You know, if K&Ns filter is so great, how come they refuse to publish any information on their filtering efficiency. Furthermore, one can confirm the whole K&N myth by simply comparing the OEM cfm rating of the filter @ 1 psi versus the maximum theoretical CFM rating of the engine. In most cases (including the Aerostar 3.0L and 4.0L), the OEM filter will flow nearly twice the volume of air that the engine can theoritcally displace. In reality, the engines actual displacement under ideal circumstances is about 20% to 30% lower than the theoretical figure. So big deal if the K&N flows better, this fact is irrelevent. I have also done Google searches on the subject, and most of the material I found was either non-scientific, i.e. alleged performance gain that were not run on a dyno, and worse yet, were not run on a dyno with a conventional OEM filter in place, multiple modification were done, so you cannot attribute the gains tot he filter itself, etc. In addition, I found most of the studies that were "scientific" were funded by K&N or funded by teams that were sponsored by K&N.

Now if there are not some major flaws in K&Ns design, why do they refuse to post information like filtering efficiency at various micron ratings? Why do they recommend using their dust cover in extremely dusty environments? And how come both Volant and AFE have come out with filters playing on this filtering efficiency weakness? Yup, Volants new power core is claiming that it removes more finer particles than the conventional performance filter. In fact, they claim to meet OEM filtering standards and to last a very long time without any maintenance.

They also publish the fact that as the K&N becomes plugged, it begins to become less efficient at removing particles. This does stand to reason, since the more dirt the filter collects, the more the oil dries out, the less new dirt is attracted to the oil. Also old dirt and oil may start to come off.

AFEs new ProDry series also claims to have a higher filtering efficiency and they don't rely on oil to do the filtering at all. It is a true filter, and is made of a synthetic material than is fine enough that dirt and other particles can't go through it or embed themselves in it. This makes the larger filtering media really more for structure, while the synthetic film does the work. It also makes them much easier to clean, just rinse it off with water.

K&Ns claim to be the best is largely because they have the most money and the best lawyers, and nobody is willing to challenge them.

 

Great notes! All True. One idea that has not been touched. With most pleated filters, once you reach high efficiency, you loose high air flow. The more you filter, the slower the air flows!

When the pleated filter goes from 4 to 5 to 7 layers , then add a filter cover, you loose big air flow.

The Powercore has 4 times the filter media and only passes through 1 layer of media, not 7, plus a sock and still is more efficient!!! 99.98%

Throw that into the mix?

My 2 cents!

 

a high air flow filter is a waste on the Aero 4.0L which speeds 99% of it's life running below 3k rpm

filter blocking particle size is one of most important criteria for long engine life
Baja dirt racers care little about long engine life, the engines seldom see more than 2k before a total rebuild or new engine

 

I'll not put a K&N on my 'new' Aero. I'd not studied filters as much as I have now. I'd rather it be cleaner inside than more power now. Tho they flow the most they also let in more dirt. Live and learn.

* I'll just dump a lil nitro in the tank if I need mo power RIGHT??? *

 

BTW K&N do publish some info. They use the coarse dust at 5 microns which is too big for me. Thats the standard test dust most use. I want excellent filtering too so I'll go back to paper for now. Some oil wetted foam tests say they're superior even in particle removal, but I'm not convinced yet. Perhaps a combination filter would be best. Interesting, all this is..