The concept of high-performance air filters is that they provide a less restrictive air flow, allowing the engine to draw in more air and fuel, thus generating more power. But don't expect a huge difference in power when you hit the accelerator. The numbers are small and you may not even feel the extra power. However, they will still improve your performance.
The question often asked by skeptics is whether cone air filters actually work and the answer is yes. In fact, the best sports air filters can increase your horsepower between 3 and 5 HP and also increase your torque. It suggests that the increase in power could be the result of less filtering, although this aspect was not observed. Jason Fenske from Engineering Explained tested these claims and it turns out that yes, high-performance air filters do produce more power.
On the test bench, aftermarket filters produced more than the OEM unit, with the largest gains produced by the K&N filter (around four horsepower and five pounds). Fuel economy has also been improved because high-performance air filters draw air from outside the engine compartment, where the air is colder. This cooler air is denser than the warm air inside the engine compartment, which is heated by the internal combustion of the engine and other movement mechanisms that generate heat through friction. Replacing your air filter on a consistent basis can help you extend the life of your engine and preserve its original performance.
High-performance air filters are more technically known as high-flow air filters, which explains well what differentiates them from an average air filter. They don't clog as quickly or as easily because the filter has a larger surface area, but they offer better airflow and better filtration of the air entering the engine. While factory-installed air filters are primarily designed to prevent dirt from entering the engine, a well-performing air filter needs to find the perfect balance of filtration with airflow. Simply replacing the engine air filter can increase power and, in some cases, even improve mileage.
While the original new and dirty filters were almost identical in their sprints (9.01 seconds from 20 to 60 mph and 3.61 seconds from 45 to 60 mph), aftermarket air filters improved that performance.