REAL air filter testing. More proof that K&N is junk.

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http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
Let's see K&N passed MORE dirt/dust and plugged up faster than just about every other filter tested.

(Arlen) SPICER wrote,
"Now that I am not doing the tests and my objectivity is not necessary, let me explain my motivation. The reason I started this crusade was that I was seeing people spend a lot of money on aftermarket filters based on the word of a salesperson or based on the misleading, incomplete or outright deceiving information printed on boxes and in sales literature. Gentlemen and Ladies, Marketing and the lure of profit is VERY POWERFUL! It is amazing how many people believe that better airflow = more power! Unless you have modifications out the wazoo, a more porous filter will just dirty your oil! Some will say " I have used aftermarket brand X for XXX # years with no problems. The PROBLEM is you spent a chunk of change on a product that not only DID NOT increase your horsepower, but also let in a lot of dirt while doing it! Now how much is a lot? ANY MORE THAN NECESSARY is TOO MUCH!
Others are persuaded by the claims of aftermarket manufacturers that their filters filter dirt "better than any other filter on the market." Sounds very enticing. To small timers like you and me, spending $1500 to test a filter sounds like a lot. But if you were a filter manufacturer and you believed your filter could filter dirt better than any other media on the market, wouldn't you want to prove it? Guess what. Test your filter vs. the OE paper. It will cost you $3000 and for that price you will have the data that you can use in your advertisements. Your investment will be returned a thousand fold! EASIER than shooting fish in a barrel! So why don't these manufacturers do this? Hmmm? Probably not because they would feel guilty about taking more market share.
Now I am not saying that ALL aftermarket filters are useless. A paper filter does not do well if directly wetted or muddy. It may collapse. This is why many off-road filters are foam. It is a compromise between filtering efficiency and protection from a collapsed filter. Now how many of our trucks collapse their filters from mud and water? However, if a filter is using "better airflow" as their marketing tool, remember this....Does it flow better? At very high airflow volumes, probably. BUT, Our trucks CAN'T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give. And this remains true until the filter is dirty enough to trip the air filter life indicator. At that point performance will decline somewhat. Replace the filter and get on with it.
SURPRISE!!!
--
Steve Williams



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wrote:

I once found a site in Japanese where some creative street racers decided to test filters. They used a shop vac, a measured spoonful of copier toner, and what appeared to be coffee filters. As usual the K&N was near the bottom in filtering ability.
They were also quite worried about MAP sensor failures on oiled air filter equipped cars. Both K&N gauze type and oiled foam.
Its more extreme with a Diesel, as in the SPICER test above, but any reduction in restriction (K&N's claim to fame) is compensated by closing the throttle. Your engine requires one quantity of air per unit of work and this quantity is regulated by the sum of the throttle plate, air filter restriction, and other intake restrictions. Reduce restriction on one and increase it on another to maintain the same quantity of air. So unless your foot is pressed against the floorboard the air filter restriction doesn't matter.
With the HP race automakers want every cheap horse they can find. If air filters were as important for HP as K&N suggests then all an automaker has to do is increase the size of their paper air filters. Bigger paper filters flow the same volume with less restriction. Only example I know of is the huge Porsche 928 air filter.
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You are right the benefit of K/N is questionable. If it is that good, why doesn't car manufacturer install them in their car? As far as increase horsepower! all people have to do is to remove the air filter and try it out to see if they can tell an improvement. Replace the filter after the test run. My brother has purchased after market K/N cold air intake. We have tested the car with and without using G-Tech (accelerometer to test for acceleration). Test after tests, weather condition, road condition. There is no benefit. We did not test its filtration ability but sound the copier toner is a logical way to test.

