Where Does Horsepower Really Come From?The origins of horsepower are simple on the surface, yet complex in detail. The basics tell us that atmospheric pressure pushes air and fuel into a cylinder, a piston mechanically squeezes that mixture, a spark ignites it, and the cylinder pressure created forces the piston down. The spent gases are then pushed out the exhaust valve and the whole process begins again.
Photo Gallery: Cubic Inches, Boost, Or RPM?