specific requirements for installing oversize pistons, including proper cylinder honing and ring gap setting, to achieve optimal performance and longevity.