whats a better intake filter, K&N or UNI?

[tom416ex]

What air filter is better. A K&N or UNI. I have an 02 400ex with some goodies. It has the K&N in it right now, but i hear uni is better?? So whats the true answer?!?!?!?!?!?!?!
Thanks

[trx400EXtreme]

IMO one is no better or worse than the other. people say K&N's let to much crap in the engine, but ive head one for three years now and i am COMPLETELY happy with it. as long as you have an outerwear on it it will work just as good as a foam UNI filter. i will also add that i ride DUSTY conditions. it gets really dry here in the midwest, especially when summer roles around, and again, the K&N works amazing.

K&N with outerwear no doubt. I was going to take pictures of what the inside of my airbox looked like and what the outside of my outerwears looked like and what my filter looked like. Literraly small piles of sand in the bottom of the airbox, sand/mud caked on the outerwear, dust everywhere. Want to know what my filter looked like? about as clean as when i got it out of the package. I went through water and all open air box lid no problems and ntohing at all got past and into my engine. There was so much proof how good it was I just had a smile like wow thats 1 great filter combo. When i had a foam filetr sand and dust and such would clog it really easy and get dirty much quicker bogging me down and making me clean it every ride even with the airbox lid ON! with the K&N and outerwear you dont have to clean it nearly as often. And if you want even more captain insano protection get the outerwear airbox cover which cover where your lid is. People will argue saying K&N sucks it let dirt and dust into their motor. No its maintainance. And the outerwear is a big key too. You get better airflow and better protection with the K&N outerwear combo than the foam filter. I really wish i had pictures of all the crap in my airbox and on my outerwears and how NONE of it even passed through.

[TheNewn]

People can go on and on about this. It's been debated many times.

I'm using a K&N with an Outerwares, if that tells you anything.

[Honda4life05]

yupp..k&m with outerwears

[Iliketogofast]

I use a K&N with an outerwear on mine, and I don't have use an airbox. There's never anything in my intake tube.

The outerwear stops water and mud, the K&N does a great job of getting everything else.

[tom416ex]

well i guess K&N it is for me still, but im guessing i should get an outerwear huh? It doesnt have one right now, but i clean the filter all the time. You guys are talking about the outerwear that goes on the air box or the outerwear that goes over the filter itself?? I guess either doesnt matter huh?

[trx400EXtreme]

the outerwear that goes around the filter.... and if you like to be even more safe, the one on the air box can only help.:macho

K&n best flowing. The people that get dirt in their intake tube is cause their not oiling it right. I used K&n with a filter skin and no air box and never any dust got in.

[tom416ex]

sweet deal guys. i dont have to mess with the jetting then right?? seeing how the air box will be open

Originally posted by tom416ex
sweet deal guys. i dont have to mess with the jetting then right?? seeing how the air box will be open

Normaly just changing a filter dont mess with jetting much but it depends if the jetting if the jetting is already off a little. If your just now removing the lid you wil need to adjust. You want to make sure your main jet is the right size before removing the air box lid. Then you adjust the needle.

[Honda4life05]

if you have had the air-box lid on and are now planning to leave it off i would re-jet..If ur not planing on running with it off i would reccamend running with it off unless ur in really wed conditions as long as you have the outerwears.

[tom416ex]

k thanks guys, yeah its already jetted, i got a bunch of mods done to it, i wasnt sure if it would effect it at all. Ill try running with the lid off for a quick ride and see what it does...

[tom416ex]

how do i know what outerware cover to get for my intake, all filters for the 400ex the same. I went to rockymountainatv.com. put in my quad and **** and it gave me choices. Those are the right choices correct??

[wilkin250r]

I saw a comparison study a while back, but unfortunately I haven't been able to find it again.

Ever since that study, I've been a firm believer in UNI filters, and I'll recommend them to anybody over a K&N (even though I use a K&N myself).

The initial results of the study were the same as everybody would expect. The K&N flowed better, but the UNI provided just a bit more filtration. Whoopee, we all knew that. It didn't take an engineering degree and $40,000 worth of test equipment to tell us this, duh.

However, the study also went into extended performance, overall dust loading, and total filtration capability over time.

I was suprised to find how quickly the K&N clogged up. I'm not exactly sure how the test criteria corresponded with "real life", but the K&N clogged up in about half the time to took for the UNI to get clogged. Not only that, but very quickly in the test, the K&N was SO clogged up that it actually had worse airflow.



I'm going to see if I can find that study again...

[TheNewn]

I'd very much like to see that study as well. But to add to it a little, everyone here has recommended K&N AND an outer wares to go together.

