Cold air intake is a device used to bring lower temperature air into a car's internal-combustion engine, to increase engine power and efficiency.

Standard air intake systems tend to be very restrictive, in order to eliminate engine noise. Aftermarket cold air intake systems come in many different colors and sizes, and are easy to install when compared with other performance-increasing modifications. All cold air intakes operate on the principle of increasing the amount of oxygen available for combustion with fuel. Because cooler air has a higher density (greater mass per unit volume), cold air intakes generally work by introducing cooler air from outside the hot engine bay. However, the term "cold air intake" is often used to describe other methods of increasing oxygen to an engine, which may even increase the temperature of the air coming into an engine.

Some strategies used in designing cold-air intakes are:

• increasing the diameter of the air intake, allowing increased airflow.

• smoothing the interior of the intake to reduce air resistance.

• providing a more direct route to the air intake.

• tuning the length of the intake to provide maximum airflow at certain engine speeds (RPM).

• using a more efficient, less restricting air filter.

• cold air provides more oxygen for the engine to burn.

The short ram air intake is a form of aftermarket air intake for automobiles with internal combustion engines.

It basically replaces the OEM air intake with a short metal pipe and a conical air filter inside the engine bay. A significant increase in intake air volume will only occur in an engine where the factory intake piping was restrictive.

 A harmless but noticeable result of using a short ram air intake is an increase in intake noise, which may manifest as a sucking sound, and the loss of any silencing properties that the factory intake had.

Intake systems come in many different styles and can be constructed from plastic, metal, rubber (silicone) or composite materials (fiberglass, carbon fiber or Kevlar). The most efficient intake systems utilize an airbox which is sized to complement the engine and will extend the powerband of the engine.