Do K&N air filters really filter?

[Church]

Thought y'all might like to know this, I noticed a lot of talk on this board recently about K&N air filters. I used to think these filters were the best filters on the market but I have changed filters after seeing a lot of dirt getting by the K&N! (Yes it was oiled properly.) Not only have I noticed this on my Jeep but I am switching to an Amsoil filter on my 67 truck as well. A lot of Jeepers have noticed that K&N's are letting a lot of dirt get by the filter too. With that being said I have put my flamesuit on (zip). Here is a test that was performed by an independant laboratory.

Here's a more detailed test procedure and conclusive results covering AMSOIL vs. K&N and paper air filters according to the Industry Standard Society of Automotive Engineers (SAE) test standard SAE J726.

Your car's engine "inhales" air that is mixed with fuel for combustion. But air contains an incredible amount of suspended dirt - typically 400 tons of it in a cubic mile. Much of this is microscopic dirt, extremely abrasive, that can cause serious damage inside the engine. Consequently, an air filter is a

An air cleaner must not only trap as much grit as possible, but it should do so without "smothering" the engine, restricting its vital airflow. Thus the most desirable performance characteristics for an air cleaning device are high dirt-trapping efficiency, and minimal airflow restriction as the dirt accumulates.

The Society of Automotive Engineers Test Code J726 specifies the procedures, conditions, equipment, and report format which air filters can be uniformly compared. A standardized dust contaminant is introduced into a specially designed testing apparatus at a controlled rate. Most of the dust will be trapped in the filter undergoing the test; the remainder is captured in an "absolute filter".

The air pressure upstream and downstream of the test unit is monitored. The test terminates when the pressure differential causes a predetermined amount of fluid displacement on a water manometer. By quantifying and comparing weights, pressures, and elapsed time, the experimenter can determine a filters efficiency, capacity and airflow-based life expectancy.

Our J726 trials were conducted at an independent testing facility in the upper midwest. The tests compared Motorvator, K&N, Accel, Fram, and AMSOIL products. The results? AMSOIL proved vastly superior to the competitors' air cleaners as the only air filter to consistently score high marks in all three vital areas of airflow, efficiency and capacity.

The AMSOIL 2-Stage Air Filter traps airborne dust with 99% efficiency; it holds an incredible 281 grams of contaminant (that's over half a pound); and it outlasts the competition. It performs two to four times longer than the others. That's why AMSOIL can confidently recommend a 25,000 mile/1-year service life. And the 2-Stage is actually re-usable, with proper cleaning and re-oiling.

[nroden]

AMSoil does make some good stuff. My grandparents used to sell it.
I dunno if I would use their oil or not in an older engine because of leaks but I know it was good stuff.

[Reumster]

Not sure about the test and such, but I'm sure that K&N filters meet the regulations on filtering.

[Chevyc10!]

So what do you charge for the Amsoil? Just kidding...
Good info

[nroden]

I dont think my grandparents have but a few extra oil filters left and some 10w-40. I don't know that they sold air filters back then.

[Bamm]

Church- I recently read an article where a car mag did a side by side comparison on a bunch of filters and K & N didn't beat purolator for Horsepower gain, you're talkin' $60-70 vs $10. I will try to find the article on monday when I get back to work and maybe post a link or some scans of the article for everyone to read. I'm sure that a lot of you guys with K & N filters will be bashing the article, but the dyno don't lie. IMO K & N relies on the same premise that the "splitfire" plugs do- if you need to have a tune up and you install "splitfire plugs" you will see a "noticeable" difference. Well common sense should tell you that if you put new plugs, wires, filters and such in for the first time in 75,000 miles, you will see a difference even if it's regular autolite/purolator stuff you bought at wallyworld.......................JB

[Bamm]

Q: Do those fancy split tip sparkplugs really work?
A: No. Electricity follows the path of least resistance. It has nothing to do with a split tip or a fancy U groove! The sparkplug does one thing only. It acts as the grounding source for the ignition and that's it, period, end of story. The only difference with a sparkplug is that there is a gap in the current path. The size of the spark is dictated by the voltage and amperage output of your coil and the output of your coil is dictated by the saturation (dwell) time of your ignition system. You'll hear claims like, "it made more horsepower" or "I got better gas mileage". Well of course they did! Their engine needed a tune-up or they wouldn't have tried the new plugs in the first place! Any engine would get better gas mileage and more horsepower after a tune-up!

What split tipped plugs can do is promote pre-ignition and/or detonation. How? Try this, take a hanger and try to heat it up with a cigarette lighter. Oh yeah, it gets hot, but not hot enough to glow cherry red. Now take a paper clip and heat it up with the same lighter. It gets hotter faster and glows cherry red! It's simple, it takes less heat to heat-up smaller objects. What do you think those tiny little pieces of split tip electrodes are doing in your engine? Now add more compression and heat (a race engine) and they act like a dog gone glow plug... detonation... ka-boom! Just about in that order.

