Editing Cold air intake (section)

{{Short description|Parts to bring cool air in a car engine}}
[[File:Mustang-v6-roush-intake.jpg|thumb|275px|Example of a [[Roush Performance|Roush]] cold air intake system installed on a [[Ford Mustang (sixth generation)|sixth generation Ford Mustang]]]]
[[File:2009-2014 Honda Ridgeline engine bay-air intake system.png|thumb|275px|Illustration of how the [[Honda Ridgeline (first generation)|first generation Honda Ridgeline]]'s cold air intake system gets fresh air forward of the radiator and into its [[airbox]] using an air channel created by the bulkhead cover and rubber seals under the engine's hood.<ref name="Flint Video Part 3">[https://www.youtube.com/watch?v=uzkyAuzpjwY 2006 Honda Ridgeline introduction (part 3 of 4), Ridgeline's Chief Engineer (Gary Flint) introduces the Ridgeline], YouTube, by The Temple of VTEC, posted by Jeff Chambliss on 1 August 2009, last accessed 16 August 2015</ref>]]

A '''cold air intake''' ('''CAI''') is usually an [[Aftermarket (automotive)|aftermarket]] assembly of parts used to bring relatively cool air into a [[Automobile|car]]'s [[internal-combustion engine]].

Most vehicles manufactured from the mid-1970s until the mid-1990s have thermostatic air intake systems that regulate the temperature of the air entering the engine's intake tract, providing warm air when the engine is cold and cold air when the engine is warm to maximize performance, efficiency, and fuel economy. With the advent of advanced emission controls and more advanced fuel injection methods, modern vehicles do not have a thermostatic air intake system and the factory-installed air intake draws unregulated cold air.  Aftermarket cold air intake systems are marketed with claims of increased engine efficiency and performance. The putative principle behind a cold air intake is that cooler air has a higher [[air density|density]], thus containing more oxygen per volume unit, than warmer air.