There are two main types of intake systems available for a car or truck. There is the short ram intake and the cold air intake. We always get the question of which is better, which makes more power, which is easier to install, and which sounds the best. Of course, this varies for every car and every different setup, but we'll tackle this question below and hopefully this article can help you better understand the differences between each setup, and the pros and cons to each as well.
Cold Air Intake
A cold air intake is designed to drawn in as much cold air as possible, giving it the name cold air intake. Some people also call it a cool air intake, because it's design is such that it places the air filter as far away from the heat of the engine as possible. A cold air intake usually is placed in the fender of a car, under one of the sides of the engine, or somewhere behind the engine depending on the engine design and fitment possibilities. Due to the intake having more piping, the cold air is usually more expensive, and more difficult to install. Part of the cost is also the research and development that goes into each intake to make sure that the intake performs properly. Since this intake has more piping length and bends, the manufacture needs to be sure that the air/fuel ratio remains in safe levels, which takes a lot of testing and development.
Another key take away is that since the air filter is farther away from the heat of the engine, your car is less likely to be affected when your radiator fan flips on. On some setups, the intake is near the radiator fan, so when the fan turns on and blows heat away from the radiator, it might blow the air right into your intake, causing poor performance.
Short Ram Intake
A short ram intake is the most popular type of intake on the market. This intake is designed to simply replace your factory intake with a new smooth pipe and an open element air filter. Due to this, the cost is less than a cold air, and also is much easier to install. Since the intake is in the same location as your factory intake system, it's design allows for engine heat to have an easier path into your intake system, creating less horsepower and torque than an equivalent cold air intake.
In the picture on the right, you see a short ram intake setup on a BMW M5. This car is a dual intake setup, so this particular intake kit comes with two pipes and two air filters. Some people also like the short ram intake better due to the looks of the kit since the air filters are in the engine bay.
Why doesn't my car have the option for a cold air intake?
When a manufacture builds an intake for a car, they typically test all available options. In their testing, sometimes the cold air intake either doesn't add more power over a short ram, or doesn't add enough to justify a price difference. In rare cases, a cold air might decrease power due to the maf sensor or another intake design that doesn't work well with your particular vehicle. In these cases, the manufacture will only have a short ram intake available.
Some intakes come with a heat shield. Is this worth it?
Absolutely. If a heat shield is available for your aftermarket intake system, we recommend to get it. Usually this allows a short ram intake to make more power, since it blocks off some engine heat from reaching your open element air filter.
I have seen intake scoops, do these help? How about ram air?
These help as long as the design is executed well. You'll see some race cars have intake scoops that scoop air from the bottom of the car, or the front of the bumper routing into the air filter. This allows more cool air to reach your air filter which creates more power. A ram air works about the same way. A true ram air forces air direct into your air filter, which gives your car more power since it essentially turns your intake into a cold air intake.
In the picture on the right, you can see how the air filters are surrounded by a shroud. When the hood closes, it seals this shroud, creating a blocked off ram intake.
Are short ram intakes with an air box worth it?
Some manufactures have intakes that include an aftermarket performance air box. This typically has much higher flow than the stock air box and allows your air filter to get more air. These are good for engine bays that don't allow for a heat shield, and have a problem of the radiator fan circulating hot air around the engine compartment.
What is heat soak?
Heat soak is when your intake piping becomes so hot, the piping heats up the air going into your engine, decreasing engine performance. A good intake system is built from material such as aluminum that doesn't allow the piping to get hot enough to hurt performance.
Why are some intakes so much cheaper than others? Is there really a difference?
Many people think that an intake is an intake, and you should get one that is cheap since they all perform the same. This is far from the truth. Over the years, we have seen many people use cheap short ram intakes or cheap cold air intakes that actually hurt horsepower. Their design is simply a pipe with a cheap filter, and since it has no testing, the design doesn't ensure that your air/fuel mixture remains in the proper range to allow your car to take advantage of the extra air flow, and instead this sends your computer into defense mode and it pulls back timing which hurts your performance.
A quality intake is more expensive because the manufacture invests lots of time and money to ensure that when you put the intake on your car, the design, size of the piping, length of the piping, thickness of the metal, and the quality of the air filter is good enough to put their name on it.
The air filter is a key component. It requires a good design because it's supposed to allow more air flow, but capture as much or more dirt from entering your engine. It's actually difficult to allow more air flow, but catch dust and dirt particles. Cheap intakes allow many more particles through that overtime can damage your engine, clog your sensors, and cause many other problems.
Why are some intakes smog legal but others are not?
Some manufactures make it an effort to have their intake tested by CARB (California Air Resources Board) to have it certified as smog legal. This is an expensive test, so not everyone does it. Smog legal intakes come with a sticker so that law enforcement knows your intake is smog legal, and you do not have a problem during smog time.
What is hydro-lock? Do I need an air-bypass valve?
Hydro lock is usually not an issue, but it can happen in some rare cases. Hydro-lock occurs when your cold air intake gets submerged in water, and your engine intakes water, causing engine damage. This can and has happened in the past, but it's usually an extreme case. An air bypass valve installs in the middle of your cold air intake, so if this happens to you, the higher pressure of the air coming into the air bypass valve wouldn't allow water to enter your engine. Some cold air intakes also convert into a short ram intake, so if you are worried about hydro-lock, we recommend to switch to a short ram intake during raining season or other conditions that may cause your air filter to be submerged in water, or water splashed up on your air filter.
I want a supercharger, turbo or nitrous. Which intake should I get now?
If you are going to go forced induction later, we recommend to wait on the intake. Just about every supercharger or turbo setup requires a different intake due to differences in the location of your throttle body, or other changes. A turbo setup is completely different, and you would need a special intake that comes with your turbo kit since it changes all of your intake plumbing and requires your intake to connect directly to the turbo. For a nitrous setup, it doesn't really matter, since usually the nitrous is plumbed right at the throttle body.
You can see from the picture on the right how the intake attaches directly to the turbo on a turbo setup.
So which one do you recommend? Which is better?
As you can see from this article, it's really up to what you are looking for out of your intake. A cold air typically makes more power, but costs more and is harder to install. A short ram is less expensive, easier to install, and sometimes creates less power. Some people prefer the looks of the short ram intake. Some people also like that the short ram intake is typically louder when you're heavy on the throttle. Whatever you choose, keep in mind to get a quality intake that sets the foundation for your other aftermarket modifications that will benefit from a good flowing intake system.