THIS SITE WAS *NOT* DESIGNED TO SCIENTIFICALLY DEBATE THE ADVANTAGES OR DISADVANTAGES OF THE K&N AIR FILTER DESIGN. IT SIMPLY IS INTENDED TO SHED MORE LIGHT ON THE THEORY AND APPLICATION

FRAM

THE STORY BEHIND THE K&N PRICIPLE
The increased visibility through the K&N filter results from the expanded pleats and gauze-like material allowing more light (and consequently, more air) to pass through the opacity of the specially oiled material. The oil (like water clinging to a screen door) traps the dirt as it passes by, and also resists the passage of water, thereby reducing the risk of engine damage in extreme conditions.  You're looking
thru the oil.

Other than the obvious benefits of being reusable, horsepower and fuel economy increases can be realized in direct respect to the application. Smaller, compact OEM airboxes with smaller filters will benefit more so than large, open filters when changing to a K&N. Higher volume consuming engines (large horsepower, small engine in

WIDER PLEATS
  LESS RESTRICTION   
    MORE AIRFLOW 
      OIL IMPREGNATED   
        WATER RESISTIVE
          HIGH FILTRATIVE MATERIAL
             WASHABLE 
               REUSABLE
                 BETTER SEALING FLANGES
                    REINFORCED CONSTRUCTION

heavy vehicle, towing, higher RPM's, racing, etc.) will also see more increases than low volume, "effortlessly-cruising" vehicles (large engine in lightweight vehicle, lower RPM's, slower speeds, etc.)

The actual filter shape and design can benefit also by K&N's unique design in some filters. Take for instance the Ford Modular motor application (4.6 & 5.4 Liter V-8) Their advantageous OEM cone shaped filter incorporates a restrictive dome at the leading edge of the filter, which fits snugly into the incoming air-tube to silence the air cleaner under power. K&N's replacement version eliminates this silencer baffle, therefore increasing airflow dramatically just by design, in addition to the advantages of the freer flowing materials used.

Cleaning intervals are usually similar to the standard paper filter, however, since the oil may dry out after extended periods, even though not necessarily dirty, a periodic quick re-oiling is certainly

cheap and easy insurance to further protect your investment. Since the K&N has more filtration area in the same space as a paper filter, the K&N will also flow more air than the paper, especially as both filters go though their life spans, and accumulates more and more dirty.  Since some of today's compact air filters can cost upwards of $20 for a one time-only usage, the K&N can pay for itself in just a few short cleanings.

The K&N is not magic, nor is it new… professional racers have been using the K&N for years in the harshest and most extreme conditions for decades… from the dust of the desert, to the trials of the military, and across the skies of the globe. There may be better filters out there, but not for the cost, size, simplicity and wide range of applications as the K&N.

FILTER FACTS
1979 Ford Pickup 460 Big Block V-8 212hp:  14" diameter x 3" tall round filter  =  131.9 Square Inches of Peripheral area
1998 Ford Pickup 460 Big Block V-8 230hp:  12" long x 5.25" wide flat-pad filter  =  63.0 Square Inches of Peripheral area

This shows that the modern, more compact filter has less than one half of the peripheral area to allow air to enter, than filters used  nearly two decades ago. This results in the filter needing increased maintenance, and freer flowing material to regain the lost facing area. Even though the filter peripheral is smaller, the active surface area difference can be even greater, due to more exposed material resulting in K&N's wider pleats.

FINAL THOUGHTS- FOAM FILTERS: Foam filters were not used in this comparison due to their inherent disadvantage of "sucking tight" when a suction is applied, therefore being one of the more restrictive filtration designs available. The foam filter's accelerated deterioration when repeatedly cleaned or exposed to water also makes it a lesser choice than even to many paper filters. A foam filter when wet, is nearly useless. There are "foam" pre-cleaner wraps designed to keep an open air filter element cleaner in extreme conditions that flow nicely. However, K&N's "Pre-Cleaner" wraps are not really made from foam, but rather an "extruded" plastic mesh with openly designed spaces in between strands. These "pre-cleaners" are intended to reduce cleanings of the K&N type filter without interfering with air flow.

If you are concerned about filtration and you'd like to do a 'backyard' test on a selection of filters, there is a simple way to get a better idea in a quick few minutes. Take the filter in question and place the hose of your shop-vac to the element, sealing the edges securely with duct tape. Inside the vac, remove the vacuum filter and place several layers of tape on the inside, adhesive side up. Turn the vacuum on and lightly sprinkle a predetermined amount of fine sand or dirt on the face of the filter element (dust from floor-dry or kitty litter is about the finest you will encounter). Any passing dirt will be stuck to the exposed tape in the vac. Carefully compare this to other samples you have tested. Be aware this does not test flow or actual filter effectiveness, but can give you just a little bit more info on the 'invisible' workings of your air filter, than you had before.

4-Wheel & Off-Road Center

766 Grand Avenue ~ Hartford, WI. 53027 ` (262)673-4077