Understanding Mustang Cold Air Intakes & Ram Air Intakes

The stock intake system was designed to be the quietest piece in the engine compartment. The air filter, air intake tubing, the mass air flow sensor, throttle body, and finally the intake manifold itself are all key areas on a stock engine that can be improved to allow more flow and free up more power. The location of the stock intake in the engine compartment means the Mustang isn’t running as efficiently as it could be. There's a number of ways you can upgrade your pony's intake system, so never fear. Ideally, when picking air inlet parts it is best to have each part slightly smaller than the other, to create a funnel effect and increase air velocity as the air approaches the intake manifold. Think of wind entering a canyon, it will speed up and become stronger as it passes through the channel between cliffs. The bare basics of intake science are as follows:

• Hot air is less dense than cold air and limits power
• Aftermarket filters are useable and cleanable while being more efficient than the stock filter
• Aftermarket tubes provide a more direct path for incoming air
• Cold air and ram air intakes are two options each with their own pros and cons
• Adding on a tune along with an intake will net more gains, but are not always necessary

If you’ve ever put your hand near a running or recently turned off engine, you know how hot they get. Now imagine that heat running through your stock air intake, into your engine, and through your exhaust pipes. Not a very nice picture, is it? The stock tube has a number of bends and turns, so the air doesn’t flow as freely as it could. The air itself is also heated by the engine which reduces its volume. The result is a less than ideal mixture in the combustion chamber. The further from maximum efficiency the mixture is, the bigger the decrease in power. The chemistry behind why your Mustang makes more power with colder, denser air is cold air is denser than warm air. This means more O2 (oxygen) molecules per volumetric unit of air to react and combust with the gasoline. Therefore, more power! Remember, bigger boom (combustion) is bigger power (high school chemistry can be useful! This surprised me too…).

Another factor often forgotten is what the actual inlet tubing is made of. The stock one is plastic while an aftermarket unit is usually metal. The difference is heat transfer and absorption properties of each material. The stock plastic one will absorb heat and transfer some of it to the air flowing through it, thus warming it up. Metal has a much higher heat capacity and will not transfer much, if any, heat to the air passing through the inlet tract. This is just another reason to consider upgrading to an aftermarket cold air intake.

Replacing your stock intake with an aftermarket cold air intake (CAI) will take care of heat and increase power by:

• Relocating the airbox from the engine compartment to the wheel well, so cooler air is being drawn in
• The larger intake tube increases the volume of air being drawn into the combustion chamber, which allows for a better burn. Better burn means more power
• The shape of the tube allows air to take a more direct route
• The air filter is higher quality and less restrictive

A cold air intake replaces the factory air box, opening it up and allowing it to suck in cooler air, through a larger diameter tube, allowing your Mustang to make a significant amount more power over stock.

Air Filter: Usually conical in shape, with grooves and folds. Some of the benefits of an aftermarket performance filter include:

• Although smaller than the factory filter, it has more surface area which allows air to be drawn in from every direction
• Most aftermarket filters are reusable, and only need cleaning every 30,000 to 50,000 miles. The stock air filter needs to be changed every 15,000 miles, and must be thrown away
• Aftermarket filters draw in a higher volume of clean, cool air. Expect more power, improved acceleration, and even better gas mileage

Intake Tubes

• Specially designed to straighten air flow as much as possible, while looking good in your engine compartment
• Aftermarket pipes are typically mandrel-bent so there is no crimping of the pipe diameter at the bend

The question on everyone's mind is how much horsepower you'll gain from swapping your stock intake for an aftermarket one. There are manufacturer's that will promise a gain of 15-20 hp, but that's a bit of a stretch. How much power you pick up comes down to what specific cold air intake you choose as well as if you tune your Mustang after the installation.

The typical power increase is 5-10 HP, but can be up to 15-20 HP in newer 5.0 motors.

Much like a cold air intake, a ram air intake (RAI) pulls in cooler air from outside the engine compartment. Unlike a CAI, though, the Ram Air on a Mustang uses a shorter tube, which causes the air to be pushed into the throttle body with much greater force. There is a larger volume of air which, in turn, leads to more engine power.