If i had the choice between Uni and K&N without an outer wares, i'd pick the Uni. But i don't have to make that choice, outer wares are cheap and effective.

I'd like to see how much time it was specifically in the test.

[wilkin250r]

Ok, I found the study.

http://home.stny.rr.com/jbplock/ISO5011/SPICER.htm

Let me decipher these results for you, because they can be a little difficult to understand.

The best filter in the study was a paper disposable filter, which isn't available for ATVs and motorcycles, so don't bother with that. Just concentrate on the UNI and K&N (the K&N was tested without outerwear).

The 4th graph down is "Initial Restriction". The units are inches of water, but it's basically a measurement of pressure difference. The lower the number, the more air passes through. You can easily see the K&N flows best. But like I said earlier, we all knew this.

The second graph down shows "Accumulative Capacity" This is the life of the filter, how much dirt it will hold before it becomes completely clogged. The UNI filter trapped and held 374 grams of dirt, while the K&N became clogged after only 211. And the dirt is fed at a constant rate, so the UNI lasted twice as long before it became clogged. The only part I don't know is how their definition of "clogged" corresponds to real life. The definition they use is a restriction of flow (10 in. H20) which is a very valid measurement, but I don't know what that does in real life. Is that a standard that somebody would see after 1 year of use? Is that the point you see a measured power loss on the engine? Is that the normal average lifespan of the filter? I DON'T KNOW


The most interesting graph is the 6th graph, the dust loading, as it shows the lifecycle. Again, we're only focused on the UNI and K&N. It is interesting to note that the K&N starts with better flow, but after 150 grams of dirt is trapped in the filter, it actually flows WORSE than the UNI.




I really would like to find out how their test criteria corresponds to real life. I'll personally give $20 (Paypal) to anybody that can put me in touch with Arlen Spicer, the author of the article.

[01ex400]

Firm UNI here. Have had both and would much rather buy a Uni, than buy a K&N WITH outerwears and have more maintence. Why buy both when a Uni does just as good job with less hassle. Just my opinion of coarse

[250r4life]

Originally posted by 01ex400
with less hassle.

less hassle? i would like to know how UNIs are less hassle then K&Ns

[01ex400]

What I mean was how it was stated that K&N gets clogged faster. But that does all depend on what kind of conditions you ride in. Don't be so quick to judge... I am running a k&n as we speak

I clean my k&n filter alot so I dont think a uni would out due mine. But the worst thing for K&n filters is clay dust which is at a lot of motocross tracks and it clogs the k&n up fast.

[ohsobad_chevy]

That is awesome data, very interesting. I have always used UNI filters and will keep doing so, simply because I know that they stop everything. Dust, sand, whatever.

My only complaint with UNI is that when oiled, the sand sticks very heavily to them. Has anyone tried a filter skin on a UNI, I think I will try that. Just don't know if they would constrict flow any worse?

[TheNewn]

you get all the oil from the foam filter onto the outer wares and it turns all sticky and is a b*** to clean...from my experience with my dads raptor and the outerwares.

[tom416ex]

well i think after all this. i am going to still stick with the K&N filter, no point in buying another filter when i already have one. All ill do is buy an outerware to put on it, and run the open air box.. That will be good for me. Thanks for all the opinions guys, it helped.....
but i dont think anyone answered my question. 400ex's only have one kind of k&N filter you can get right? so all i gotta do is find the outerware for my filter for my quad and get it right? I dont need the part number and junk corect...

[250r4life]

Originally posted by 01ex400
What I mean was how it was stated that K&N gets clogged faster. But that does all depend on what kind of conditions you ride in. Don't be so quick to judge... I am running a k&n as we speak

wilkin admitted he didnt know the exact perameters in which the filters were tested... without knowing that, it could be that it takes a week of riding to clog up a K&N, but it takes 2 weeks to clog up a UNI. if so, its pretty much worthless info...

as far as hassle, i think the UNI is much more of a hassle than the K&N. K&N's are much less hassle to clean and oil.

that being said, i have both K&Ns and UNIs for all of my bikes.

[wilkin250r]

Originally posted by 250r4life
wilkin admitted he didnt know the exact perameters in which the filters were tested... without knowing that, it could be that it takes a week of riding to clog up a K&N, but it takes 2 weeks to clog up a UNI. if so, its pretty much worthless info...

Indeed, that's would be really handy information. The test criteria they use, would that be after 2 days of riding, or 2 months of riding?

I'd really like to know. Maybe I'll look up Testand and see if I can get that answer.