What Does a Cold Air Intake Do, and How to Choose the Best One?

A cold air intake (CAI) is an aftermarket device that replaces the factory air intake system on a vehicle. Cold air intakes have been popular since the introduction of electronic fuel injection in the 1960s. While designs have changed over the years, they generally consist of an airbox, tubing, and a high-flow filter. Their affordability and impact on performance have made cold air intakes one of the most universally recommended vehicle mods.

What Does a Cold Air Intake Do?

The factory air intake pulls air from the engine bay, which gets hot quickly. A cold air intake kit moves the airbox further away from the stock location, thus pulling cooler air in. Since cold air is more oxygen dense than hot air, it creates stronger reactions in the engine. In other words, colder air equals more horsepower.

Aftermarket cold air intakes also use other techniques to reduce the temperature of the air they pull in. Many are made from materials with low heat conductivity or use a heat shield. Often the intake tubes are less restrictive.

The air filter itself is also an upgrade over the standard paper air filter. While the paper filter catches more dust, it also gets dirty and needs to be replaced. Cold air intakes typically come with higher-quality reusable filters. These are less restrictive, allowing for better airflow. You can also simply wash your air filter instead of replacing it.

Cold Air Intake Benefits

• Feeds the engine oxygen-dense air
• Improves airflow over the stock intake
• Boosts horsepower and fuel efficiency
• Improves throttle response
• Makes your intake louder
• Dresses up your engine bay

Does a Cold Air Intake Make a Difference?

In short, yes. Most vehicles' factory cold air kits do a good job of pulling oxygen-dense air into the engine. That said, aftermarket cold air intakes often have larger diameter tubing, smoother bends, and a high-flow filter. A new cold air intake can improve horsepower and torque, as well as throttle response. And since fuel is being used more efficiently, fuel economy is also better. A new cold air intake will also give your engine a more aggressive sound when you step on the gas.

People have seen significant horsepower and torque gains after installing a cold air intake, but the results vary. Some cold air intakes tout dyno-tested evidence that they can improve engine output by up to 30 horsepower. Of course, your vehicle’s current setup and existing equipment will impact those numbers significantly. Going with a tune-required cold air intake over a stock replacement will also impact your power gains.

Do You Need a Tune for a Cold Air Intake?

Needing a tune for your car’s ECU is dependent on which intake you decide to install. Intakes are divided into two categories. A tune-required intake, as the name suggests, requires you to tune your ECU on installation. A no-tune-required intake is a bolt-on upgrade that doesn’t need tuning.

The main difference between a tune-required and no-tune-required intake is the tube diameter. No-tune-required intakes use a smaller, stock-sized tube. This allows the ECU to maintain the stock settings while boosting performance with cooler air.

Can A Cold Air Intake Damage Your Engine?

A no-tune-required cold air intake, if properly installed and maintained, will not damage your engine. However, you have to be more careful with tune-required cold air intakes.

Tune-required intakes use a larger tube diameter for increased airflow to the engine. From the factory, the car’s intake tube is built to allow only a certain amount of air into the engine. As the air passes through it, the mass airflow sensor (MAF) captures the air mass data and passes it on to the car’s computer. The computer then determines how much fuel gets injected into the engine. If you change the diameter of the intake tube, you need a way to communicate that to the car’s computer. Therefore, a tune is required.

Without tuning the ECU, the MAF (Mass Air Flow) sensor won’t adjust the air-fuel mixture to handle the increased airflow. Having too much air and not enough fuel is known as running lean. When your air-fuel ratio is out of whack, there’s potential for catastrophic engine damage. As long as you properly install and tune your cold air intake, it should not cause any engine damage.

Will a Cold Air Intake Void Your Warranty?

It's good to be familiar with your car's warranty information. However, it's even more important to be familiar with the Magnuson-Moss Warranty Act of 1975. This law states that if an aftermarket part isn’t related to the repair, then the warranty is still in effect.

