My experiment with K&N.

[Old Smoky]

Shortly after buying my '92 Dodge-Cummins I bought a K&N air filter for it. I did notice a slight difference over the stock paper filter. What I also noticed was a thick coating of dust in my intercooler tubes, a dirty turbo, and a partially plugged intercooler after approximately 25,000 miles. I did not look at these things before I installed the K&N so I cant be sure all of this dirt resulted in the filter change (72,000 miles on pickup when purchased). After finding the dirt I changed back to the stock paper filter (brand new Wix). I didn’t really notice any seat-of-the-pants difference. After a few thousand miles my curiosity got to me and I pulled the intake ducting apart to see if more dirt had entered the system. Everything looked good. Just as clean as when I put it back together after cleaning it. I thought that it would be a good test to put the K&N back in since everything was clean, to see if it was the reason for the dust. I put everything back together with the K&N in this time, and dove another few thousand miles before rechecking. Well, I pulled everything apart this weekend and found more dust. Not as much as the first time, but there was defiantly a noticeable amount. Also, some oil from the K&N (I let it dry for about 5 hours before installation after cleaning).



Now this is not a real scientific experiment, but I think that its results show a fairly obvious conclusion. During both tests the vehicle was driven in the same arias with about the same number of miles on gravel roads, and I made sure that the filters sealed tightly to their housing. I am posting this merely to inform other users, not to try to convince one way or the other. I hope this is of some interest to the TDR community. I hope your experiences with K&N filters are better than mine.



Mike

 

[hdm48]

This is an ongoing topic. But let me say this. I build race motors for motorcycles and quads and quarter midgets and mini-sprints and so on. I build National winners not also rans. Unless there is some reason out of my control I always run K&N air filters. Why? Because they are simply the best there is. They are the next best thing to running without a filter at all. In fact, I have found more power with a K&N than without a filter.

BUT, if you have a stock engine with no mods to tax the intake system and no exhaust system mods you can run them for quite some time without serviceing. As soon as you start making changes you have to move up your service intervals. A diesel pulls air constantly unlike a gas engine and if you were to measure the total CFM in 20,000 miles you would find that a diesel will flow twice the air that a gas engine would.

A K&N will flow 75% or more than a paper filter and it does somthing that a paper filter can NEVER do. That is straighten out the air flow after the filter. straight air into your turbo is very important for power and total CFM. It will also [no mater what you've heard] filter out more particals than a dry paper filter.

But you must take care of it. service it sooner. It's cheap insurance.

I better get of my soap box now but I hope this helps.



--dave--

 

[Bob Beauchaine]

I've got to agree with hdm48. My intake system remains as clean as the day I first looked at it and my oil analysis supports the use of a K&N air filter. I have yet to have a bad engine oil analysis or an analysis that was not OK'ed for continued use. I have 2 K&N's so that I can quickly swap them at every other oil change (12,000 miles). I then clean, dry and re-oil the dirty one at my leasure. Just my . 02 worth.

Happy trails

Bob

 

[Lil' Dog]

Recent K&N Quality???

I am starting to think that the more recent products from K&N have started to be lesser quality than the older products.



I would like you to try an AFE filter on the same test to see what the difference is. . I would be curious. Again I have had my K&N on for about 4 years and have not had the same experience with dirt or oil. . Maybe the newer filters are not built the same way??



J-eh

 

[Bob Beauchaine]

Old Smokey

My last oil analysis was with a K&N installed in late August 2001 which was excellant. It was do to a young lady who fell asleep and ran a stop sign in a Nissan. I took the front end off the Nissan - there was over $6,000 damage to my '93. One of the things that had to be replaced was my K&N. I have to admit I didn't like the factory oil job so when I "swiss cheesed" my air box I re-oiled it.

Happy trails

Bob

 

[hdm48]

I think some of the problems that people are having with K&N filters are poor sealing and sucking the oil out of them. As we modify our rigs we are putting more of a demand on our intake systems and the filter is not being sized properly. As in not big enough.

Beleave me I have tried ALL of the other brands looking for an advantage. I have not found a filter that can beat the K&N for flow and removing particals. The biggest problem that we have in these trucks is finding enough room for a large enough filter. And when a person does find the room he/she ends up pulling in hot air from the engine compartment. But enough warm air is still better than not enough cold air.



--dave--

 

[Paychk]

I guess I'm a little slow or something, but I thought the 1st Gen air filter was sandwiched between the cover and back of the filter can, how does this allow the junk to make it past any filter? maybe I need to go out and reacquaint myself with my filter and housing?

