Aftermarket air intake systems have become one of the most popular engine modifications available for late model cars and trucks. An easy question to ask is why are these so popular? After all, didn't engineers who work for your vehicle manufacturer spend years developing the best engine components available? Since power and fuel economy are major selling points these days, it's hard to imagine car companies not doing everything they can to maximize horsepower, miles per gallon, or both.
The truth is, typical air filtration systems on most OEM vehicles are designed as a compromise. And because of this, you are missing out on power and mileage that could easily be gained. In the scope of this article, we'll explain what aftermarket air intakes do, and why installing one in place of your factory air hose, filter, and air box makes good sense - even if your car is brand new. In fact, especially if it's brand new - because you'll have the most amount of time possible to enjoy the benefits.
Basically, an internal combustion engine is a large air pump. Air, containing mostly oxygen and nitrogen, is pumped into your engine's cylinders along with fuel during the intake stroke, compressed and burned during compression and power strokes respectively, then forced out as spent gases during the exhaust stroke. Any resistance to the free flow of gases during intake or exhaust strokes robs power from your engine, which is why aftermarket air intake systems, exhaust headers and less restrictive exhaust systems are common engine modifications.
Because aftermarket air intake systems are effective at reducing restriction, they reduce power-robbing pumping losses, and they enable your engine to take in more air. We'll explain how this additional air benefits your engine momentarily, but for now let's talk about restriction and how aftermarket systems eliminate it.
We'll revisit the word "compromise" that we used to describe factory air intake systems in an earlier paragraph. It's not that the engineers who created your car or truck didn't understand these basic principles, they had to take factors other than performance into account when air intake systems were designed. In order to reduce overall engine noise, the natural vacuuming whine of airflow is quieted by restrictive air baffles. While it may be hard for many of us to imagine the sweet music of additional air intake noise as something to complain about, most car buyers (including performance car enthusiasts) are perfectly happy to leave things stock.
We feel if those car buyers fully understood how aftermarket air intakes provide improvements, and how easily these assemblies bolt in place without major surgery, most folks would buy them - enthusiasts or not. Because while aftermarket air intakes provide additional power, their less restrictive nature also yields higher fuel economy when drivers go easy on the pedal.
Traditional flat panel air filters fitted as OEM equipment are designed to be as easy to replace as a light bulb. However, this dictates a smaller overall size - a factor that is a primary source of airflow restriction. To improve on this, most aftermarket air intake systems are equipped with larger, conical air filters that eliminate the need for the factory filter and the box that encases it (known as the "airbox"). While every manufacturer makes claims about the effectiveness of their OEM filter design and materials, the greater surface area of larger air filters part of an intake system will always lead to greater airflow and less restriction.
The other main source of restriction is the factory air intake tube. Most factory tubes make awkward bends and have sound baffles inside them, which may inhibit noise but restrict airflow. Aftermarket air intake tubes are usually constructed from mandrel-bent aluminum or molded polyethylene to ensure tubes have a consistent interior diameter in spots where they bend. While polyethylene has a slight advantage in that it can be molded asymmetrically, both types feature larger diameters and smoother bends than the OEM tubes for greater airflow all the way to the throttle body or turbocharger.
We've all heard the old hot-rodding mantra which dictates "there's no substitute for cubic inches". While performance tuners through the ages have agreed and disagreed on this expression meant as a reference to cylinder displacement, all of them agree it's valid when applied to cubic inches (or feet) of airflow. Why? Increased airflow allows your engine to burn more fuel without compromising the ideal air/fuel ratio. So when you decide to hit the throttle hard, that extra fuel translates into more power no matter how big or small your engine is. And it applies whether a motor is naturally-aspirated or boosted with a turbo or supercharger. More specifically, an engine operates most efficiently with a mixture of 14.7 parts air to one part fuel, which is known as the stoichiometric air/fuel ratio. More air and fuel (in the proper ratio) in the combustion process means a more forceful explosion driving the pistons, and more horsepower and torque.
Thankfully, electronic fuel injection systems on late model vehicles (especially those with MAF (Mass Air Flow) sensors) have no trouble compensating for the increased airflow that performance intakes provide. Engine Control computers react to the increased airflow by automatically upping fuel delivery to maintain the correct air/fuel mixture. However, if the MAF sensor on an older vehicle may be prone to confusion by the change in airflow rate, AEM's aluminum Electronically Tuned Air Intake System offers the unique distinction of having a built-in electronic module that communicates with your vehicle's mass airflow sensor to ensure it correctly senses any airflow rate. This way, a check engine warning light is avoided. If you're uncertain about your car or truck, we'd recommend checking with the vehicle manufacturer first.
The ability that aftermarket intake systems have to draw cooler air from outside the vehicle proves to be an advantage as well. While "cold air" and "ram air" air intake setups position the air filter in different places, they both draw air from locations further away from the engine itself. Whether that location may be behind a bumper-height air scoop or center grille, the air drawn in is cooler because it's drawn from outside, not from underneath the hot engine bay. The benefit of drawing in cooler air is that it's denser and packed with more oxygen - allowing more fuel to be burned evenly for increased power. In fact, engineers estimate for every 10 degrees cooler the air is, power increases by 1 percent. Additionally, conical-shaped air filters offer a wider scooping area that packs air together more densely as passages narrow. This creates denser airflow into the engine under all circumstances.
Since we offer too many air intake kits to mention every one in this article, we recommend looking through the Performance Air Intake section of our website when you have a block of time to enjoy comparing different offerings that are available. As you'll see in the picture above, it's possible to enter the year, make, and model of your vehicle in the beginning of your search so that our website automatically does the work of narrowing down which kits are offered for your ride. Browsing through what's available, you'll notice each kit features one main lead picture. These pictures are not fully indicative of the variations you'll find for each kit, because components vary from vehicle to vehicle. For example, a kit showing a cold air intake without a heat shield around the filter is often available with a heat shield, or even a complete airbox.
In closing, modern vehicles are electronic marvels, with variable valve timing and other complexities that make traditional hot-rodding mods like cam replacement impossible or beyond the scope of the average enthusiast. A higher level of tuning from the factory also makes computer-controlled engines hard to improve upon. When you consider those facts, it becomes clear that the pure simplicity and function of aftermarket air intake systems make them one the highest bang-for-your-buck performance purchases on the market today. Sometimes, there's just no substitute for simplicity.