K&N filter efficiency

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I have heard mixed reviews on these filters. Some call them rock catchers while others swear by them. Isn't it just an oiled filter, similar to a pureone, Frams version (can't remember it's name) etc? What is the final verdict? Expensive gimmick or quality product? I had one of their synthetic blend media oil filters, but gave it away as a present. It seemed ok though.
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Every test I have seen where K&N air filters are tested for how much dust is passed, they fail miserably. They are only good for saving a minimal amount of funds, because they do not need to be replaced. But the work involved in cleaning them offsets that savings. There is no power to be gained by using one, in almost any vehicle built in the last 2 decades.

Truth be known if the cheap b&stard part appeals to you, it is actually possible to wash a good quality OEM type paper filter at least once......Not that I am recommending that.

If you are asking about the oil filters, I have no opinion.
 
K&N Air filters
I have used them in the past on vehicles that have compiled well over 200k miles. Not a single issue to report. Nor was washing and reoiling a chore. Are they the best at filtering? They are not. They do become more efficient as the miles pile on but they will never be as effective as a cellulose filter. I do feel there is a mob mentality when it comes to certain products being discussed here though. But hey, it's a forum.
 
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Independent test by South West Research Institute comparing K&N, AEM DryFlow, and AFE filters with all sorts of tech-speak and data comparisons for pressure drop, efficiency, etc:


http://autohifidiszkont.hu/bmw-tuning.hu/aemszuroteszt.pdf


AEM DryFlow was found to be the most efficient, best flow, least pressure drop, etc. Ironically, AEM is a wholly owned subsidiary of K&N.

I like the idea of a re-usable filter that you don't have to oil after cleaning, that out performs oiled filters in every aspect.
 
The regular paper air filter for my car costs $12 and lasts a minimum of 2 years [manual says 50,000mi]. K&N with the cleaning kit an oil costs about $75 and you must clean and re-oil every year. This process takes about an hour and then several hours of drying time. How on earth does anyone think this is cheaper?

Every test I have read says they are a poor filter.
I think they should be oiled at least twice a year.
Some people say that if over oiled, they can mess up your MAF sensor.
While drying the filter, after cleaning, you can't drive your car for hours.
While drying, doesn't the filter get dust on the intake side?
I certainly would not put one on a blowing heat vent in my house. That would load it up with dust.

IMO they have a place in very dusty conditions,off road vehicles.
 
Originally Posted By: WobblyElvis
The regular paper air filter for my car costs $12 and lasts a minimum of 2 years [manual says 50,000mi]. K&N with the cleaning kit an oil costs about $75 and you must clean and re-oil every year. This process takes about an hour and then several hours of drying time. How on earth does anyone think this is cheaper?


At that price disparity, i would agree. OEM for me are $22, after market cellulose are $12 and K&N are $45 w/oil. (Current vehicles)
 
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I'm definitely going to stick with the pureone oiled filter. It is amazing how much sand it is able to catch from the air down here on the coast. I have just heard so much discussion about them lately I wanted to see what the differences were between a K&N and other oiled air filters. I change mine out every other oil change, so a K&N is way too pricey for my taste.
 
I have posted this I don't know how may times, and nobody ever acknowledges it. I did UOA with K&N panel filter in my old 2005 Dodge. Silicon lower than average. If you keep your factory airbox and don't run an exposed cone filter, the air slows down a bit and many particles drop out of suspension (picture all the [censored] at the bottom of a factory airbox). They make a little more power at WOT. I like them. Some don't.
 
I think the problem is for what they actually are vs. what they claim they are, the filters are way overpriced.

You gain practically nothing in HP while losing some filter efficiency and paying 10x the price of a normal filter. Makes no sense.
 
Engine damage from excessive silicone material (the K&N Air Filter lets in) isn't worth it in the long-run!

In the short-term, a K&N Air Filter allows more air to move past the Mass Air Flow (MAF) Sensor creating more power at the expense of reduced engine longevity from dirty air particles wearing out key engine components faster than normal.
 
