For N52B25 2.5L L6 E60 E90 E91 E92 E93 323i 325i 523i 525i 6pcs Pistons & Rings Set Φ82mm CR11:1 OE 11257612982 Pistons and rings set designed for N52B25 2.5L L6 naturally aspirated engine with a compression ratio of 11:1.Fits engines with 2497cc displacement.Bore diameter is Φ82.00mm.Piston wrist pin diameter is Φ20mm with a length of 46mm.Ring thickness: first ring 1.2mm, second ring 1.5mm, oil ring 2.0mm.Standard size specification with no cylinder expansion required.Set includes 6 pistons and corresponding rings.Compatible with vehicle models equipped with the N52B25 engine including 323i, 325i, 523i, 525i, X1, X3, Z4 across chassis types E60, E61, E81, E83, E84, E85, E89, E90, E91, E92, and E93 produced between 2005 and 2012.OE numbers: 11257612982, 11257561848, 11257561844, 11257542057, 40407600, 40444600, 31-04619-000, WG1016610.