CP Piston & Ring for Subaru EJ257 WRX STi - Bore (99.75mm) - Size (0.25mm) - CR (8.2) SINGLE PISTON

If you're rebuilding the engine in your Subaru EJ257 WRX STi, especially for higher performance applications, a strong set of forged pistons is key. This single piston from CP Pistons is designed to replace one of your stock pistons, offering a durable and reliable component for your build. It features a 99.75mm bore, which is 0.25mm larger than stock, and a compression ratio of 8.2:1, suitable for boosted applications where you need to manage detonation.

CP Pistons are well-known for their forged construction, which makes them significantly stronger and more resistant to the stresses of high horsepower and boost compared to cast pistons. This piston is built to handle the demands of performance tuning and racing. The 8.2:1 compression ratio is a notable change from stock, allowing for more boost pressure before encountering knock or pre-ignition, which is crucial for maximizing power safely in an EJ257 engine. This piston is sold individually, so you can purchase exactly what you need for your rebuild.