 

[hdm48]

I guess that responce was too generic, sorry. In some of the 2nd gens they have a filter sealing problem. In our first gens it's the little seal at the back of the filter and all the hoses. The lack of oil is still an essue. And the K&N will let water through like it was not there at all. And one thing I forgot to mention. I have seen prople use oil that was NOT designed for K&N's on them. This is very bad. Never use any thing other than K&N filter oil or you will kill the filter. And NEVER, NEVER run it without oil or you will plug it up and it will never come clean.

I've run a K&N in my truck for about 50,000 miles and I have no dust or F. O. D. damage on my intake impeller. I just get more power and milage. I'm happy.



--dave--

 

[Old Smoky]

I wish I were as confident and satisfied as most everyone else using K&N filters. I don’t know if I just got a bad one or what. I have taken very good care of it and cleaned it as necessary, but not too much. An air filter is most efficient (about 99. 5%) just before it needs to be replaced, or cleaned as the case may be. I have checked and rechecked everything to be sure that the filter is on correctly, and that dust can’t be pulled in from anywhere else. It must be the K&N if everything was clean using the paper filter. I guess I could buy another K&N and try it to see if I have a bad filter. But it should be fine, and $70 is a lot to spend not being sure.



The paper filter works fine, but it could be better. Any other suggestions besides a BHAF? I sure as h_ll am not going to dust my engine for a few extra horses.



So, I remain unsure of what I should do. Again, I am not bad-mouthing K&N, and am not claiming that they make bad filters. I am just stating my findings.



Mike

 

[JIM S.]

I pretty much read all the K&N threads for informative purposess... . I think there must just plain and simplely be some bad filters out there. . . here is my experience. 6 years or so ago I put a K&N on my XR600 dirt bike and every time I take it off to clean its literly covered in dirt! but the tubeing after and the carb are always spotless! two years ago I got a RE 8008 (or whatever # it is) and its basicly the same story as my bike. I live in Moab UT. and its sandy and dusty so it an extream envirment, according to the K&N info. My inlet tube has a very light 'dust' if you will but that was there before and I never took the time to clean it to see if it came back... but the turbo fins have never been cleaner after 40,000 miles ..... Just my pennys worth.

Jim

 

[MikeO]

Guaze filters vs. foam vs. paper

While I will continue to search for the article I really want to post, please reference this.



http://www.bestsyntheticoil.com/amsoil/airfilters-technical.shtml



The article I am looking for (and thought I had) was performed by a mining operation in the west that operates several hundred diesel machines/vehicles. Their monthly budget for filters was something like $15,000. Anyway, their PM guy did an amazing comparison of K&N, oiled foam and paper air filters. The test looked at longevity (how long the filter took before hitting "X" inches of resistance), maintenance costs (throw away vs. service costs for K&N and foam), and efficacy (measured using oil analysis). The result? The paper won by a slight margin over the foam and the K&N came in way behind in total score. The only reason the paper won over the foam was because it was cheaper to throw it away than to have some $50/hour mechanic clean it, oil it and reinstall it. The paper was damn close to the foam on effectivenss but had a short service life.



I will update this post when I find the article.



Mike O.

 

[Old Smoky]

I have also heard about that same article. My diesel tech instructor pulled his K&N after reading about other tests like this. I might give the AMSOIL air filter a try. It sounds like a great filter.



Mike

 

[hdm48]

If I didn't say it before I will say it now. A K&N filter is a performance filter and cannot be ignored. In order to run one to it's potential you must find your service intervals. That can difer from one rig and inviroment to another. Using an industrial inviroment as a test for a pick-up aplication is total noncense. That's like using the shuttle as a test bed for car wax. Just like your engine oil changes you need to find the best time for filter service.

Like i said before, this is an ongoing topic.



--dave--

 

[Old Smoky]

hdm48,

I understand that the filter needs to be serviced regularly, and that testing in an adverse environment may not accurately show the filters performance. I have always taken very good care of my K&N. I check it at every oil change, and if it needs to be cleaned, I clean it. As for testing in an "industrial” environment: I drive my pickup many miles on gravel roads and live near many thousands of Acers of farmland that gets stirred into the air every summer. This may be too "extreme" of an environment for the K&N. Maybe I was expecting the filter to live in an environment where it wasn’t designed to operate. Whatever the case may be, the K&N is on its way to the landfill, and I am looking for alternative ways to increase CLEAN airflow. Thanks for everyone’s responses.



Mike

 

[Bart]

Morning Old Smokey, I too didn't like the oily film on the turbo vains. I cleaned and changed to a wix air filter. I noticed a drop in the fuel mileage (maybe it was do to winter time, I don't know). Did you experience a drop in fuel mileage? After cleaning the exstremely dirty K&N (from when I got the vehicle), I reinstalled it (in February) and noticed a very load turbo noise. It quited down after a while.

