Paper filters are better than K&N-type for engine longevity

Oliver Hevvy

Precision Fit
Jun 21, 2013
628
San Francisco Bay Area, California
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Oliver
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K&N has done a great job of convincing people their filters are "better". They do flow more air per square inch than a pleated paper, OEM type.

But: they do not filter as well. More extra-fine dust gets in, and this increases cylinder and ring wear especially.

How do I know this? Back in the late 90s sometime, I got a copy of a detailed study run by a major heavy-equipment operator on filter effectiveness, change intervals, etc. When you own 500 bulldozers you care a lot about what filter is best and how often to change it. Their conclusion was that OEM type pleated paper filters better than anything else.

Want more proof? Go down to your local heavy equipment dealer and ask them what kinds of air filters they use. When you spend a quarter-million or more on a piece of equipment, you don't cut corners on a $2 part.

---

On vehicles I have with round air cleaners, I usually stack two of them to get more area and more flow, if the hood allows it.
 
CountryRoads

CountryRoads

Bigger Hammer
Oct 5, 2011
85
Salt Lake City
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Fred
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Hard to argue with that research, but I'm guessing someone will. ;-) Anyone want to argue that the oil baths are better?
 
edudley

edudley

Well Oiled
Mar 24, 2011
1,565
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Eric
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I second this article. I have tried the K & N only to find the throttle body and air intake parts really dirty. Cleaned the all up and re-installed the paper fitler and things have stayed clena for years.
 
slingshot

slingshot

Bigger Hammer
Oct 15, 2011
190
Abilene, TX
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Robbie
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Not disagreeing, but... I have ran K&N's for 30 years, on several vehicles have ran over 200k miles--never an engine problem. I also maintain them and change the engine oil/filter with synthetic or synthetic blend every 5k miles. Suspect if you run your motor in the same environment that bulldozers and heavy equipment run (i.e. dust and dirt clouds) a paper filter would be better. I run mine on paved roads and clean and re-oil my filters every 15k or so miles. Do not over oil--most people do. I will continue to run them...
 
Clyde

Clyde

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Nov 11, 2013
340
Arizona
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Clyde
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I do not disagree but I have no idea what the filter I am running is off of. It originally used a Purolator AFT1003-B filter. Needless to say this is a discontinued filter and I have been unable to find a replacement that will fit other than a K&N. So it is either that or an original oil bath filter I pulled off a parts truck. I guess I could modify the oil bath to use a paper element...

Here are some pictures of it before I cleaned and painted it. Anyone know a possible replacement paper filter?

20140112_125953.jpg20140112_130001.jpg20140112_130022.jpg20140112_130051.jpg
 

Oliver Hevvy

Precision Fit
Jun 21, 2013
628
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Oliver
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Old-style oil baths are not at all good. An old guy I knew, long dead now, told me that as a kid in the late 30s, he'd help his dad at a gas station. One of his jobs was to clean the inch or two of silt out of the bottom of an oil pan when a vehicle came in for service.....

I'd say, go to the auto parts store with your OB filter, and keep opening boxed til you find an element that fits....
 

Herk

Precision Fit
Dec 24, 2011
712
Boise, ID
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Nate
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I learned my lesson about using K&N filters on anything with a hot wire type Mass Airflow Sensor. Don't.
 
hawgcaller

hawgcaller

Bigger Hammer
May 27, 2014
100
Foothills of Ouachita Mountains
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Van
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I learned my lesson about the importance of good air filtration.

