DML,
I have designed HEPA filtration systems for life support equipment. ALL of
the filters the I designed had elements that were
cellulosicfiber/glass/epoxy resin concoctions. The pore size for paper can
be MUCH smaller than any woven material. The smallest woven material pore
size that I encountered was around 30microns. HEPA captures 99.97% of
0.3micron particles, 2 orders of magnitude smaller! I use a K&N filter on
my Interceptor, but I dont drive off road with it. I keep it oiled well and
allow dirt/mung to build up on it and only re-oil per K&Ns reccomended
service interval. The oil will entrain impacted particles, and may reduce
the woven pore size somewhat, but it still cant compare as a particle
impingement filter with a well designed paper element, discounting pressure
drop. I would not Overclean a K&N and Im not sure if the K&N is the best
bet for heavy off road use (although all the off raod racers seem to use
them.) Then again, off road racers dont expect to get 200K miles on their
motors. Power vs. life...
Sorry about sounding off so much, especially when I dont really have the
answer...
Bruce
At 08:46 AM 7/21/98 -0800, you wrote:
>This was posted to the DML about a year ago, I've dug it out of my own info
>archive. I know many on the list use K&N's and clones so I thought I'd
>re-post it.
>
>>>>Subj: K & N filters
>
>John: I was
>responsible for evaluating re-usable air filters
>for a major construction/mining company that had
>hundreds of vehicles ranging from large earthmovers
>to pick-up trucks and salesmen's cars. This study
>was embarked upon due to the fact that we were
>spending upwards of $30,000 a MONTH on paper air
>filters. Using them one time then throwing them
>away.. I inititated the study in that I was convinced
>that a K&N type filter or oiled foam would save us
>many dollars per year in filter savings, man hour savings,
>and of course engines as these would filter
>dirt better than paper. (yes, I had read the K&N ads and was
>a believer)
>
>Representative test units were chosen to give us a
>broad spectrum from cars right through large front
>end loaders. With each unit we had a long history
>of oil analysis records so that changes would be
>trackable.
>
>Unfortunately, for me, every single unit having
>alternative re-usable air cleaners showed an immediate
>large jump in silicon (dirt) levels with corresponding
>major increases in wear metals. In one extreme
>case, a unit with a primary and secondary air cleaner,
>the secondary (small paper element) clogged
>before even one day's test run could be completed.
>This particular unit had a Cummins V-12 engine
>that had paper/paper one one bank and K&N/paper on
>the other bank; two completely independent
>induction systems. The conditions were EXACTLY
>duplicated for each bank yet the K&N allowed so
>much dirt to pass through that the small filter became
>clogged before lunch. The same outcome occured
>with oiled foams on this unit.
>
>We discontinued the tests on the large pieces almost
>immediately but continued with service trucks,
>formen's vehicles, and my own company car. Analysis
>results continued showing markedly increased
>wear rates for all the vehicles, mine included.
>Test concluded, switched back to paper/glass and all
>vehicles showed reduction back to near original levels
>of both wear metals and dirt. I continued with
>the K&N on my company car out of stubborness and at
>85,000 miles the Chevy 305 V-8 wheezed its
>last breath. The top end was sanded badly; bottom
>end was just fine. End of test.
>
>I must stress that EVERYONE involved in this test
>was hoping that alternative filters would work as
>everyone was sick about pulling out a perfectly good
>$85 air cleaner and throwing 4 of them away
>each week per machine...
>
>So, I strongly suggest that depending upon an
>individual's long term plan for their vehicles they simply
>run an oil analysis at least once to see that the
>K&N or whatever alternative air filter is indeed working
>IN THAT APPLICATION... It depends on a person's priorities.
>If you want performance then indeed the K&N is the
>way to go but at what cost???
>
>And no, I do not work for a paper or glass air
>filter manufacturing company nor do I have any affiliation
>with anything directly or indirectly that could
>benefit George Morrison as a result..
>
>******************************************************************
>
>--
>
>Tony J. Mastres
>Photographer
>Photographic Services __
>1120 Kerr HAll UCSB []_.-' (Q,___\
>Mastres@id.ucsb.edu *******`(o) >>>}__(o)s>
>
>
>
>
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