[minibike]

I read the same article in Hot Rod magazine about 4 or so months ago. The Purolator paper filter performed as good as all the high dollar ones. After they get packed off with debris, the paper ones don't do as well, but the particles are stopped as opposed to passing through.

[Bamm]

Yeah that is probably the same article. I will find out monday. I was one of the first in my group of friends to use the splitfire plugs and I did notice a difference when I put them in. Of course, I put them in my '93 Saturn SL2 that had about 75,000 miles on the original plugs. I know that there are a lot of people that swear by them, but they are usually everyday guys that noticed some change when they put them in their trucks, you usually don't see anybody racing them where it looks like it should help the most, unless they are sponsored by them. ..............................JB

[the-wreck]

This topic has some funny timing. Last week I was talking to a co-worker and we were talking about the truck I was re-working. She Your using Fram filters right and then went on to say she use to work for them. We got on the topic of K&N air filters and that I was going to use one. She said she had read a number of studies that showed KN filters filtered air very poorly and thier air flow was slightly better than a good paper filter. So the question is do I want clean air in my engine or slightly more performance. Im selling my 14 x 4 filter.

[Woody]

Very Interesting!!

I used to use and sell Amzoil oil and was always happy with their oils. I had a '87 Turbo V6 in a T-Type Regal and used the 10w-30. Back then (late '80's) there was only a few Syn. oils on the market. Well I bought a Amzoil Air Filter for the Buick. Now the Turbo V6 sucks a hell of a lot of air into it. The Amzoil Air Filter would not let enough air flow for the V6. Engine would run very rich and rough. Put back in a paper filter and it ran fine. The oil for the Amzoil filter is very sticky/tacky. I bet it does filter as good if not better than any other filter on the market. And it probably flows fine for normally asperated (non-turbo) engines. I ended up with a K&N filter in it. Yes it helped but it was after all a turbo and needed a lot of air flow.

[Church]

It all boils down to what you really want, Clean air or better performance. I would rather be filtering my air with a cheese cloth than a spaghetti strainer! hehe

[nroden]

I'd say keepin dirt out would be better in the long run that running a little bit better. I gotta get all the miles and use out of this truck that I can until I retire her and redo her for the second time. Then I hope to make it a show truck.

[Grim Reaper]

I have no problem with proof that it works better but that is very biased and does not provide the actual figures. Is this a 2 out of three test? how much did the amsoil beat the the K&N by. Are we talking 1% or 50%?
I'll give you an example. Here is one Mile Marker pulled on Warn. Here is this test.
http://www.winchtest.com/
Ok that makes you think the Mile Marker sound like the greatest winch on the market doesn't it? That's supose to be an unbiased winch test right?
I know several people who have owned them and all have hated them and all have gone to a warn electric. The test also does not duplicate the way 95% of the way people actually use the winch.
I went wheeling this weekend. Started raining and trails got slick as snot. I don't have a winch. My bud was in front of me and we had to winch about 250 feet. I hooked a tow strap to the front of my 75 GMC Jimmy that's pushing 5,500 or so pounds to the back of his 74 Landcruiser that weighes around 4300lb. Up the hill we went. that was with a Warn 8274. Rated 8,000lb. Fastest winch on the market and nobody will contest that, that knows anything about winches. I can gurantee the Mile marker could not do that. My bud had one on his 79 Bronco. got the truck stuck good. Stalls the mile marker. My bud with the 8274 lnes up on him and pulls him out. Gee.....that Milemarke is rated 10,000lb and stalled and the 8,000lb Warn pulled it out.
My point is tests like this can be misleading. If somebody like Consumer reports did the test I would have more faith in it (and actuall numbers would have been provided) but when the company that sells it contracts somebody else to to test their product I have a little less faith and I want to see the numbers before I will believe it.
As far as the filter goes....I have K&N's in everything I drive. I was packing a paper filter on the trail truck to the point the engine was not able to perform in as little as 3 days of trail riding. I have NEVER had that happen with the K&N. I go 6 months between cleanings and these filter better the dirtier they get. I have not found any indications of much getting past the filter that wouldn't get past a paper. The inside of my air cleaner is just as clean with the exception of some of the oil from the filter has left a residue. Now if the amsoil out performs the K&N...well like I said...amsoil say's the test shows they are better but did not provide the test documentation so the question is how much better?

[Bamm]

Reaper- The test that was done was done by Hot Rod magazine. I feel that they were a good neutral party because they advertise for many if not all of the filters tested. The tests were straight dyno pulls to determine HP increases. I have to find the magazine to remember all the info. When I find it I will scan it and post the article here. If I remember correctly the K & N did have a very slight HP advantage over the purolator, but not much at all. Especially when you compare a $60 filter to a $5.00. I do agree with you on the warn winches, they are the best hands down................................JB

[Church]

here is one test

[Church]

here is another
I ran a comparison of the K&N and the AMSOIL on the dyno and was surprised to find that the AMSOIL beat the K&N. I did not expect it. I have no doubt that the AMSOIL was a better air filter for filtering out dirt, but I was surprised it also made more power.

