Piston requirements for gasoline engines have changed dramatically in the last ten years. Several factors have combined to tax traditionally used alloys to their limits. This paper is concerned with the use of high silicon “hypereutectic” aluminum alloy in gasoline engine pistons. Problem areas with standard piston alloys are discussed, along with the benefits to be gained by the use of hypereutectic material. Manufacturing problems associated with the production of quality hypereutectic pistons are also discussed.