The more dirt, dust and abrasive debris that is removed from the air entering the engine, the more efficiently the engine will run and last longer. It makes sense that buying a higher quality air filter will greatly contribute to higher engine efficiency and longer engine life. You'll get about 1BHP more from a good quality filter, but unless you're the princess who slept in the pea, you won't notice. What better quality filters do have is that they take longer to clog, so they don't really give you more power, they're better at avoiding energy loss once you've driven a couple of thousand miles.
I paid good money for a K&N air filter for my old traveler, an 18-year-old Subaru 4-cylinder. After installation, I heard a pretty clean grunt noise from the engine when accelerating, but the idle and mileage and gasoline performance were the same. On the other hand, a K&N air filter installed on my Kawasaki Concours not only gave me that cold grunt noise when accelerating, but I noticed a smoother idle and a small, yes small, increase in top speed performance above 7,000 rpm. So there you go, I think they're worth the money and time spent cleaning them every few thousand miles if used in a performance application, but for a normal old car, the standard, cheap paper filter is the way to go.
Manufacturers typically install standard air filters in cars instead of performance air filters because of their prohibitive costs. Studies also suggest that, as a result of more efficient intake systems and air cleaner housings in today's cars, obtaining high-performance air filters may not improve your engine's performance to a large extent. In addition, by replacing standard air filters with standard filters on a regular basis, you can keep the engine air clean and free of debris. Your car's oil filter sifts dirt particles the same way a filter sieves ground coffee in a coffee maker.
It is a popular mistake to think that dirt particles in a car filter are filtered the same way as through a filter in a coffee maker - that's not how an oil filter works. The design of the media in an automotive oil filter forms a kind of labyrinth through which the fluid must “negotiate” its way. With careful engineering, a filter manufacturer like Purolator designs the media as a kind of labyrinth through which fluid will pass, but particles will not. The engine air filter does not have to be changed almost as often as an oil filter.
Most vehicle owners have heard of the need to change oil and filter at regular intervals, but few understand the value of changing their car's engine air filter. A vehicle ingests 10,000 gallons of air for every gallon of fuel it consumes - that's ten thousand times the volume of gasoline! Imagine if this unfiltered air contains all kinds of pollutants such as soot, dust and dirt - what damage could this cause to critical engine components and possibly cause cylinder wear? Over time, this can lead to major repairs or even needing a new engine - so it is so important to change your engine air filter at least as often as recommended by your vehicle manufacturer. However, if you are driving in particularly dusty conditions or off-road it's best to change your air filter more often - always follow your owner's manual when replacing your oil filter. Most of us drive short distances most of the time - this really requires us to follow a “severe” service program rather than “normal” service program.
The reason is that if your vehicle doesn't drive on the road for long distances, the oil doesn't have enough time to heat up enough for water, condensation and crude fuel to evaporate from the crankcase - over time this condensation builds up and can cause costly damage to internal engine parts. When it comes to filters, all types require unique media to work properly - nothing can be done about unpleasant odors on the road such as construction areas or farm country. Many motorists don't know that if their vehicle is 2001 model or newer it is probably equipped with cabin air filter - this device is designed to keep the air inside your car clean and free of dust, smoke and even unpleasant odors that enter through ventilation grilles even when windows are closed. Filtration is about capturing and retaining debris and contaminants that could otherwise cause gradual wear and tear or even catastrophic engine failure - it's easy to assume all oil filters are same but when it comes to filters brand name doesn't matter.
It's best to trust manufacturers who place their decades of reputation on design, construction and performance of components, materials and engineering that go unnoticed once assembled. Therefore motorists and do-it-yourselfers should rely on engines to filters manufactured by those who have pioneered innovations such as Purolator who invented first automotive oil filter, first full-flow oil filter and screw-on oil filter. Failure to replace dirty or clogged filter will affect efficiency of your car's heating and cooling system - poor efficiency can cause other problems such as loss of air.