Installing a cold air intake might help improve a car's gas mileage, but there's debate as to whether the modification is worth the cost.
The simple answer to whether it will improve gas mileage is yes. Factory-fitted air intakes suck hot air from the engine, which is less efficient than cold air in a combustion engine. Cold air intakes are fitted lower in the car and away from the engine, therefore sucking in cooler air. Cold air is denser and contains more oxygen, which means less gas is needed in the combustion process. It's estimated that a cold air intake can improve gas mileage by up to 8 mpg.
Depending on how much you spend on a cold air intake, it may take a long time to realize a return on investment. Further, it is ineffective in very hot weather.
Installing a cold air intake won't void your warranty, unless it directly causes a vehicle malfunction. For example, incorrect installation could cause engine failure.
