Generally speaking, you should replace the engine air filter every 12,000 to 15,000 miles. Check your vehicle's maintenance schedule in the owner's manual and follow the manufacturer's recommendations. If you drive on a lot of dirt roads or subject your car to high levels of stress, check your air filter more often than recommended by the factory. Volumetric Efficiency: Calculate the EV of your engine (here the volumetric efficiency).
Air filters stop silica and other solid contaminants by trapping particles in the fibers that make up the filter media. Most air filters are made of resin-treated cellulose (paper) that is combined with synthetic fibers. The typical paper air filter will trap most dirt particles that are 5 to 6 microns or larger in size, along with 80 to 90 percent of particles up to a couple of microns in size. Some of the best premium air filters will stop anything 2 microns or larger in size or larger, and most particles 1 to 4 microns in size.
The formula used in the calculation says that there should be one square inch of filter area for every 2.5 CFM of airflow. The goal of this 2.5 number is to have the absolute minimum restraint for a long period of time. Since it is usually located near the engine air cleaner, now is a good time to clean the mass air flow sensor. Low-cost, single-use standard filters typically last 12 to 15,000 miles under normal driving conditions and filter contaminants very efficiently.
Featured image of an air cleaner on a page containing a calculator that provides the air filter area required for a given power. You can also measure the inside diameter of your engine's air return frame to determine the correct size. Basically, the engine air filter helps your car breathe better by capturing pollutants in the air before they enter the engine and by allowing clean air to flow freely through it. On most newer fuel-injected vehicles, the air filter is located inside a rectangular box called a cold air collector box.
This calculator takes into account the filter life, when you give the filter size. This air filter calculator will tell you the approximate filter size you need for your engine power. This can be useful for comparing the exact sizes of the different filters and the difference between the two. For Audi and Porsche, the calculated required filter size is approximately twice the actual filter size.
If there is too much air volume after the MAF sensor, air may not move smoothly through the MAF sensor, which will cause idling problems. The OEMs recommended replacement interval for many air cleaners today ranges from 30,000 to 60,000 miles, but these ranges are for ideal operating conditions. This air cleaner size calculator includes some headroom to account for the reduced flow capacity of an air cleaner that has been used for some time. Washable and reusable, K&N air filters can go up to 50,000 before needing cleaning, and are so durable that they come with a million-mile limited warranty.
But more importantly, those filters were used to straighten and diffuse air before it entered the carburettors. If the factory air box receives a lot of dirty air, then the filter size may be larger to cope with the increased dirt it will be exposed to.