CP Piston BMW N55B30/S55B30 (6 Cyl) 84mm Bore -9.7cc STD Piston - Set of 6

If you're rebuilding the engine in your BMW with an N55B30 or S55B30 6-cylinder engine, especially for performance applications, a strong set of pistons is crucial. These CP Pistons are forged from high-strength aluminum, designed to handle the increased cylinder pressures and temperatures that come with modified or high-output engines. They feature an 84mm bore and a -9.7cc dish, which is a standard configuration for many performance builds, helping to achieve a specific compression ratio when paired with the right cylinder head and gasket combination.

CP Pistons are well-known in the performance world for their robust construction. The forging process creates a denser, stronger grain structure compared to cast pistons, making them more resistant to detonation and mechanical stress. This set includes six pistons, enough for a complete engine rebuild. The standard bore size means they are intended to replace your original pistons without requiring an overbore, assuming your cylinders are in good condition. Proper ring groove machining and piston skirt design contribute to reduced friction and improved oil control, which are important for engine longevity and performance.

When undertaking an engine build of this caliber, it's important to ensure all supporting components are up to the task. This includes quality connecting rods, a balanced crankshaft, and appropriate engine management tuning. These pistons are a solid foundation for a powerful and reliable engine build, but remember they are not CARB approved and cannot be shipped to California. Always refer to the manufacturer's installation instructions for precise details on fitting and assembly.