A cold air intake is yet another way to try and improve the combustion efficiency of an engine. It works on the physical principle that cold air is denser than hot air and therefore has more oxygen per square inch. More oxygen in the cylinder at the point of detonation means a more powerful and more efficient combustion.

Turbochargers and superchargers also work to increase the oxygen content in the cylinder but they do so by forcing more air into it rather than relying on the properties of cold air. While these systems usually provide significantly more power, they are much more complex and more expensive. Cold air intakes often use a faced-forward, cone-shaped intake to increase the volume of cold air allowed into the cylinder.

Not all cold air intakes are alike and some perform significantly better than others. Cheaper types usually greatly increase engine noise and may only offer more power at certain RPMs. When you are shopping around for the right models for your car, look for versions that improve power at all engine speeds.

Cold Air Intakes Vary Widely in Performance and Design
Another factor that improves the performance of a cold air intake is the inclusion of a robust heat shield to help it fight off heat from the engine. These come in two main forms. The first is a metal pipe with insulation wrapped around it. The second is made from a composite, or carbon fiber, material that naturally insulates itself.