The wix filter I orginally installed had a piece of foam covering the paper element. Did yours? I thought that due to the double filtering element I was making the system work too hard to get air needed and that would explain the drop in fuel mileage.

I hear all these claims of 20 to 23 MPG, my best was 18 driving it the first time from Sacramento to Southern California. Now I get a normal 15-16 MPG. I run a 3500 12V'r 4x4 with an auto, 3. 54 & dualls #6 fuel plate 235x16 tires. I am an agressive driver, I try to run at 2K (72 MPH), but I think nothing of nailing it and smoking someone who's poking along. After installing the pyrometer I noticed the waste gate was frozen in the go position (I can boost 30-32 PSI). Maybe it explains the mileage difference. I tow various trailers, (biggest is 24' power boat). Vehicle has lots of "Huveos". but I have to be careful with the shifts. As far as I know it has a stock trans. After hooking up the trans temp gauge in the new (94 vintage) trans cooler line I noticed the temps run hot in traffic (full tilt on the 250 gauge) and 150 or so on the open road. I'm looking for a cooling fan that'll fit in front of the cooler.

Where am I going with all this rattling (no pun intended) I don't know. I just thought maybe someone may have similar experiences and have a little more knowledge about this BART (Big A&& Red Truck). John

 

[JIM S.]

how about a big oil bath air cleaner... my dads old home made garden tractor has one of those and after a summer of use the bottom of that thing would have an 3/4 to an inch of just plain sand! clean it out put "new" oil in it and ready to go agin!

Jim

 

[jjohn]

I used a K&N on a 95 Yukon Diesel. I took a trip about 100 mile's traveling on the Larime River road in Colorado (dirt... Very Dry dirt that day). When I got home I checked the Clean side of the air Box where there was a fine silt dusting you could write your name in.

Never used a K&N again. The filter was oiled properly and about 500 miles from last cleaning. I couldn't find a leak anywhere in the air box or ducting, and K&N supplys a well made rubber gasket for this GM application to seal it in good. It did breath better no question but?

 

[hdm48]

In a REALLY nasty sandy dirty icky area K&N makes a thing called a "pre-charger". What this is is a fine mesh cover to go on the outside of the filter. We use them in sand and very dusty areas. The only thing is it drops the CFM of the filter about 10%. Still better than a paper filter. I remember the days when we used to run nylons over our filters.

It's your choise what filter you run. I'm just trying to explain that the K&N is NOT a install and forget filter. If you want that, run the stock one.



--dave--

 

[Mgrant]

A few weeks ago, in desparation of needing more air, I purchased a K&N for my W250. Right away, I seen a jump in boost, lower EGTs, less smoke, and more throttle response. I've used K&Ns on my T-Bird and my F250 and I've had good success with both of them. I've even seen them used on recip airplanes, both natural aspirated and turbocharged. So, I figured that since the FAA certifies their use in aviation, I decided to give them a try for myself, even after hearing of everyone's complaints. Today, after about a 1000 miles, I took my intake hose off to see what affects on my intake duct and turbine blades, and you know, they were just as clean as they were when I put the K&N on. So, maybe some of us are experiencing a bad production. I've also have seen common mistakes of cleaning K&Ns; using compressed air, improper cleaning detergents/solvents, improper oiling, etc. I have learned from my own experience that I often had a tendancy to oil them before they are fully dried after cleaning, usually rushed by the need to use the vehicle. This caused the oil to attatch to the water instead of the cotton and get sucked out of the filter along with the water, leaving an unoiled filter. So, I usually let my filter to dry a full 24 hours before oiling, and let it sit for another day before use. Please share some cleaning techniques, perhaps we can see a pattern to what makes these K&Ns work or fail.



Rattle on!

Mike

 

[jjohn]

Hey Mike

I drove that 95 Yukon for 32K miles before buying my first Dodge CTD. In that 18 months the only time the air box was noticeably dirty was on the trip I mentioned above. Fine dry as a bone earth, no wind, You couldn’t follow another vehicle within 100 yards and still see where you going. I know this type condition is extreme. I can’t say for sure my filter was as dry as it should have been when I applied the oil, could have been part of it!

The aviation comment doesn’t mean much to me though because all the hours I flew I didn’t see many insects with oxygen masks at altitude, or follow another airplane kicking up a great deal of dust. (Just giving you a hard time) The only high demand filtration would be during take off and landing in most cases as dust particles are on the heavy side. If I flew dirt strips I don’t think I would use a K&N. It would however indicate it was constructed well, but I don’t think many would argue that. I wish I felt more comfortable trying one again as they certainly do breath better. If you bought two K&N's and kept one clean and dry ready to oil and install that would help with that dry time. What about some of those other Air systems anyone using another after market air system they feel good about.

JJ