8pcs N63 Engine Pistons & Rings Set 11:1 for 550i 750i X5 F01 F02 F03 E70 E71 N63 4.4L V8 11257613626 11257576475 8907510000 Material: Aluminum Engine Model: Designed for N63B44 4.4L (4395cc) V8 Twin Turbo Engine Engine Compression Ratio: 11:1 optimized for performance Cylinder Bore Diameter: 89mm for precise fit Piston & Ring Set: Includes 8 pistons and rings for complete engine rebuild Compression Height: 32.1mm to balance power and efficiency Pin and Bolt Length: 60mm included for secure installation This piston and ring set is engineered to match the specifications of the N63B44 4.4L V8 engine, proper fit and.The 11:1 compression ratio supports enhanced power delivery and improved throttle response.Constructed from aluminum, the components are designed for under stress conditions.The 89mm bore diameter and 32.1mm compression height align with engine design requirements for consistent performance.All necessary hardware is included for a full overhaul.Compatible with models equipped with the N63 engine; not suitable for N63.11 engine variant.Meets or exceeds OEM specifications with part numbers 11257576475, 11257556955, 11257574822, 11257574823, 11257617547, 11257613626, 8907510000.