[Church]

and another
Here is another dyno run I did with the Split Second with the 3 inch MAF and 305 cc injectors. As you can see the AMSOIL air filter made more power then the drop in K&N again. That is two different comparison tests on two different dyno dates with different configurations. So for those of you that have your minds made up and do not want to be confused with the facts just keep your heads in the sand and ignore the hard data.

You will notice the difference in the first gear run. That was caused by excessive wheel spin and the tires breaking traction again during the shift with a loud CHIRP. It was a real attention getter around the dyno shop.

[Church]

here is another one too
Here's the info I have on air filter performance. Tests were done using
SAE J726C Test Method 5-best --> 1-worst

Oiled foam Paper Oil Bath Oiled Gauze
(AMSOIL, UNI) (K&N)

Large particle efficiency 5 5 5 4
Small particle efficiency 5 4 1 2
Airflow capacity 5 2 3 5
Dust holding capacity 4 2 5 2
Load up characteristic 4 1 5 1
Backfire characteristic 3 2 5 3
Cleanability 4 1 4 3

As you can see, K&Ns are great for airflow, which is what they were
designed for. Their original application was on racing engines, where
airflow is important and ultimate engine life was of little consern. They
are not as good at filtering as paper or oiled foam types.

Ed Hackett edh@maxey.unr.edu The Desert Research Institute
DoD #0200 WMTC BMWRA DIOC Reno, Nevada

[Dropt72Shortbed]

Originally posted by Bamm 24
Especially when you compare a $60 filter to a $5.00.

i dont know where you guys shop but the K&n filters i buy at peb boys, kragen or autozone average $40even. the regular paper filters go for $10-$15 depending on brand. this is around here, maybe the prices differ in your areas or others but i think saying $60-$5 is kinda stretching it, thats a $55 gap. any local parts stores around me theres only around a $25-$35 gap.

as for the hype about K&N filters packing the extra hp in there, i never believed it. the only reason i run a K&N is because its reusable and cleanable, ive cleaned the filter on my blazer twice since ive owned it in the last 1.5 years, if it wasnt a K&N id now be onto my 3rd filter which would be equal to the price of my one K&N.


now for the chart church posted. i never believe a graph or chart that lacks the numbers, a bar graph with no numbers shows you nothing, that one bar can be twice as big as another bar and yet the difference can be like .01% or something ridiculous. in other words graphs like that can be manipulated easily. as for the dyno charts, that i DO believe.

now my question is, where can i buy an amsoil air filter, they dont sell them anywhere here. and are they reusable and cleanable like K&Ns or do i have to keep forking out every time the old one gets too dirty

[Grim Reaper]

That's the sort of stuff I can buy. Cold hard numbers. The first post read very biased like it came from AMSoil but coming from a impartial source like Hot Rod I can accept it.
On that chart with the 1-5 rating. the last one is K&N right? and the first is amsoil?
If so I guess it's time to order one up for the trail truck. My bud in the club that sells it will be delighted LOL.
Church what was the vehicle used for the Dyno. The HP curves look forced induction. The MAF size comment also lead me to believe it's an amped up turbo car.

[Church]

The last two tests were conducted with a 96 4Runner equipped with, TRD Supercharger with the FMU, Edlebrock Headers, Borla Cat-back exhaust, Kenne-Bell Boost-A-Pump, and the stock MAF unless other wise indicated. All test were conducted by independant labs/ people. I agree the first one is not a real good chart. The filters are washable and resuable just like the K&N's are. They range from 20.00 up to about 50.00.
there are a lot of people selling on the web, I sell them as well. I know of no one that actually carries the filter in a brick/mortor type retail outlet.

[MikeB]

Church -- I didn't understand your 5-4-3-2-1 filter ratings. Which is the best at trapping small and large particles? I've always used K&Ns because I can clean them, they look cool, and I assumed they did a better job than paper filters. I don't buy their horsepower hype. It's right up there with Split Fire plug commercials. K&N's president should be ashamed.

Nor do I buy that Amsoil makes more HP than K&N. Maybe if both filters are severely undersized (like 10" X 2")and the engine is pulling through a lot of air volume per square inch, one filter may be less restrictive than the other, but not when I'm using a 4" tall 14" open element. John Lingenfelter, a major league engine builder, says a properly sized filter offers the same performance as using no filter.

[Dropt72Shortbed]

Originally posted by Church
I sell them as well. .

well i was interested in the amsoil filters after reading all this, but now im not sure how biased the info is.

[guypm]

Church,
How much would a 14" x 5"tall filter cost me delivered to the Houston area ?
Thanks, Guy