Laboratory testing of K&N air filters
Anyone who has even a basic knowledge of combustion engines know that an air filter is responsible for ensuring supply to the engine as clean air for combustion to limit wear to the dust particles in the air. Logically, therefore, has an engine without the air filter has a much shorter life span than with air filters. If this is true, why we see so many engines, some very expensive racing engines, which are completely equipped even without an air filter? Which factor can be so important that it is above the power of the engine with purified air? The answer to these questions in a short word: air flow.
Maximum power and torque are in direct dependence on the amount of air that can be supplied to the suction side. In open systems is very conscious decision not to air filter and a more accomplished performance at the expense of engine life.
In long distance races often raises the engine wear to the fall of an open system gained more power, and for the repair of these engines significant cost. It is not hard to understand why a motor that comes without filter has a very short lifespan. The life of an engine without an air filter of course, depends greatly on the conditions under which is being driven. In dusty off-road conditions, the engine can be destroyed in no time. On the other hand, is a road vehicle that is not run under these conditions, is also not easily damaged? Even under ideal conditions, it is uneconomical to drive without air filter.
If we assume that normal engines that run on air filters, a life of more than 150,000 km, have engines without air filters are usually broken after only 60,000 km. Performance test of leading Formula 1 teams have proved that K&N Filters have no performance loss compared to an open system. On some vehicles, even a performance gain was measured, which was created by a less turbulent air.