Paper filters are made from compressed fibers. The spaces between these fibers provide microscopic holes the air must pass through. One by one, these holes become plugged with dirt and dust particles. Once a hole becomes plugged, the air must find an alternate route through the medium. This process is known as surface loading. As the surface of the filter collects more dirt, its resistance to air flow increases because there are fewer and fewer holes left open and as restriction goes up, horsepower and fuel economy go down.
To meet minimum filtration standards, the paper must be thick and/or the fibers must be tightly compressed and dense. Therefore paper elements that provide adequate filtration are restrictive to air flow by design. Any paper element that could flow as much air as an equivalent K&N would not provide safe filtration. Additionally, as a paper filter becomes more and more clogged, the pressure inside the filter drops while the atmospheric air pressure (approximately 14.7 psi at sea level) outside the filter remains the same. It’s like using your lungs to draw the air out of a plastic milk bottle. When the pressure differential becomes too great, the bottle will collapse. The same thing could happen to your paper filter, although it is unlikely. What can happen could be just as severe. An excessively high pressure differential created by a restricted filter can literally pull dirt particles through the paper medium. In other words, the performance of a paper filter, i.e. air flow through the filter and its ability to protect your engine, DECREASES near the end of its service interval.
The K&N air filter is somewhat more complex. The unique design features multiple layers of oiled cotton fabric which captures the airborn dirt particles. These dirt particles cling to the fibers of the filter and actually become part of the filtering media. This process, known as depth loading, allows the K&N air filter to retain many times more dirt per square inch than a paper filter. The cotton fabric is sandwiched between pleated aluminum screen. Pleating increases surface area which in turn promotes additional air flow and prolongs service intervals. Pleating exposes five times the surface area compared to a flat element like foam.
The dirt particles collected on the surface of a K&N element have very little effect on air flow because there are no small holes to clog. Particles are stopped by layers of crisscrossed cotton fibers and held in suspension by the oil. As the filter begins to collect debris, an additional form of filter action begins to take place because air must first pass through the dirt particles trapped on the surface. That means the filtration efficiency of a K&N element actually increase as the filter collects dirt. Tests have shown a K&N E-1500 filter will flow 60 percent of its maximum flow capacity after 50,000 miles of street use. And, considering a new K&N flows at least 50% more than a comparable paper element, that same filter will provide all of the air the engine needs even after 50,000 miles.
Conversely, dirt trapped by a paper element will impregnate the fibers, which will impede air flow at a proportional rate. In other words, performance decreases dramatically as a paper element gets dirty. At the service interval, say 14,000 miles, air flow through a paper element can decrease as much as 70 percent.
The efficiency of K&N’s oiled cotton gauze medium has been proven time and time again. The condition of the filter can be monitored with a vacuum gauge. The vacuum reading increases as the filter nears its service interval. A high vacuum reading means the filter is dirty and needs to be serviced.
Stock Replacement Filters
For the service-minded consumer, utilizing the stock air filtration system is easiest so we manufacture exact replacement air filter elements to fit in place of the factory filter. Dimensions are held to minimum acceptable tolerances to insure a perfect fit inside the stock air box. Molded rubber sealing surfaces, edges and/or end caps combined with our unique pleated cotton gauze medium creates a filter that is so durable we warrant it for ONE MILLION MILES or 10 years. And, K&N original equipment replacement filters are emissions legal in all 50 states.
Street engines are exposed to the same risks as racing engines but for a longer period of time. In this application, a permanent, high performance air filtration system must be durable enough to last the lifetime of the vehicle as it travels through any and all driving conditions.
Getting back to air flow for a moment, we have discussed stock air filtration systems and why they compromise air flow. We have also explained how K&N’s unique design is less restrictive compared to a paper element. Installing a K&N Filtercharger in place of the original equipment or aftermarket paper filter removes the restriction which then allows the engine to inhale all of the air it can physically use. Increasing the amount of air available to the engine promotes performance since oxygen in the air is a necessary ingredient for combustion. If you have a computer controlled fuel injected car, the computer will automatically add the right amount of fuel to compensate for the additional air. If your engine is carbureted, more often than not, no adjustment will be necessary. However, for competitive motorsport, it may be necessary to re-calibrate the carburetor to achieve optimum performance.
The amount of performance gain varies from vehicle to vehicle. A small displacement four cylinder engine may only realize a two or three horsepower gain while it isn’t uncommon for a 350 cubic inch V-8 to gain 10 horsepower or more. The greater the restriction created by the stock paper element, the greater the performance gain when you switch to a K&N filter.
JASON ***
BRAND NEW K&N FILTERS FOR SALE!!! ***
1979 L-82 
