One of the most common questions is about which piston to buy. The marquee is one factor, but sometimes we have to choose between a cast and forged piston. This article cannot give you the definitive answer to which piston to use, but some facts must be shared based upon experience. A cast shaped component means that the material has been melted and then poured into a mold that basically shapes the piston. The advantages are many, for example: a possibility to add other components like silicone, carbon, zinc and so on in order to gain certain properties. The aluminum itself doesn't build up inner tension as much. It is cheap. The density of the material doesn't increase which means it could be kept light. There are disadvantages also, of course. The piston will be weaker in structure. It is often heavier since the manufacturer has to increase wall thickness in order to achieve sufficient strength. The heat expansion cannot be controlled and is therefore often not completely round since the piston pin requires some material on the inside. They are also produced in bulk with most manufacturers only producing sizes that are close to factory specifications. This also makes them more affordable.
Forged pistons are mechanically shaped into a piston shape. They are hammered into a mold forming the piston and by utilizing state-of-the-art CNC machines, most manufacturers can maintain exact specifications and tolerances. This makes them structurally more durable. Forged pistons are well known in the racing and performance industry because of their ability to withstand more heat, higher rpm's, higher boost and higher temperatures. Another advantage to a forged piston is that they can be individually made to any custom size or specification without the high cost of casting. Here at LC Engineering, the philosophy is quit simple. The choice between using a cast piston or a forged piston is dictated by the application. If you plan on running normal octane gas and it falls into our "street" application, we recommend using the cast aluminum pistons. If you plan on using high octane, high compression or high boost for your application, then we recommend using a forged aluminum piston.
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