Calculating the right air filter area for your vehicle is essential for ensuring that your engine runs smoothly and efficiently. The formula used in the calculation states that there should be one square inch of filter area for every 2.5 CFM of airflow. This number is designed to provide the absolute minimum restraint for a long period of time. When it comes to determining the area sufficient for the required airflow, you can use the diameter of the air cleaner element.
To do this, measure the length and width (L x W) of the filter. If it is not square, use the smallest measurement first. For example, two 20 inch by 25 inch (500 square inch each) air filters should be used. It is important to note that filters should be changed every 30 to 90 days, depending on the type and efficiency of the filter.
This will not only make your HVAC system (heating, ventilation and air conditioning) more efficient, but will also keep the air inside your home cleaner and healthier. When calculating the filter size needed for a certain engine power, such as 400 bhp, you should multiply the calculated filter size by 0.4 or 0.3 to get a more accurate number. K&N tests have shown that for most two- and four-barrel carburettors, the airflow is greater when the diameter of the air cleaner is large compared to its height. For Audi and Porsche, the calculated required filter size is approximately twice the actual filter size. If your factory air box receives a lot of dirty air, then you may need a larger filter size to cope with this increased dirt exposure.
On the other hand, if you are using an average or restrictive duct, then you may be able to get away with a smaller filter size. If you are looking for a high-performance cone filter for your engine, you should consider what size you need for your engine power. If you have a flat air filter, enter its dimensions into a calculator to determine what size you need. If you are using a standard car air box, there is nothing you can do about its filter size; however, if you choose an aftermarket cone filter, you can select one that fits in your engine compartment. By following these steps and taking into account all of these factors, you can ensure that your vehicle has the right air filter area for optimal performance.