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Air Filter Study !!!!!!!!!!&#3


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I found this information on the web for what it's worth, it has my mind changed about some of the top rated filter systems:


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 on 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 occurred 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 stubbornness 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..




Following up from the thread the other day about K&N air filters:


I've been doing some research about air filters and the differences, benefits and dissadvantages of Paper vs Cotton vs Foam filters.


In short: Best filtration system appears to be using a high-quality multi-stage foam filter, that also has a light applicaiton of foam filter oil on the outside. And that ITG makes the best ones.


What I found was that in all cases a high-quality, taken-care-of Foam filter will both outperform cotton and paper filters both from air flow and capturing dust particles.


I think that K%N now has a foam cover that goes over the stock filter they sell. I would like to hear any comments or others thoughts on this subject.

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Interesting. There is no doubt that oiled cotton gauze produces more HP however the argument here is engine wear and life. I don't want to sound like a know it all but I do Validations (IQ, PQ, OQ) for the pharmaceutical industry and many times it involves the use of HEPA filters for Class 100 cleanrooms for the formulation / sterile filling of drugs. The FDA requires a formal testing procedure that is outlined in the CFR. The auto industry is very similar IMO however does not require the testing group to consider all parameters like the Pharma industry does. Case in point:


1. Using the SAE J726Ca test method to evaluate new replacement products (and the 1989 appendix for emmission compliance) a filter is compared to the "stock" or subject "A". If the subject "A" says to be changed after every 5000 miles, so does the replacement product ("B"). The results are then compared. Unfortunately a K&N will filter best after it has undergone what is called "Depth Loading" (read about it on their website) after about 25,000 miles of typical driving. Obviously the comparison will never happen if the test was conducted as per the federal guidelines. In addition, the results are pre and post filter weight and pressure drop comparisons. Air moisture is not a concern for the EPA in their testing. Paper will pick up moisture and appear that it filtered "better" whereas a K&N will not do this well. Does this mean we should pre dirty our filters?...draw your own conclusions.


As for the article you posted. I see the same flaws in the testing as I stated above. In addition, I feel that the conclusions they drew based totally on the oil analysis has more flaws than the actual testing. Sample control, Obviously these conditions were very extreme if the filter couldn't last a day on the Cummins V-12. There are dirt bike pre filters made by K&N for this exact reason. They even make snow guards for snowmobilers. The following conditions were not investigated in their validation protocol:


1. Ambient temp and engine temp (thermal breakdown of internal components)

2. Air moisture content (paper filters will absorb moisture)

3. Duration of engine down time between use (cylandar wall corrosion-more metal by product in oil)

4. Hrs between oil changes, same oil filters used? (this introduces bias information into validation. We do not know the PQ validation on the filters)

5. How new were the test engines (brake in period-more wear)

6. Was there any EGR after the filter?

7. There are more however i need to get back to work... :cry:

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Agreed! Oiled cotton filters will not filter as good as paper until the element is saturated (with particles). A saturated K&N will filter as good as a typical "STOCK" filter. The small particles that do get through will just be vaporized anyway. Keep up with a good oil change schedule, run good gas and you will be fine. If the oil has those "excessive particles" in it after testing, they should be looking into the oil filter's efficency first. For our typical driving, you will not hurt the engine with a K&N.

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I am not even sure the K&N is better flowing than the stock paper air filter. My old round filter on my S-10 was a better match between paper and K&N surface area. But the paper air filter on the SS has 2-3 times the area of the K&N (more zig zags of filter element). So even though the paper is more restrictive than the oiled cotton, there is more area to spread the flow over, so they may be about the same.

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I've seen a lot of material concerning the pros and cons of K&N filters, but I have yet to see for myself certified tests of these claims (both pros and cons). I'd like to get a copy of the BMIRA tests that were done on K&N filters, just to see the results.


The following link has some of the results of those tests:



I have a '91 Silverado Standard Cab w/5.7L V8 that has ~150k miles on it and it's had a K&N installed since very early in its life - and it has had no engine troubles at all :thumbs:.


I recently put a K&N in my SS, which had about 1500 miles on it at the time.

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Wow. Finally an anti-K&N test!


I've disliked K&N's since I had one in my '00 S10. I ran it for some time, and was rather happy with it. Until I took off my whole intake system for some engine maintenance, and found a fine powdery sandy substance all through my intake tupe to the CPI/TB unit. :fume:


Never again...

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Until I took off my whole intake system for some engine maintenance, and found find powdery sandy substance all through my intake tupe to the CPI/TB unit.  :fume:


Never again...

I made a post a while back regarding this. I had engine trouble because the Mass-air wires would get coated with the substance you mentioned. K&N said it was from over oiling the filter. I took a Q-tip dipped in alcohol and GENTLY wiped the wires on the M/A. A noticeable difference. :chevy:


K&N Problems

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