At one time, my thoughts on the use of air filters was primarily to keep bugs out of the engine and not much consideration of the dust involved. During a large part of my life, I did not see much of the dust that was floating around in the air that these engines engulf.
Many years ago I moved to the Midwest, and an area that had a constant wind blowing. A day of calm winds was a day that the wind only blew at approx. 10 mph constantly.
I started noticing a (red dust) in top of the engines of vehicles, that was something that I did not see at my home town.
I asked a technician, just what was that red stuff that was on all the engines. He informed me that it was DUST from the red dirt. Then came a Sunny day when we had all the shop door up enjoying the fresh air and sunshine. I looked out and I saw a red wall off on the horizon. When I asked someone what that was, they got busy pulling all the doors down and shutting all windows, getting prepared for the incoming Dust Storm. It was then that it dawned on me, of the importance of proper filtration for both Oil and Air.
It was then that it dawned on me, that what we needed to do was provide these engines with lots and lots of properly filtered Air, If we wanted to get more performance from them. The OE manufacturers, designed these systems, based on the knowledge that they have to warrantee these engines for a certain period of time. On a national level or on the world level in some instances, this could be economically catastrophic for the mfg. So they designed the filters to protect the engines for that reason.
The laws of physics will take care of the engine, if you adhere to physics.
If we want our engines to be able to breathe more, we modify our engines to be able to move more air, then increase the surface area with adequate filtration.
Any time a filter of the same size, claims that they flow more air, usually means that it does not filter as much. We have to be be careful, and use a compromise on airflow and filtration. I would bet on the side of filtration instead of improved airflow on a smaller airfilteration.
I have never been a convert to K&N, so I always have just taken 2 of the OE filter and stacked them is possible.
This has been my take on the air filter quality issue, yet a gospel for me, but not necessarily a gospel for others.
Have a great day.
 

Oliver Hevvy

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Jun 21, 2013
628
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Good story, Hawgcaller.

About four years ago, I had occasion to look at some research on how quickly solar panels get dirty, and why, and just what the dirt is. This gets studied because dirty panels make less juice. Skipping details, but even in cities, there is plenty of very fine dirt in the air, and it is mostly very fine sand-type material - quite abrasive.

Truly small particles don't hurts crankshaft bearings because they are so small they float in the space between the crank and the bearing. But rubbing surfaces, like piston rings and cam lobes, will wear somewhat quicker.
 

pavel6

Well Oiled
Sep 27, 2009
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I had a curious incident with my wife's LandRover Discovery some years back. I installed a K&N air filter thinking that might boost performance. A few months later we failed Aircare but I couldn't find anything wrong with the vehicle. Out of frustration, I went to a local "indie" shop (M&N Automotive here in Vancouver BC). The manager checked the fuel filler cap for leakage - there was none, checked over the vacuum lines and asked me what kind of air filter we were using... he installed a paper filter and we passed Aircare with flying colours. It is interesting that the computer threw no codes but apparently the change in the filter back to paper was enough to satisfy the exhaust sniffer.
You'd think the vehicle's ECU would have recognized any change in air flow (increase with K&N filter?) and adjusted the injectors at achieve a new equilibrium, but I guess that didn't happen. Live and learn.
 
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Oliver Hevvy

Precision Fit
Jun 21, 2013
628
San Francisco Bay Area, California
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Oliver
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Well, another poster mentioned problems with his MAF sensor. I know hot-wire anemometers are very sensitive to dirt. They're a good way to measure air flow; we used to use them in wind tunnels. But they are delicate....
 

Oliver Hevvy

Precision Fit
Jun 21, 2013
628
San Francisco Bay Area, California
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Oliver
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Layers of gauze soaked with oil. Usually held between two lays to screen. Lots of companies make them. You've almost certainly seen one, just didn't know it was a K&N type.

The theory is that dust, while trying to twist through the layers of cloth, hot an oily thread and stick. Most of them do. But not all.
 

Ken_Parkman

Sharpest Tool
Oct 28, 2013
390
Ontario
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Ken
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I've back to backed identical size (14 x4) open clean paper with a K & N on the dyno in several applications and found 9 - 12 hp in a typical mild ~300 hp V8. They do work for making more power.

Totally agree with they don't filter as good. Have heard there is something relatively new on the market that is trying to be the best of both worlds. Don't know any more about it.

So I do run a K & N in my performance oriented street toy, and it did help me achieve a performance goal. But I only drive that in good conditions, our environment here is good, and I try to stay away from dust, for whatever that's worth. I also ran one on the race car and everyone thought I was nuts; but the dyno testing showed it really did not hurt power over no filter. It was nice not to worry about ufo's in the hood scoop, and on freshening the engine looked excellent, noticably better than a buddy who did not run a filter. A K & N is way better than no filter.

But I would never use one in a dailly driver or something that is operated in even a slightly poor environment.
 
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