CP Piston & Ring Set for Mitsubishi 4B11 Evo X - Bore (86.5mm) - Size (+0.5mm) - CR (10.0) Set of 4

This is a set of four forged pistons and rings from CP Pistons, specifically made for the Mitsubishi 4B11 engine found in the Evo X. These pistons are designed to be 86.5mm in bore size and are 0.5mm oversize, meaning they are intended for an engine that has been bored out to accommodate them. The compression ratio (CR) is set at 10.0:1, which is a common and well-balanced figure for performance applications, offering a good blend of power and reliability.

CP Pistons are well-known in the performance engine building world. These are forged from high-strength aluminum alloy, which is much stronger and more durable than cast aluminum. This strength is crucial for handling the increased cylinder pressures and temperatures that come with a performance-tuned engine, especially in a vehicle like the Evo X. The 0.5mm oversize means these are meant for an engine that has already been machined to this larger bore size, often done during a rebuild to restore cylinder integrity or to increase displacement slightly. The included rings are matched to the pistons and bore size to ensure proper sealing and oil control.

When rebuilding or modifying your 4B11 engine, using quality forged pistons like these from CP Pistons is a smart choice for longevity and performance. They are built to withstand the demands of a performance application. Please note that this part cannot be shipped to California due to emissions regulations.