amura is proud to bring you the next step in the evolution of powersport pistons. The new Hyperdryve line of pistons was specifically designed as an alternative to the OE for applications that call for the use of forged internals. The major advantage of Hyperdryve pistons is the ability to hold up under temperatures never before seen by cast pistons, without the extra cost of forged equipment.
Hyperdryve pistons are composed of a new hypereutectic aluminum alloy developed for use in the space industry. Engineered to maintain its high tensile strength up to 700°F (370°C), 50% higher than a conventional cast piston, this gives Hyperdryve the strength to perform under operating conditions normally reserved for forged pistons. Hyperdryve is the exclusive line of pistons for 250 and 450CC motocross bikes, as well as select sport quads.
Extensive testing went into our choice of material; the images below show two cast aluminum pistons that have been magnified to 1,000 nanometers. Both pistons were soaked for 100 hours at 600°F (316°C) to simulate operating conditions. It's easy to see that the conventional aluminum alloy's particles coarsen significantly; this weakening of the material's bonds will lead to a sharp drop in piston strength. The particles of Namura’s new aluminum alloy have only coarsened slightly, showing that they are still able to maintain a higher strength for longer periods of time.
Additional testing shows figure 1 that the biggest hardness drop occurs after 10 hours of use; Namura’s new aluminum alloy still maintains twice the hardness of conventional alloys, even after 20 hours!
Still not satisfied, figure 2 illustrates the comparison of our new material to a typical 4032 forged aluminum alloy. Measurements are noted in HRB on the Rockwell scale (a hardness scale based upon the indentation impression of the material) and MPa (megapascals, a unit commonly used to measure stiffness or tensile strength of materials).
This revolutionary alloy, combined with our already existing features of machined smooth anodized heads (for better heat reflection) & MOS2 coated skirts (giving you smoother startups & break ins) meets the demands of today's 4-stroke engines.
After spending 100 hours soaking at 600˚, the particles in the conventional cast piston have coarsened and loosened significantly, leading to a sharp drop in tensile strength. The particles in the Hyperdryve piston have only coarsened slightly, displaying the strength and durability of the material. Even after 100 hours at extreme conditions, the Hyperdryve piston retains a visibly higher tensile strength.