General Guide to Cold Air Intakes: Benefits, Questions, Myths and More

General Guide to Cold Air Intakes: Benefits, Questions, Myths and More

Cold air intakes are widely regarded as the best first upgrade to make on your car for those interested in aftermarket performance parts. I do agree, unless you are planning to add a forced air induction system such as a supercharger or turbocharger. In which case, you can skip the cold air intake.

I have poked around the internet reading about the pros and cons of cold air intakes for some time. I have to say that I was quite disappointed in the information I have read. There is tons of different statements that are made and plenty of “experts” giving information that is simply false. I am going to give you my general guide for cold air intakes and dispel some false beliefs. If you are left with any questions, post them down in the comments.

Benefits of Cold Air Intakes

  • Increase in horsepower
  • Increase in torque
  • Increase in fuel efficiency
  • Added “roar” during acceleration

Disadvantages of a Cold Air Intake

The major disadvantage of having a cold air intake is that it voids your car’s warranty. Another disadvantage to having a cold air intake is that you need to periodically clean the filter and apply oil. You should be periodically cleaning your stock air box anyway. Note that not all cold air intakes need to be oiled, it depends on the model you choose.

How Cold Air Intakes Work

The science behind cold air intakes is sound and fairly straightforward. Cold air intakes are designed to give your car a boost in horsepower while being an inexpensive upgrade and easy to install. Cold air intakes accomplish this by two main mechanisms. The first way this is accomplished is by having a straighter and wider intake tubes. The tubes that get installed with a cold air intake is straighter and wider than the factory intake tubes which allows more air to reach the engine at the same time. The air filters have more surface area than the factory air boxes which allow more air to enter. The air filters are also thinner than the stock filters which make it easier for more air to pass. The second major way cold air intakes function is by supplying the engine with colder air. The longer intake tubes allow air to be taken in further away from your (hot) engine which is a cooler environment. Colder air increases the efficiency of engines because colder gas is more dense than warmer gas. Denser gas allows a higher amount of oxygen in the same amount of oxygen.

Components of A Cold Air Intake

air ducting components, air intake tubes, brackets, mounting plates, air intake hoses, coupler and hose clamps, heat shield, couplers, reducers, silicone funnels and mass air flow sensor accessories.

Installation of A Cold Air Intake

Installing a cold air intake is pretty easy and straightforward which is part of the reason why so many like to do it on their cars. I would like to give you detailed instructions but the standard intake systems vary by car make and model. The first thing you need to do is identify the components that you will be removing. This is going to consist of intake tubing and the factory installed air box. When you have the hood of your car open, you should be able to identify the engine. From the engine, you will see a long black tube connecting to a plastic box. This black tube is the intake tube and the black plastic box is the air box. The intake tube connects to the throttle body on the engine.Before beginning the install disconnect the car’s battery.

There may be wires connecting to the airflow sensor system which you need to disconnect before removing. Remove the intake tube first, before removing the air box. Disconnect the intake tube from the throttle body and the air box. Then remove the air box which is typically bolted down.

Next, you connect your cold air intake components to the direct locations from where you removed the factory parts. Remember to reconnect any sensors. After you connect your intake tube or intake pipe to the throttle body, you are ready to connect it to the intake. You want your intake to be as far away from the engine as possible (because the engine is hot). Look around under your hood by your front headlight and grill area. There is usually an inlet designed for ambient air to flow. This is the air that you want to flow into your intake. Position your intake to be in line with air inlet as much as you can.

One mistake many people is that they throw away the intake system that was already installed. Be sure that when you remove the previously installed intake system that you do not throw it away. Store it somewhere safe. You never know when you want to put it back on.

Points To Consider When Installing A Cold Air Intake

Install a Heat Shield

Not all cold air intakes come with a heat shield. I would never install a cold air intake without a heat shield. A heat shield prevents hot air traveling from the engine into the intake. Without a heat shield you are working against your purpose. Heat shields are also called air dams.

Make Sure Your Cold Air Intake Fits

You don’t want a cold air intake that isn’t going to fit under your hood. Confirm beforehand that your cold air intake will fit to avoid a big headache. I have also seen cases where the hood crushes portion of the intake that was connecting to the intake manifold. This severely obstructed the airflow and completely defeated that person’s goal. Don’t let this be you.

Mass Airflow Sensor

All modern cars have an electronic control unit (ECU). The standard intake tube that comes in your car has a sensor in it called a mass airflow sensor (MAF). This is an important sensor. It signals to your ECU how much air is being drawn towards the engine so your car can maintain the air:fuel ratio in proper balance. Some cold air intake kits come with MAF and some don’t. If your kit doesn’t come with a MAF, take your stock MAF and install it in your new intake tube.


The ECU is basically a computer that monitors and maintains the processes of your car’s engine. A key feature of the ECU is to maintain the air:fuel ratio. To do this the ECU needs the MAF to be connected. So please be sure that you don’t forget to have a MAF installed alongside your cold air intake. Another thing is that not all ECUs are created equal. Certain ECUs will be able to adapt on their own to a new intake. Other ECUs are not able to do this on their own and will require tuning. Expect an ECU tuning to cost $300-$500 USD.

Upgrades that go along with cold air

Some people choose to make additional related upgrades. These include:

  • Ported intake manifold
  • Throttle body
  • Exhaust
  • ECU
  • Heat shield
  • Air bypass valve

Commonly Asked Questions

Is the air reaching the engine actually colder when using a cold air intake in comparison to the stock air box?

