Pros and Cons on K&N Air Filter

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Re: Pros and Cons on K&N Air Filter

Post by wyowillys46 » Wed Jan 24, 2018 2:34 pm

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Here’s multiple filters using ISO test procedures. Nice to have quantitative data.
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Re: Pros and Cons on K&N Air Filter

Post by Mr Wazzock » Wed Jan 24, 2018 3:03 pm

Image

Image


I seem to remember reading (years ago) that the K&N being originally developed for grasstrack racing and suchlike, in which case you might be expected to change/ clean more often than if for road use, where for the latter longevity (aka mileage) is much more important. In motorsport, you wouldn't mind changing/w@$#ing after every session/race meet, as part & parcel of other servicing between competitions.

:?:

I like the bit "It is amazing how many people believe that better airflow = more power" :D


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Re: Pros and Cons on K&N Air Filter

Post by hotflash44 » Wed Jan 24, 2018 3:24 pm

must remember that a internal combustion engine is basically a( air pump), with a explosion every 4th cycle. fact as i have been told is the better the air comes in and gets out the more HP is developed I.E. 871/671 blower. :cheers:
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Re: Pros and Cons on K&N Air Filter

Post by Mr Wazzock » Wed Jan 24, 2018 3:27 pm

Until you reach the upper limit of efficiency, then it rolls off.

I think what he's saying is the stock filter should be able to deliver all the engine can use, + some margin.

EDIT: sorry just saw the word 'blower', well I think this was about normally aspirated. :D


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Re: Pros and Cons on K&N Air Filter

Post by hotflash44 » Wed Jan 24, 2018 4:54 pm

Mr Wazzock, that okay, just said blower to mean lots of air, not a super charged Ural (can you imagine poor crank!) your right the engine like a Ural can only use so much air,if you over do it its wasted. think i would stay with the paper cleaner unless i was in very dusty/dirty conditions a lot. :cheers:
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Re: Pros and Cons on K&N Air Filter

Post by Red Dwarf » Wed Jan 24, 2018 5:57 pm

hotflash44 wrote:...your right the engine like a Ural can only use so much air,if you over do it its wasted. think i would stay with the paper cleaner unless i was in very dusty/dirty conditions a lot.
The amount of air a normally aspirated engine can pump depends on its volumetric efficiency, which is improved by a low-restriction filter and/or exhaust.
I travel in a--usually--low dust environment so I've had the luxury of experimenting with stock oiled filter, paper filters and a K&N intended for Moto Guzzi applications.

I found paper filters intended for mowers too restricting. Mine had less surface area than the factory filters.
My 750 seems happiest with the big Guzzi filter [and oversized housing].
Even a small increase in torque helps and servicing the filter is much easier than the factory version.

I keep a Unifilter sleeve in the trunk to slip over the K&N for dusty roads.
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Re: Pros and Cons on K&N Air Filter

Post by propwash » Wed Jan 24, 2018 6:48 pm

I have found it has become much more difficult to get quality Dnepr filters here in the USA. We have ordered a number of different times from differing countries and the paper filters that eventually arrive are of very poor quality. So poor, I refuse to use them. Many times the adhesive is brittle and flaking off.
K&N has a filter that fits.

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Re: Pros and Cons on K&N Air Filter

Post by hotflash44 » Wed Jan 24, 2018 7:21 pm

im not against K&n filters, have used them before, i like the ability to reuse and clean/oil the filter. back in the day 1969 about in the flat track days,we all used a filter called a Filtron it was a foam sock that was oiled and stretched over a wire screen then clamped to the carb. we could clean/re-oil during the race period as the tracks were oiled surface many times. :cheers: P.S. wonder if anyone has tried the individual style filter on a Ural instead of the central box type?
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Re: Pros and Cons on K&N Air Filter

Post by Snakeoil » Wed Jan 24, 2018 7:42 pm

I was going to just lurk on this one, but thought I'd add a few points. First, thanks for posting the link on the testing. I only scanned the first few sentences, but suspect it will make the necessary points very clearly.

In order for a filter of the same size as a paper element to flow more air, it has to do one simple thing, increase the flow area. You can't put more air thru the same area if all other things remain the same. So, if the K&N is the same size as an paper element, the only way it can flow more air than the paper element is to have larger pores in the media. Larger ports means larger dirt particles or even MORE dirt. It's that simple.

The marketing point that K&N makes about it filtering better as it gets dirty is laughable. Of course it filters better. The dirt is adhering to the oil and plugging up those big pores. What they forget to mention is that as it filters better (and better mean better than when first installed and clean) it also flows LESS.

K&N is one of the great snakeoil successes in our time. It never fails to amuse when I read the arguments for K&N. They are overpriced gauze filters. Anyone with gray hair that rode Brit bikes back in the day will remember that they came with gauze filters from the factory. First thing you did was throw them away and get a paper element.

I do own two K&N filters. One is on my Miata because it was the only element I could get for my cold air intake. The other is on my Ural because it was there when I bought the bike. I have a paper element I'm going to try this summer. Cheap element used on a lot of garden tractors. I think it was $6.00. Well made.

To the point Ron made, they probably are fine for street use. Desert use might be setting your engine up for premature wear due to the copious amounts of dust.

