If you want to squeeze more horsepower out of your car, you probably know there’s quite a few ways to do it. But you want a quick and cheap one, you say? Look into getting a “Cold Air Intake.” You may have seen these devices, either on the internet or perhaps mounted in someone’s car. They usually look like a long plastic tube with a open-element air filter on one end. The idea is that you place the end with the  air filter under the hood off to the side where cooler air exists.

Why does cooler air make more power?

An internal combustion engine needs oxygen in the outside air to burn during the combustion cycle. (21 percent of atmospheric air is oxygen.)  As you will no doubt remember from your physics lessons, air expands as it heats up, which means hot air contains less oxygen than cold air. So, when cool air burns in an engine, more oxygen is available to burn with the gasoline so the engine produces more horsepower.

The problem is that most of the air under the hood of your typical car is quite a bit hotter than the air outside. In fact, it can be up to 50 degree F hotter! What cool air intakes are designed to do is pull fresh air from a cooler spot under the hood and feed it to the engine.

By the way, our car tech consultant at Alfa Romeo of Larchmont, a local Alfa Romeo dealer in Larchmont, NY, explained that his cool air phenomena is also the concept behind hood scoops. You don’t see them very often today (primarily for styling reasons) but their purpose is to draw air that is flowing outside into the engine. They also offer a second benefit. Because they sticking up right into outside air flow, they have a ram effect where the air is pushed under pressure into the engine’s intake system.

What’s the difference between an induction kit and an air filter?

When shopping for a cold air intake system you may come across “induction kits” and “performance air filters.” Here’s the difference. An induction kit comes with pipework that allows you to mount the air filter away from the hot engine. A performance air filter is just put in place of the stock factory airbox and sits in the engine bay. Or there is the other type, the “drop-in filter,” which is made of foam/gauze and sits in the air box, in the place of the standard paper version.

But do they work?

Although there is a lot of good marketing hype out there, it is important to realize that the power increase that you will gain from a cold air intake will be modest. On the other hand, it is an add-on that the installation is well within the expertise of the average DIYer. Costs are reasonable too. If you are looking for just a bit more power out of your engine, you may wish to consider a performance air filter or even a cold air induction system. There is one thing for sure, they certainly look neat on a performance car’s engine.