Hood scoop

Its upraised design allows it to effectively channel air directly into the engine compartment without the need to pass through the normal intake ducting.

Such effects are typically only felt at very high speeds, making ram air primarily useful for racing, not street performance.

[2] Some engines with turbochargers or superchargers are also equipped with top mounted intercoolers to reduce the temperature and increase the density of the high-pressure air produced by the compressor.

Channeling outside air to the intercooler (which is a heat exchanger similar to a radiator) increases its effectiveness, providing a significant improvement in power.

Under the hood, an effective scoop must funnel air into the engine's intake in as short and direct a path as possible, preferably through a tube or channel that is insulated against underhood heat.