As you increase the speed of your Mustang, wind pressure is forced through the intake manifold and filter. It’s almost like having a turbocharger, but without the additional parts. The downside to the Ram Air is that it will not be very noticeable until you are traveling more than 35 miles per hour.

​Other than those differences, the Ram Air Intake is the same as a cold air intake. The power gains are also similar at a typical increase of 5 - 10 hp with a ram air intake.

Here is a quick pros & cons list to help you decide which is better for your mustang.

Ram Air Intake:

Also known as a Short ram intake. This type of intake uses the straightest possible tubing with a large filter with a heat shield to get the maximum airflow. Does not go into the fender well.

• Pros: Pulls in more air, usually cheaper due to less piping.
• Cons: Air pulled in is warm from the engine compartment.

Cold Air Intake:

Uses a curved pipe to go in and sometimes down the inside of the fender to pull in air that is not heated by the engine. Uses a smaller filter than a Ram Air Intake and will not pull in the same volume of air as the Ram Air Intake.

The design of the cold air intake relocates the air filter to the coldest part of the engine compartment or through the inner fender to the wheel well. This allows the intake to pull colder, denser air into the motor. By pulling the colder air, combustion efficiency is increased, and in turn, creates more power. An added benefit of the efficiency in some cases is increased fuel mileage (typically 1-2 mpg).

• Pros: Pulls in cold air for better combustion.
• Cons: Pulls in less air, usually more expensive. 

• 1987-2004 Mustangs - No tune is required, but strongly it is strongly recommended to maximize the performance.
• 2005+ Mustangs - Most will require a retune, but some are designed to be used without one. The intakes for the 2005+ Mustangs that do not require a retune will not achieve as much increased power as the ones that do. 

Some cold air intakes will require you to retune your Mustang while others will not. Generally speaking, you will gain more power when you pair your new intake with a custom tune. Having a tune written to account for and optimize every bit of air coming in through your intake will give you the most amount of power and the smoothest drivability. There are combo kits available that package a cold air intake and a tuner together. If you're not sure which tuner/intake combination to go with, relying on these bundles a good way to take the guesswork out of it.

The more modern Mustangs' engine line-up is pretty high tech. Not only mechanically, but even more so electronically. With a plethora of sensors monitoring every little detail, the data and algorithms being crunched every second are simply astounding. This makes the engine a very fine-tuned beast, sensitive to the smallest changes. Be it greater flow, a temperature difference, higher velocity air etc., the ECU needs to know about it. Without adjusting these parameters, the ECU may not take full advantage of the intake, leaving power on the table, or worse yet, could possibly lead the motor to run worse. Even the Ford Racing system comes with a Pro-Cal tuner to accommodate for the intake, just so you know this isn’t bogus!

For those of you concerned with fuel economy, custom tunes can also give you a slight 1-2 MPG bump over stock as well. Average gains for a modern (2015+) GT are around 25-30 rear wheel horsepower and 35-40 rear wheel torque. The EcoBoost will see around 40-45 horsepower and over 60 foot-pounds of torque!

The air filter is where everything begins. A dirty, clogged or otherwise deteriorated air filter can impact engine performance severely. A quick scrub of the old air filter can improve suction and throttle response. Yet better, a performance air intake is the preferred method to ensure a sufficient amount of airflow to the engine. Performance filters use special materials in their filters to reduce resistance, turbulence, maximize flow but not sacrifice filtering ability. Thus, all the harmful debris remains out of the combustion chamber while you’ll benefit from better throttle response and maybe even a few extra horses as well. Furthermore, many aftermarket performance filters are reusable, meaning you can clean them using a special cleaning agent and they will be as good as new. Buy once; use forever—definitely a worthwhile investment. But which of two options do you choose from?

Back in the day of classic, carbureted vehicles, oiled filters were much more dominant when compared to non-oiled counterparts. The difference is the methods of filtration. An oiled filter uses oil to catch potential contaminants from entering the combustion chamber. As a result, the oil must be reapplied every so often in order to properly dispose of the contaminants previously caught.

