There are several schools of thought when it comes to forged versus hypereutectic pistons. Many engine builders believe that forged pistons are stronger and more durable than hypereutectic pistons. Hypereutectic pistons, on the other hand, offer superior heat dissipation properties and are less likely to suffer from piston slap. Ultimately, the decision of which type of piston to use depends on the application and the builder’s preferences.
Forged Pistons
Forged pistons are made from a single piece of metal that is hammered or pounded into shape. The forging process aligns the grain structure of the metal, making it stronger and more resistant to cracking and wear. Forged pistons are also typically lighter than hypereutectic pistons, which can result in quicker throttle response and reduced engine vibration.
Hypereutectic Pistons
Hypereutectic pistons are made by casting molten metal into a mold. The addition of silicon to the alloy creates a “skin” on the piston surface that is harder than the rest of the metal. This skin helps to dissipate heat better than a forged piston, which can be important in high-performance applications where engines tend to run hotter. Hypereutectic pistons are also less likely to suffer from “piston slap” – a condition caused by clearance between the piston skirt and cylinder wall that results in noise and reduced performance.