Part Number: FCPPA815085RS4Manufacturer: FCP EngineeringForged high performance pistons for a variety of applications in almost all engine types for racing and street use.Made of 4032-T6, the bottom of the piston is molybdenum coated.Each piston kit also includes HD series rings and fittings.Diameter cylinder: 81.50 mm Compression ratio (CR): 8.5:1 Compression height: 30.80 mm Link diameter: 21 mm Piston stroke: 86.40 mmAudi S4 RS4 - 2.7 30V Biturbo