A non-oiled filter, on the other hand, is a result of improvements in technology. The non-oiled filter does not require any maintenance except for when the filter is substantially dirty and requires cleaning. Cleaning is primarily utilizing a cleaning agent or dishwashing soap and letting the filter hand dry.

Both filters function the same way, but oiled filters offer slightly better filtration for pollutants. Oiled filters typically cannot be reused due to they cannot be washed. From a big picture perspective, you will not really notice a difference between the two filters, but if you really care to keep all of the dirt and grime out of your engine, then an oiled filter is the way to go.

1. Remove air filter from intake tube by loosening clamps with a flat head screwdriver
2. Wash thoroughly with a hose, getting in every crevice
3. Allow filter to dry completely
4. Reinstall filter onto intake tube

Some filters may require you to apply a cleaning solvent before you wash it and depending on what kind of filter it is, you may need to apply an oil coating to it before reinstalling. It is best to check the manufacturer's website and consult forums on what is the best procedure for cleaning, but the process should not deviate too much from the above directions.

C.A.R.B. stands for California Air Resources Board, and this is the board of governance who decides what modifications are legal and are not legal for use on vehicles in a state that enforces C.A.R.B. compliance. These regulations only apply to parts that could potentially alter the emissions output of the vehicle. These parts include anything on the intake such as cold air intakes, throttle bodies, throttle body spacers, EGR spacers, intake manifolds, and forced induction. C.A.R.B. is a part of the California EPA (Environmental Protection Agency) which is tasked with enforcing air quality regulations in California. 

These regulations also apply to anything modifying the exhaust manifolds (putting short or long tube headers on), or the mid-pipe (putting an H or X-pipe on, or modifying or removing the factory catalytic converters in any way, shape, or form).  These regulations do not apply to any other parts such as styling or suspension; only to parts in the powertrain that could affect emissions output.

To see if a part is C.A.R.B. compliant, look for the C.A.R.B. EO number on the products page of the part you're interested in (i.e. CARB EO Number: D-269-28). If a part is C.A.R.B. compliant, it will also come with a sticker with its C.A.R.B. EO number. This sticker is of vital importance. You'll have to keep this stick either in the car, or stuck to the part that it pertains to in order to prove its legality.

EO stands for executive order. A C.A.R.B. EO number means it has been tested and approved by C.A.R.B. which allows for the approved part to be installed on a vehicle and still remain complaint to the state's regulations. Parts with a C.A.R.B. EO number are allowed to be legally installed and pass testing while intakes without C.A.R.B. EO numbers are not legal in the state of California.

If a part does not have a C.A.R.B. EO number, assume it's not legal for use in states that enforce C.A.R.B. compliance. When a part is not C.A.R.B. legal, not only will it not pass C.A.R.B. states' smog testing, if you get pulled over, the police can fine you and even go as far as to impound your Mustang indefinitely for using illegal parts on public roadways. Aftermarket parts without an EO# cannot be shipped to the state of California unless they are for an off-road application only.  

After upgrading the air intake, I would suggest upgrading from the stock, restrictive the throttle body next. The throttle body is the part that connects to the air intake and the intake manifold. This is also the part hooked up to the throttle linkage which controls a flap on the inside which is what allows air to enter the motor. An aftermarket throttle body can help you gain up to an additional 10 horsepower. The bigger the intake tubing, the more air that will flow into your motor and the more power you’ll make. Like installing a cold air intake, the way to get the most power of this upgrade is to get a tune for your Mustang.

Throttle body spacers bolt in-between the throttle body and the intake manifold. A little bit of power may be gained with this upgrade, but the major impact you’ll feel is your throttle response increasing. This is a perfect first mod for the Mustang owner who has a stock Mustang, or little experience working on their car. A throttle body spacer installs very easily, taking only about a half-hour and basic hand tools. It is also possible to gain better gas mileage after this upgrade and it adds a unique whistle sound to your intake because of the bore design which forces the air into your intake manifold.