What Does a Cold Air Intake Do? AEM Induction Systems Answers - The AEM CAI Debate

There is a lot of discussion among air intake system buyers leading many to ask What Does a Cold Air Intake Do? AEM is happy to provide answers concerning the function of an AEM CAI
There is a lot of discussion among air intake system buyers leading many to ask What Does a Cold Air Intake Do? AEM is happy to provide answers concerning the function of an AEM CAI
An AEM cold air intake system, like the CAI on this 2014 Mazda MX-5 Miata 2.0L L4, is designed to bring cooler air into the engine because cooler air has more mass
An AEM cold air intake system, like the CAI on this 2014 Mazda MX-5 Miata 2.0L L4, is designed to bring cooler air into the engine because cooler air has more mass

The general idea behind an air intake system is to remove the restrictive factory air filter box, and the maze-like ducting leading to the intake manifold and replace it with a low-restriction, oversized air filter, and a turbulence free air intake tube. This is done in an effort to reduce restriction and improve power. A true cold air intake advances this principal one step further and relocates the air filter outside of the engine compartment, usually near the front of the vehicle, with the goal of directing cool, dense, outside air into the engine for more efficient combustion.

Making more horsepower and torque isn’t just a matter of bringing more air into the engine. The displacement of the engine does not change, so therefore the amount of air an engine can use will not increase. Eliminating the restrictive factory air filter box and tubing will reduce restriction and improve efficiency, but that is just part of the equation. An AEM cold air intake system is designed to bring cooler air into the engine because cooler air has more mass. This is measured in lbs./mass and can be critical for performance. To provide a visual, think back to a time when you may have been physically active at high altitudes. The same level of activity is much more difficult at high altitudes than it is at sea level. This is because air density decreases with increasing altitude. The same holds true with temperature and humidity. As these factors increase, air density will decrease.

An AEM cold air intake, such as the AEM CAI for 2008-2014 Subaru WRX STi models, relocates the air filter with the goal of keeping inlet air temperature (IAT) at or near ambient air temps
An AEM cold air intake, such as the AEM CAI for 2008-2014 Subaru WRX STi models, relocates the air filter with the goal of keeping inlet air temperature (IAT) at or near ambient air temps
AEM cold air intakes are developed using Computational Fluid Dynamics (CFD) to calculate air pressure, speed, and temperature to make usable horsepower, safely, and consistently
AEM cold air intakes are developed using Computational Fluid Dynamics (CFD) to calculate air pressure, speed, and temperature to make usable horsepower, safely, and consistently

Back in 1994, when AEM began selling the first packaged air intake system, making power was easier than it is today. Modern cars are becoming increasingly sophisticated in an effort to squeeze power, fuel efficiency, and low emissions from every drop of fuel. This makes a true cold air intake system, like one from AEM, more important than ever before. The engine control unit (ECU) in modern cars will retard ignition timing as air temperature increases causing the engine to run more conservatively and in turn, making less power. This makes factors like the flow, temperature, and quality of incoming air important for maintaining peak performance.

As part of the cold air intake development process AEM uses thermocouples and ECU scanning tools to monitor temperatures along the inlet path, under the hood, and outside of the vehicle
As part of the cold air intake development process AEM uses thermocouples and ECU scanning tools to monitor temperatures along the inlet path, under the hood, and outside of the vehicle

AEM engineers design our intake systems as a fully integrated component of the vehicle. Significant testing is performed to assure proper airflow management with the goal of keeping inlet air temperature (IAT) at or near ambient air temperature. AEM will accomplish this with a cold air intake system by relocating the air filter outside of the engine compartment. Because maintaining near ambient inlet air temperature is so important to AEM some of our air intakes will incorporate an enclosed air box, additional air sources, or even a hood scoop when relocating the filter outside of the engine compartment is not feasible.

According to AEM Product Engineer John Conciadi "Excellent air inlet temperature management ensures consistent and reliable power.” This means that AEM cold air intake owners can feel confident knowing that their intake system is designed to make usable horsepower, safely, and consistently.

To find an AEM cold air intake for your vehicle, use the AEM Product Search on AEMintakes.com. AEM products are available for purchase online, or to find an AEM dealer use the Where to Buy link on AEMintakes.com.