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I wont defend K&N officially however, the comment that you dont need that extra air and wont benefit from it is ludicrous. More air, and cooler air, to a point will get you more power, maybe not enough to really notice.. 5-6 hp is probably about average. Why doesnt the dealer put it on, because it gives a bit more growl with that extra flow. add a CAI set up and you really increase noise. It all depends on the vehicle. My Discovery runs just fine with the factory filter and being that dirt is the issue on an offroad vehicle I would prefer to be safe rather than sorry. However, a conical filter (not K&N) on a high flow CAI set up produces noticible increase in high end power on every BMW I have put them on, plus the roar you get with the CAI/foam filter is awesome.
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I guess if the price is reasonable and you're not concern about if you actually gain 5 to 6 hp than install one. But paying over 100 dollars is bit too much for me. I wont say that I know a lot about engine breathing nor know how to tune the engine to get extra horsepower with just 100 or 200 dollars. I thought that to get extra horse power you need air + fuel then exhaust the burnt fuel out with less exhaust back pressure. So if that case, than improving air does not necessary improve overall engine performance. Ofcourse I am not talking about clog paper air filter either. We have to assume that the stock air filter is clean and is representable for this test. So change once per year is all you need for average driving condition. As far as CAI, once again not being the expert on this and since we are in discussion mode, most CAI I have seen is placed inside engine bay. There is no fresh air inlet from outside such as ramp-air to funnel the cold air in, do you still think there is a cold air benefit? Cold air is better for engine without question as it is more dense than warm air. I can see that if you change your air intake ports or opening your throttle body or MAF sensor to increase the cross sectional area plus air inlet from outside to get cooler air, then you will see a benefit. I have a Bonneville SSEi. I have removed the air filter, remove the MAF screen one day on open road to test the car. With the accelerometer, I took several readings and the results does not indicate with or without air filter to simulate an ideal filter (stock air box) that there is an improvement. We did the same test on Focus with Zetech engine but this time with full CAI cone kit couple with 2 inches aluminum pipe. Once again, the results is not conclusive. Perhaps my accelerometer measurement resolution and accuracy is questionable, but still the benefit between stock air filter vs CAI with K/N or what have you is still out there. Having said that, improve Hp does not come cheap with just K/N. I think there is more to it than that.

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200
then
either.
driving
is
in,
if
sensor
have
CAI
not
K/N
There are two ways to know for sure and only two ways. One take the beast to a shop with a dyno and put it on it, or two go to the drag strip and make a dozen runs with each set up and see what the average times are. Races are won and lost by margins less than a tenth of a second. 5-6 hp can be that difference. On partial throttle, your not going to see a major difference. Its when your toes are tickling the throttle plates the increased air flow comes into play. Whitelightning
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Check this link below to read other testimonials about K/N and its benefits/not so good. I thought it is interesting...
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/14121373/gotomsg/14799523.cfm

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Air + Fuel + Efficiency.
All other things being equil if you make the motor more efficient at burning gas and turning it into power you get more power. It takes work to creat the vacume that draws air in. Less intake restriction means more of the motors power can go to HP. That's why K&N and any other means of less restrictive air flow (and exaust from the push it out standpoint) increases HP and MPG. Double stacking a standard filter should do the same thing. I have to wonder why more people don't do that, or sell a kit...
As for why car makers don't do it, everthing they do is a balance between making what it takes to sell a car and making money on the cars they sell. You won't see a lot of tricks on stock cars because of that.
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Wrong.
Lets say you are cruising at 80 MPH in your gasoline land ark at 3,000 RPM. Note your throttle position with stock paper air filter. Now replace the filter with your choice of super non-restrictive filter and note your throttle position under the same conditions. It is closed more than previously because any and all restriction "saved" by the "performance" air filter is compensated for at the throttle body.
Don't bother to actually try the above as you would have to be able to measure the throttle position *very* accurately (the difference between stock filter and no filter isn't much.) And then average the results because under these conditions everything is always changing.
Under the stated conditions HP output remains constant. RPM remains constant. The quantity of air does not change. The engine will suck air on the intake exactly as hard with either filter. Look beyond the air filter, the only point "restriction" matters is that which is seen at the intake valves. K&N is happy if you only consider the restriction between the throttle and outside atmosphere.
The only thing which is important is the *sum* of the intake restriction. For a given HP output on a gasoline engine that sum will remain constant because it is the very thing which regulates HP output.
If the engine gets more air the fuel system will add more fuel to maintain combustion and emissions. More fuel = more HP = more faster, where the driver compensates by lifting on the throttle to reduce the air and therefore HP. The only time "less restriction" buys you anything is under full throttle.
The link which started this thread was specifically interested in air filter performance as related to Diesel engines. The intake equation is different as the Diesel does not have a throttle. More air could result in more efficiency.
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This make so much sense! thanks for sharing!
wrote:

burning
creat
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Diesel doesn't have a throttle, now that's the damnedest thing I ever heard. Whitelightning
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On Thu, 06 Jan 2005 01:44:38 GMT, "Whitelightning"

I was thinking the same thing. Diesel is injected, just like most modern gas engines. The main difference is ignition. It's like the dude was trying to imply gas engines still have the air and fuel mixed before entering the cylinders while diesels don't. Fact is, many modern gas engines dont mix until in the cylinders either.
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On Thu, 06 Jan 2005 02:26:20 GMT, snipped-for-privacy@ihatespam.net (SgtSilicon) wrote:

they're both injected, but that's about the total of their similarities. Gas engines still (with the exception of the Isuzu 3.5l Direct injection gasser) inject the fuel into the intake manifold, before the intake valve, whether it be at the throttlebody, like in a TBI system) or at the intake valve (SFI, CFI, MPFI systems). Diesels inject the fuel directly into the cylinder at extremely high pressures ( max injection pressure on a Duramax is 25,000PSI) at a precise time in the compresstion stroke to fire the cylinder. Gas engines are stoichiometric, i.e. they require between 12:1-14.7:1 air/fuel to operate. diesels are lean-burn... meaning they can idle at a 75:1-100:1 a/f mixture.
a diesels engine speed is controlled by the injection pump, there are no throttle blades of any kind. the pump controls the amount of fuel and the timing of the pulses. the more fuel the faster the engine runs, the available amount of air never changes. in a gas engine the more air is allowed in, the more fuel is added to maintain the A/F ratio, which increases engine speed.
-Bret
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Whitelightning wrote:

Why, it does not operate as a throttle. It actually is a pump. Kind regards, Erik-Jan.
http://www.fotograaf.com/trooper
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On Thu, 06 Jan 2005 01:44:38 GMT, "Whitelightning"

I think he's referring to a throttle plate (used to restrict air flow). Diesels regulate the fuel delivery & the only intake air restrictions are in place to minimize noise levels.
If 5-6 HP is the be all and end all, purchase & install good oil for your engine, tranny, & Diff. there have been independent studies that have measured a 5-8 HP at the wheel gain from that alone. PLUS. You'll save fuel & potentially increase the life of your mechanical parts.
For the best results? Sell your present car & purchase a more powerful car. Less monkeying around, better reliability, more power.
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If I understood that at least somewhat. Carborated vehicles might see a benift, but the ones with compuer controls will overide the filter benifits to keep the motor operating wthin spec. So you would need a tweak in the programming to realize the benifits?
wrote:

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I hate to break it to you Corey but: Those BMWs only SOUNDED faster..... :)
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WOW.
Once it got to a throw-away paper filter, I figured it would all be the same. I think I should look into finding an AC Delco that meets the size I've decided on for my beast!!
GMC Gremlin

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This is a very interesting study. It displays the AC Delco filter in almost the same light as others try to display the K&N filter.
Are there other studies out there like this? It is difficult to analyze one versus another. But if there were three different, unrelated surveys and they all pointed the same way . . .
Thinking twice about putting a K&N on my new vehicle. Maybe it belongs on eBay instead?
Paul P

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well power wise its more on a per engine basis than a lot of people here give credit. my cavy had a highly noticable increase in performance with a 10" round eldebrock muscle car filter set-up than with its original set-up... and then when i got too gutting that cat on that one is was a very even set-up ... not too much low and not too much high
Paul Proefrock wrote:

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