For most cars, there is no need to purchase an aftermarket filter. If you're looking to do a lot more power, then you should be prepared to spend a lot more or be disappointed. Filters help your engine breathe better, but the gains are not something you can easily notice. One of the advantages of a high flow air filter is that unlike regular filters, it doesn't need to be changed every year.
All you have to do is clean it approximately every two years. This is because they don't clog as quickly or as easily, but they offer better airflow and better filtration of the air entering the engine. And if your engine gets more air, then it can perform better. In fact, a high flow air filter can increase your horsepower by about 3 to 5 HP and also increase your torque. At the same time, this can lead to higher fuel efficiency.
How? In some of the more expensive units, the filter comes with a cold air intake unit. It is installed to extract air from the outside of the car instead of the hot air used inside the engine compartment. Going back to science class, cold air is denser and therefore will burn better, thus improving your engine performance. Yes, aftermarket air filters work. But, don't expect a bunch of extra ponies to suddenly appear when you hit the accelerator.
See the video above for more information. Fitting a K&N high flow air filter is the easiest, most cost-effective and least technical way to increase engine performance.
K&N
filters are worthwhile, reusable, and come with a 10 year or 1 million mile warranty. One problem that has been observed is that, due to increased air intake, high-performance filters can expose the engine to more debris and contaminants. An engine does not run on gas alone, it needs air (oxygen) and, since fire cannot exist without the presence of oxygen, air and gas are equally important.When performing routine maintenance on your vehicle, one of the most overlooked aspects is the air filter. It really is that simple and that's why upgrading an engine's air filter is the easiest and most cost-effective modification a homeowner can make. Cotton allows much greater airflow than paper, more air, however, it risks allowing contaminants to enter, but K&N has it covered, they use their secret sauce: filter oil. While replacing only the OEM air filter with a K&N high flow filter will add power and increase acceleration, the biggest gains will come from installing a complete cold air intake system. In addition, some users say that oil sprayed on some of these types of filters also enters the air intake systems of engines. A number of aftermarket manufacturers sell engine intake air filters that they claim provide better airflow and, as a result, increase a car's power and acceleration.
The EPA did not find a significant loss in fuel economy from a clogged air filter, but it did find in a test of gasoline-powered vehicles that acceleration improved with a clean air filter. The trademarked red filter (usually conical in shape) on display or its kit may include a closed air box. It's a lot like a vacuum cleaner, when you notice a decrease in power; a dirty filter can be the cause because the air is literally pushed at the price of your vehicle's energy. One is the original air filter that came with the car after thousands of miles, the second is a new Subaru OEM filter, the third is a low-cost CarQuest replacement, and the final part is a K&N air filter. Many are designed to directly replace paper car air filters provided by vehicle manufacturers; other reusable designs are included in a more free-flowing air intake system that provides more fresh air to the engine.
Warm air is not as oxygen-dense as cold air and, as you may recall, the air-fuel ratio is very important when it comes to horse making. So if you're looking for an easy way to improve your car's performance without breaking your wallet or spending too much time on installation then an aftermarket K&N high flow air filter might be worth considering.