Originally Posted By: Shannow
member ran some very good tests a while ago, and they are at the front of BITOG,

http://www.bobistheoilguy.com/airfilter/airtest1.htm


According to the test,

"...I always heard on the 'net that paper filters best. It does, but it isn't as superior as I thought it would be. The K&N doesn't filter nearly as bad as the horror stories say..."


"...I figured the Amsoil filter probably would filter better. At best, it is just as good as the K&N. According to the photos it is slightly worse..."


"...For one, there is very little pressure drop across any air filter, and the difference between the best (K&N) and worst (paper) is very small. Yes as total power output increases, air flow increases, and differential pressure would also increase. So a K&N probably does yield some power on higher output race motors where every last ounce of power must be squeezed out. On lower powered street cars, it is probably not much of an improvement over paper. Basically, an air filter is first and foremost a filter, and should be chosen for it's filtration ability. I know after this enlightening experiment, that is exactly how I will select my air filters. Also remember, that this total differential pressure is measured from the atmosphere via the stock Miata air intake tube, airbox, accross the filter, though the test port, about 6 feet of tygon tubing and the manometer and back to the atmosphere. This is not the pressure drop across the filter itself. I may do a quick test with no filter ( I really hate to do it, but might anyway) to get a good estimate of how much is the system itself sans the filter.

Also bear in mind the K&N is cotton gauze, the Racing Beat is a single stage foam type filter, the Jackson Racing and Amsoil are dual stage foam, and the Napa is a paper filter. So cotton gauze does flow more air than foam as claimed. Amsoil is the best foam filter for flow. The foam filters are a real pain in the rump to service (this just my opinion and not fact). For that reason, I will never ever own a foam filter myself. I've owned several K&Ns and they are easier to service. If you are buying a high performance filter for airflow, K&N is tops in this test..."
 
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Originally Posted By: jk_636
I have heard mixed reviews on these filters. Some call them rock catchers while others swear by them. Isn't it just an oiled filter, similar to a pureone, Frams version (can't remember it's name) etc? What is the final verdict? Expensive gimmick or quality product? I had one of their synthetic blend media oil filters, but gave it away as a present. It seemed ok though.
confused.gif



If you want quality synthetic, reusable air filters stick to AFE or AEM. Avoid K&N. They are not good "filters."
 
I don't care about the reusable aspect. I just want to know why people like / dislike them. You said they arent good filters. Why is that? Keep in mind, there is no CAI on my vehicle, I am referring to a plain old everyday K&N panel filter.
 
Originally Posted By: jk_636
I don't care about the reusable aspect. I just want to know why people like / dislike them. You said they arent good filters. Why is that? Keep in mind, there is no CAI on my vehicle, I am referring to a plain old everyday K&N panel filter.


Many will point to UOA where Si is elevated and the vehicle was fitted with a panel K&N filter for that OCi.
 
Originally Posted By: WobblyElvis
The regular paper air filter for my car costs $12 and lasts a minimum of 2 years [manual says 50,000mi]. K&N with the cleaning kit an oil costs about $75 and you must clean and re-oil every year. This process takes about an hour and then several hours of drying time. How on earth does anyone think this is cheaper?

Every test I have read says they are a poor filter.
I think they should be oiled at least twice a year.
Some people say that if over oiled, they can mess up your MAF sensor.
While drying the filter, after cleaning, you can't drive your car for hours.
While drying, doesn't the filter get dust on the intake side?
I certainly would not put one on a blowing heat vent in my house. That would load it up with dust.

IMO they have a place in very dusty conditions,off road vehicles.


Who says you must clean and reoil them every year?
 
Originally Posted By: LoneRanger
Don't use an oiled filter in front of a Mass Air Flow sensor. Period.


My oiled P1 filter is a long way from my MAF sensor. There is quite a bit of duct work between the two.
 
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