And to the point made by someone here, yup, K&N threads are right up there with oil threads.
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Re: Pros and Cons on K&N Air Filter

Post by wyowillys46 » Wed Jan 24, 2018 11:39 pm

And some more reference material.

https://www.donaldson.com/content/dam/d ... -Guide.pdf

Pg. 253
Two of the most common air cleaner
servicing problems are:

1. Over-servicing: the least efficient time in the life of
the filter is when it is new. Filter elements increase
in efficiency as dust builds up on the media.
However, standard filters already have a higher baseline for filtration efficiency than gauze type (K&N etc) when new. While both increase in efficiency (per Donaldson literature and K&N statements) as they load up, a "paper"element will continue to outperform. The Donaldson guide is good reading. And air filtration is one of, if not the largest key to engine longevity.
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Re: Pros and Cons on K&N Air Filter

Post by 4REICH » Wed Jan 24, 2018 11:47 pm

The filter on my 650 looks like some type of hair, is this stock? Does it hold up and can it be serviced? It seems to be clean but really stiff unsure what to replace it with. I have a set of k and n pods on my 750 they seem to work well, any drawbacks to using these?
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Re: Pros and Cons on K&N Air Filter

Post by Snakeoil » Thu Jan 25, 2018 11:09 am

I think I've mentioned this here before, but since this seems to be a new discussion with new folks...

I read an article years ago written by a guy that worked in a stone quarry. I'm talking big time, serious stone cutting/moving business. It's was a perfect test bed to accelerate the effects of inlet filtration changes. K&N came to the mgmt. and told them they could save them a fortune on filtration costs for their off-highway vehicles by switching to K&N which can be cleaned and reused. If I remember correctly, the cost to install new air filters in a big bulldozer or Euclid truck was something like $5000.00. Multiply that by the number of vehicles and the costs add up quickly. So the owners were very interested in what K&N had to offer. So, they bought filter set-ups for several of their vehicles as a test bed to measure performance (as in filtration, not HP) and track it against similar vehicles running OEM filtration in the quarry. The guy that wrote the article also switched over his pick-up truck to K&N at the same time. Keep in mind, that the air in an active quarry is pretty much always laden with stone dust. Even on a calm day, a truck running across the quarry creates its own dust storm.

After whatever was the standard filtration period, the owners dumped the oil on the vehicles, bot with K&N and with OEM filtration and the K&N vehicles all demonstrated significant increase in particular contamination of the engine oil. Enough so that the owners abandoned the K&N products and put OEM paper filters back into the test vehicles. The guy that wrote the article, however, did not believe the results and kept the K&N filter in his truck. I'm sorry, but I don't remember just how long he ran it. But he did clean it on some schedule and otherwise, did all the proper maintenance on his truck. Within some period, a year or perhaps more, the vehicle seemed to be down on power and I believe it started to smoke a bit. So, they pulled the engine and tore it down. They found that the cylinders were all conical to a significant amount. It had to be rebored and OS pistons installed. Needless to say, he went back to OEM paper filters.

Some will argue that the quarry atmosphere is an extreme and not representative of normal street driving. And I think that anyone would agree with that. But what it did prove what that the K&N products do not filter as well as paper elements and the user can expect more wear when using K&N from particulate contamination that he would see using an OEM type paper element.

One last point, if anyone here is a NASCAR fan, tell the folks what you see under the hood of those cars? Do you see "high performance" K&N filters? Nope. You see huge paper filter elements. They are huge to provide the flow area those engines need without compromising filtration efficiency.

So, is your Ural going to suffer a premature and horrible death because you run a K&N. Doubtful. Will you see a marked improvement in performance if you run a K&N? Equally doubtful. Yeah, you might be able to see it on a dyno run, but doubt you'll feel it in the seat of your pants. The point here is save your money. If you already have one, run it. Only clean it when the engine starts to foul plugs (that's an exaggeration for those to take everything literally here) and you'll be pretty sure you're getting max filtration efficiency.
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Rob
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Re: Pros and Cons on K&N Air Filter

Post by rivers » Thu Jan 25, 2018 12:28 pm

4REICH wrote:The filter on my 650 looks like some type of hair, is this stock? Does it hold up and can it be serviced? It seems to be clean but really stiff unsure what to replace it with. I have a set of k and n pods on my 750 they seem to work well, any drawbacks to using these?
The stuff was referred to as horsehair but don't know if it really was. It was fairly common way back when. I don't like the pod filters. Pretty much designed for max air intake at WOT/racing etc and hard to sync/balance the carbs for normal road use. Also they "really don't like rain". Boxer twins like both jugs pulling calmer air from a common plenum. If they're working for you, keep'em. I'm big on if it's running good doan mess with it.
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Re: Pros and Cons on K&N Air Filter

Post by URAL CT » Thu Jan 25, 2018 1:06 pm

Yes sir...my thinking is similar to Joe's. I use a, MotoGuzzi (I think) one piece K&N filter on the ModTop modified air filter box on my rig. I'm happy with it, works great for my use. It's a Ural so other than my preference, I do not even think of performance...like an increase in power...etc...to each his own. :P When I feel like it I, I'll clean the filter, also I inspect the K&N at every oil change then I make that decision...unusual change in the normal MPG will make me inspect the filter too. I also have a clean spare to use for the swap. I do not go off roading any more & try to avoid dusty roads plus I keep my speed between 55/60 mph, been retired since 2009 & have never been in a hurry since. :mrgreen:
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Re: Pros and Cons on K&N Air Filter

Post by 4REICH » Thu Jan 25, 2018 10:16 pm

Thanks Rivers and URALCT for the input. I will stick with the pods for now and track down a paper filter to replace the bizarro fiberglass horse hair element that I can't figure out how to clean
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