Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve their air flow. Cylinder heads, as manufactured, are usually suboptimal for racing applications due to being designed for maximum durability. Ports can be modified for maximum power, minimum fuel consumption, or a combination of the two, and the power delivery characteristics can be changed to suit a particular application.
A mold of the suboptimally designed ports of a Ford two-liter head for use in Formula 2000 racing. It is shown as manufactured with the intake port on the right.
Port molds of a highly developed 500 cubic inch aftermarket Pro Stock racing head. Note the height and straightness of the ports, particularly the exhaust port on the left. This design is based on a cylinder head casting purpose-built for racing modifications. The head is supplied with small ports with ample material everywhere for porting specialists to shape to their requirements without having to weld on additional metal.
An intake is an opening, structure or system through which a fluid is admitted to a space or machine as a consequence of a pressure differential between the outside and the inside. The pressure difference may be generated on the inside by a mechanism, or on the outside by ram pressure or hydrostatic pressure. Flow rate through the intake depends on pressure difference, fluid properties, and intake geometry.
Dassault Super Mystère showing entry to engine intake duct
Automotive intake assembly showing pink air filter, plastic ducting with sensors, metal throttle body and plastic manifold with plenum and runners