That means if you install a cold air intake in a vehicle that later has a faulty transmission, the repair would still be under warranty. There’s no way that a cold air intake could damage a transmission. But there are instances where you could be denied coverage under your warranty. For example, if the installation of the cold air intake was faulty and caused the engine to become air deprived, your warranty might be void.

While a cold air intake won’t generally void your factory warranty, a tune is a more intense and less warranty-friendly process. If you’ve got a factory warranty and keeping it is essential, then you should talk to your dealer before making any modifications.

Which Type of Cold Air Intake Is Right for You?

The table below is a basic comparison of a tune vs no-tune cold air intake. After you read through the detailed run-down of each option below, you can use the table as a quick reference while you shop.

Tune-Required Cold Air Intakes

Tune-Required Cold Air Intake in a Mustang GT

A tune-required cold air intake is the best option to get the most power and performance from your engine. You can get up to 30 hp in gains depending on the intake and vehicle. But there are some legal considerations to take into account.

Are Tune-Required Cold Air Intakes Legal?

If your Cold Air Intake doesn’t come with a CARB EO number, it isn’t legal in all 50 states. California created the CARB EO number system to cut down on emissions, and it’s been adopted in many other states. While you probably aren’t going to be pulled over and asked to pop the hood, your car might fail its next smog test and lose its street-legal status.

No-Tune-Required Cold Air Intakes

No-Tune Cold Air Intake in a Mustang GT

A no-tune-required cold air intake is the perfect mod if you want to add power to your ride without the hassle of a tune. You’ll see increased performance, gas mileage, and intake noise, without the risk of a voided warranty. But, the increase in these numbers won’t be as drastic as an intake/tune combo.

Does a No-Tune Cold Air Intake Need a CARB EO Number?

While a no-tune cold air intake may not void your warranty, some states still need it to have a CARB EO number. If you choose an intake without a CARB number, your car could fail its next smog test. This would make it illegal to drive your vehicle until you remove the cold air intake.

Intakes that Can Do Both

Can’t decide on whether you want to go for a tune or no-tune cold air intake? Why not both? There are intakes available that include a spacer for the intake tube diameter. This spacer allows you to restrict the airflow of a tune-required intake to factory levels. Then, when you’re ready to tune your ride, all you have to do is remove the spacer and perform the tune to enjoy the full power boost.

Can You Install a Cold Air Intake Yourself?

If you’re buying a cold air intake that’s specific to your vehicle’s make and model, installation is straightforward. The process is the same for tune-required and no-tune-required intakes, with the exception of engine tuning. Depending on the intake you choose and your skill level, installation should take less than an hour. For an idea of what the process involves, check out this cold air intake install video.

Check out our articles below for a list of install guides for cold air intake installs for various vehicles.

Upgrades that Complement a Cold Air Intake

A cold air intake is just one of a few easy mods you can make to improve your engine’s performance. Many enthusiasts also add one or several of these upgrades at the same time as their cold air intake.

Performance Air Filters

Most cold air intake kits come with a performance air filter, but don’t let that stop you from taking a look at your options. There are a variety of different filter styles and brands available, each with their own pros and cons. These include features like an oiled medium and a high-flow design. You can even clean and reuse some air filters. Read through our air filter guide for an in-depth look at your options.

Aftermarket Exhaust Systems

Now that your engine’s inhaling more cold air, you’ll want to help it exhale more efficiently. An aftermarket exhaust kit or a pair of custom headers is a great way to get harmful fumes out of your engine quickly. This will help open your engine’s airway for deeper, fuller breaths from your new intake.

Aftermarket mods also give you the opportunity to create a custom exhaust note with new mufflers and mid-pipes. Be aware though, certain exhaust mods, like headers, will require you to tune the engine. If you want an upgraded exhaust, it may be a good idea to install a tune-required cold air intake at the same time so you only have to tune your engine once.

ECU Tuners

If you only need a tune for your cold air intake, finding a tuner / cold air intake package is your best bet. Finding the right Mustang tuner by itself can be a big investment, but it pays off in the long run if you plan to add more performance mods to your vehicle.

Related: How to find your Mustang's ECU code