Based on measurements I have seen, the air being delivered to the engine through a cold air intake are either slightly cooler or the same temperature as the stock air box. In both of these scenarios there was extra horsepower being generated by the engine. The reason for this is that the decrease in temperature is only one of the ways in which a cold air intake increases horsepower. So even if the temperature of the air is the same, if the cold air intake allows more air to reach the engine it can still increase the engine’s horsepower.

Can I Use a Cold Air Intake Along with a Turbocharger?

You absolutely can use a cold air intake with a turbocharger. However, the vast majority of people using turbochargers opt to use an intercooler to cool their air. You can definitely use both an intercooler and a cold air intake together, but at that point it’s most likely going to be overkill and useless depending on your particular situation. It can however still make your car sound cool.

Are Cold Air Filters Bad For Your Engine?

Cold air filters are not bad for your engine. In fact, when installed properly with a properly tuned ECU they are actually beneficial for your engine.

Are Cold Air Intakes Legal?

In the United States certain cold air intakes are legal in certain states. California is often thought of as the most stringent state in regards to pollution laws. California has a smog law which declares that aftermarket parts must meet smog requirements. If you plan on driving your vehicle in the state of California with a cold air intake you should check that it is CARB-certified which indicates that the particular part has passed inspections. Several other states have jumped on the bandwagon and now has the same smog law as California. These states include Arizona, California, Connecticut, District of Columbia, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington.

Do Cold Air Intakes Make A Lot of Noise?

Cold air intakes do add noise when you rev your engine. I describe the sound as a roar or growl. Some people describe it as a whistle. The added noise is a feature that car enthusiasts find attractive.

How do Cold Air Intakes Increase Fuel Efficiency?

As a surprise to many, cold air intake do typically increase a car’s fuel efficiency by a couple miles per gallon. It may seem counter intuitive because simple logic dictates that more air flowing into your engine means more fuel has to be burned to maintain the air:fuel ratio. Where this simple logic goes wrong is that it is not taking efficiency into account. Firstly, cold air intakes provide a denser, more consistent airflow into the engine. This ensures that there will not be unburned fuel left after combustion and the engine will not have to work to correct it. Cold air intakes also allow the vehicle to accelerate at at lower rpm levels when under the hood conditions are hot further increasing the efficiency of the engine.   

What Does it Mean if Your Check Engine Light Goes On?

It’s not typical for a car’s engine light to turn off after the install of a cold air intake but it does happen. This should not be ignored because your car is telling you that something is wrong. The potential problems include an air leak, missing or improperly installed mass air flow sensor, dirty mass airflow sensor, or the ECU needing a reset. Start by checking your install. Make sure your new parts are secured well and prone to coming loose. Inspect for air leaks. There is a chance that you put in your mass airflow sensor in backwards. Clean your mass airflow sensor If this is not the case an ECU reset may correct the problem.

Why Aren’t Stock Intake Systems Designed as Well as Aftermarket Cold Air Intakes?

It’s not that factory stock cold air intakes aren’t designed as well as aftermarket cold air intakes. The thing to consider is the purpose for the design. The stock parts are designed with consideration for performance, efficiency and quietness. This often means a sacrifice in performance and efficiency for quietness. The thing is that people purchasing aftermarket parts don’t mind and most prefer some extra roar to their engine so they are able to get better performance, efficiency, and a little extra sound to their engine. Another thing that gets considered is that when new automobiles are tested, they are tested in air temperature controlled environments so the designers are not incentivized to focus on the parts’ performance mimicking natural conditions when the environment is hotter.

What are Air Bypass Valves?

An air bypass valve is a component that attaches to your intake which is designed to prevent water access to engine in the possible scenario of water coming into contact with your intake. Water coming into contact with an air intake is not an issue that arises with most drives but some drivers prefer to take proactive measures against hydrolocking.

Should I Upgrade My Intake or Exhaust?

This a very common question among younger enthusiasts who are considering modifying their very first project car. The truth is that you’re probably going to upgrade both so the choice is yours. One of the most fun parts of working on your car is the freedom to choose the order in which you upgrade. Make your choice, and enjoy.

Myths Surrounding Cold Air Intakes

You need to have your ECU tuned after installing a cold air intake.

While this a fine general rule of thumb, as most cars benefit from having an ECU tuning after the installation of a cold air intake, this in not necessarily true in all cases. Some ECUs can adapt just fine to the dynamic differences created by having a cold air intake installed.

A cold air intake can increase the power by 35 horsepower.

This is not true. Expect a horsepower gain of 5-10 horsepower after properly installing a cold air intake.

A cold air intake can cause an otherwise stock car to lose power.

This is absolutely true. Car manufacturers spend millions of dollars on engineering research. In some certain cases, a cold air intake can perform worse than the stock air box. This usually isn’t the case when the installation of the cold air intake is combined with an ECU tuning. Some examples of stock cars that typically perform worse after the installation of a cold air intake are Subarus and Mazda RX-7s. The reasons are that Subarus already have a highly efficient air intake system and RX-7s intake system is highly specialized for it’s engine.


There are many brands that make cold air intakes. I’m listing the most popular brands so that you have some ideas to start considering. Which one is best for you will depend on car’s make and model, as well as your goals.

  • K&N
  • AirRaid
  • AEM
  • Volant
  • Injen
  • Spectre

Should I Buy A Cold Air Intake?

Should you buy a cold air intake? The answer is that it depends, mainly on what you are looking to gain. If you are looking for a fun project, that looks cool, makes your car sound cool and gives a couple extra horsepower, a little bit extra torque, and a couple extra miles per gallon; then yes, a cold air intake is for you!

If you are someone that is looking for massive horsepower gains than you should probably skip cold air intakes and start considering forced air induction systems.


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