CP Piston & Ring for Subaru EJ257 WRX STi - Bore (99.5mm) - Size (STD) - CR (9.0) - 1 ea piece

This listing is for one CP Pistons forged piston, designed for Subaru EJ257 WRX STi engines. It features a 99.5mm bore size, standard (STD) sizing, and a 9.0 compression ratio. These pistons are built for performance applications where increased strength and reliability are needed over stock cast pistons.

CP Pistons are well-known for their robust construction, using high-strength aluminum alloys and advanced forging processes. This particular piston is forged, meaning it's shaped under extreme pressure, creating a denser, stronger grain structure that can better withstand the higher cylinder pressures and temperatures common in modified or performance-tuned engines. The 9.0 compression ratio is a good balance for many performance builds, offering improved power output without being overly sensitive to fuel quality.

When rebuilding or upgrading your EJ257 engine, choosing a strong piston like this CP unit is crucial for longevity and performance. Remember that this part is not CARB approved and cannot be shipped to California. Always refer to manufacturer specifications for proper installation and compatibility with your specific engine build.