How a Drop in Filter Increases Engine Performance
Aside from using a drop in filter, replacing your engine air filter regularly is imperative to maintaining your car and can add years and thousands of miles to your engine life. It also creates an atmosphere where your engine can run more efficiently and burn less gasoline, making both your wallet and the environment happier. Replacing your stock air filter with a high-performance drop in filter does all of these things as well as give a slight boost in engine performance and efficiency.
Engine Air Intake
The reasons for this increase in all things good, with little to no compromise, is based on a simple engine model. All engines are, in principal, large air pumps. Air goes in, air comes out. Simply put, the more air that goes in and out, the more power the engine makes. A performance air filter provides less resistance for the incoming air. In some cases, if well made, there's almost no resistance. This means the engine doesn't have to work as hard on the intake cycle and gets more fresh air. More fresh air means more oxygen. More oxygen means less fuel is required in the combustion stroke, and this provides more power and higher efficiency.
Drop in Filter vs. Alternatives
The benefits of a drop in performance filter over a cone filter, or a full cold air induction system, is mostly "drivability" related. Many new cars require the stock air box to function properly. And in some cases use the volume of the air box to determine mass air flow (which is how the car's computer calculates fuel delivery). With the use of a different intake system there may be required an ECU retune, a MAP-sensor or mass air flow sensor re-calibration. Many high-end intake manufacturers address these issues, but at an added cost. The installation of a performance drop-in filter will increase the performance of any engine over stock, and retains the stock drivability of the vehicle. It is a smart upgrade for anyone looking to get a little more power from their car, and even a bit more efficiency.