Smooth power everywhere

[Dakota_imp]

I'm pretty sure I am not missing the point. I agree, flow is very easy to measure. I gave an explanation of how very different the physics between the two types of filters are, and why that accounts for the greater flow of the K&N. This difference widens with engine rpm and HP output.

Here's a little image taken from a comprehensive test which clearly shows K&N having the least restriction to flow by a wide margin, compared to several others along with an OEM unit:



The K&N did pass more dust, but whether that would be significant with respect to any real difference in engine wear is not known, since K&N does in fact meet OEM specifications and warranty requirements.

A link to the entire test follows; the test is not favorable to replacing OEM with aftermarket and asserts, wrongly, that engines simply cannot take advantage of the extra airflow of the K&N/similar unless heavily modified. That's uninformed at best and really borders on the disingenuous. Certainly, a family car with a low-revving four-cylinder engine, such as a base-model Camry or Accord, will not get much out of a K&N, as it's not designed to make its power in the upper third of the tachometer. But our motorcycle is, and it can benefit from the increased flow, on both the intake and exhaust sides of the cylinder head.

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

From Baldwin Filters: Most engine manufacturers suggest a maximum allowable restriction between 15 and 20 inches of water (3.75 – 5.00 Kpa) for gas and LP engines , and from 20 to 30 inches of water (5.00 – 7.50 Kpa) for diesels. Exceeding these maximums will affect engine performance.

So, you think that a fraction of an inch water column "clearly shows K&N having the least restriction to flow by a wide margin" ?????

Your assertion that "and asserts, wrongly, that engines simply cannot take advantage of the extra airflow of the K&N/similar unless heavily modified." is still incorrect. Unless the existing air filter is a restriction, it won't matter if you put ten additional filters in parallel (KnN or OEM), it WON'T make a bit of a difference. The engine will be limited by its own volumetric efficiency; not the air filter.

Many years ago, there was a note on the European Cummins website indicating that customers should NOT use the KnN filter due to excessive wear (yes, I saw the website with my own eyes). This was enough for me to never use this type of filter.