Article on K&N Filters

[Kejtar]

K&N makes a foam filter cover for times when you are in very silty or dust areas, I ran one on mine, never had dust problems in the air tube and oil remained clean

Actually correction I stopped by and talked to the K&N folks at their booth last year at the 4wd Expo in Pomona and they said that the idea behind the foam is for mud/water protection (more mud then water) while they have a different prefilter (which I did buy so that I don't have to clean the filter as often from sand stuffs) which is kind of like a wrap and it can be purchased for your exact filter (if you have cone that is) from places like Kragen (they have to look them up in their K&N catalog though).

 

[BLUTO]

K & N style filters

I happen to have a little "down-time" at work last night, so I went and read the owners manual for a '04 Dodge Ram diesel (been thinking of one....down the road....maybe? ). Anyway, Cummins states that: If you run a K & N style "washable" filter and not the factory-style filter....they will void the (10yr/100Kmile) warranty. Due to the amount of dirt that gets by these filters and into the engine. They also state that you need to use a low ash content oil to prevent sludging and burnout of the valves.
There were other do's and don'ts, but you get the picture
BLUTO

 

[Kejtar]

Re: K & N style filters

I happen to have a little "down-time" at work last night, so I went and read the owners manual for a '04 Dodge Ram diesel (been thinking of one....down the road....maybe? ). Anyway, Cummins states that: If you run a K & N style "washable" filter and not the factory-style filter....they will void the (10yr/100Kmile) warranty. Due to the amount of dirt that gets by these filters and into the engine. They also state that you need to use a low ash content oil to prevent sludging and burnout of the valves.
There were other do's and don'ts, but you get the picture
BLUTO

This is BS.... it's like the fact taht you take your XJ wheeling and it breaks down and they try to claim that they can't fix it and so on..... although here they put it ahead of time. All this means to me is that what you need to do is have a stock filter, semi dirty(as in slightly used), handy so that you can put it in, and so it doesn't look like you just put it in

 

[XJguy]

Even if that extra sheild on the K&N filter worked, with all the material in the way of airflow, wont you just negate any higher air flow that K&N claims?

I tell you, I experienced the filth first hand, long before I even had internet service and read about the other people experiences, I experienced tons of silt coming in....it was not long after the K&N installation that my bearings swent caput...several of them. Took some time for me to put one and one together.

XJguy

 

[REDXJ4FUN]

I have use K&Ns in a couple o my jeeps and haven't had bad results yet but i do plan on going to a Amsoil filter. I used to race 4wheelers and at first i got a K&N and it sucked in those conditions and did cause problems. I switch to a twin air double filter and a good oil(i belive it was clean air or something like that)and real liked it. It stoped much more crap than the K&N and was much easier to clean.

 

[XJ Saga]

i haven't found an "independant" test that knocks k&n filters that was acutally independant. when you read through the fine print of the "test" it has always been sponsored by another air filter manufacturer (or masked as their parent company).

That is exactly what is going on, excellent point. There is more subterfuge going on under our noses then I'd care to admit and it's sad. I was anti-K&N for years until I used my analyst skills to do some extended research into the issue because I became very suspicious of all of the "negative" reporting about K&N no matter where I went. After several months of researching the issue I've come to the determination that well over 90% of the so called independent tests and articles were propaganda dished out by competitors. Now I have seen oil analysis reports which are much more neutral on the issue and all of them indicated to me that in oil analysis reports where a K&N was present for the entire time did NOT indicate higher levels of Si (silicate). There were maybe a couple with somewhat higher levels of Si however those particular vehicles tested had a high percentage of Si in the motor internals (bearings) so the results are somewhat skewed in that aspect. I recommend to anyone who is purely anti-K&N to do some more in-depth study to look beyond the smoke and mirrors of competitor propaganda. On the issue of big hp claims by K&N, there have been some marketing points done by K&N that I have questioned but never considered suspect, there are a few big hp gains to be had with a K&N set-up depending on your vehicle (chevy for example). As it pertains to our 4.0's, K&N has done a find job of giving us the right tool to give us more hp, now the issue is to finish where they left off and this pertains to any vehicle: turn your FIPK into a true cold air kit. The person that initially addressed this issue was Dino. I would invite anyone to do what Dino has done to his intake set-up and you will notice a hp gain, it's simple thermal dynamics and physics playing a large role here. With the K&N FIPK modified to a "cold-air setup" you can expect a 8-10hp gain if done correctly. The K&N debate will go on indefinitely, but the key is to do your own research to come up with your own determination.

 

[RyanSullivan]

i haven't found an "independant" test that knocks k&n filters that was acutally independant. when you read through the fine print of the "test" it has always been sponsored by another air filter manufacturer (or masked as their parent company).

the amsoil "tests" are a good example. if amsoil says that k&n filters are no good, more people will buy amsoil air filters instead.

i'm running a k&n cone on a rusty's air tube. the tube is painted gloss black so it's easy to check for fine particle dust and i have yet to find anything. i threw out the stupid plastic hose clamps and bought some of the "old fashioned" metal screw types to keep things secure and if i know that i'm going to be in really dusty conditions i put the dust sleeve over the filter and wash it out in the dishwasher when i get home.

works fine for me.

Do u have a throttle body spacer on your jeep? I was thinking about getting the rustys airtube but heard it won't fit with the spacer on?

 

[rockwerks]

tell you, I experienced the filth first hand, long before I even had internet service and read about the other people experiences, I experienced tons of silt coming in....it was not long after the K&N installation that my bearings swent caput...several of them. Took some time for me to put one and one together.

The only time I have seen a problem is when they are not properly maintained adn used as specified.....if you just stickit on a go yes you are gonna have a problem...

 

[XJguy]

I maintained that Jeep meticulously, 1500mile oil changes. I even cleaned the filter and recharged it before the recommended 10k miles. Maybe their control is not that good, maybe the gauze in those filters is inconsistent enough that we see these discrepencies; so your purchase is the luck of the draw....just guessing here, since some say they see no oil or sediment in the airpath.

XJguy

 

[TOZOVR]

I'd say I'm Independant. And I'd say that on an internally stock 4.0, you're wasting your time messing with the intake. 1.8 hp on a good day tells me that there's no bottleneck there.

The filter debate will wage on longer than we'll all be around. Wanta to get a K&N? Do it man, just please don't claim massive HP gains and better filtering.

 

[8Mud]

Paper filter, washable filter. My choice was primarily for practicality not HP.
The early XJ´s and the old oil in the airbox problem. I clean my crankcase ventilation lines often and still get caught on occasion with a quarter of the paper filter oil soaked. The oil soaked portion of the paper filter is mostly usless, doesn´t flow worth a darn. Throw away the paper filter and buy a new one.
Run through a decent puddle and your often bound, to splash a little muddy water into the filter box. Throw away the filter buy a new one.
Fall into a hole and suck some serious water, the paper filter looks like a wad of trash. Throw it away and buy a new one. With the K&N (or comparable) reuseable filter, you can wash it out in a clean water puddle and at least have something to get you home.
On dusty roads in the summer, I often run a 3-5 micron pre filter. Buy it by the square yard at a filter supplier. Can be washed and reused for a few times, blown out with air and reused many times.
A washable filter makes sense for me and will probably pay for itself in a couple of years.
My XJ does seem to rev a little faster, with the bored out throttle body, the K&N in a stock box and a 2 1/2 exhaust. Don´t know about HP, but my 4.0 seems a little zippier than most.

 

[rockwerks]

so your purchase is the luck of the draw....just guessing here, since some say they see no oil or sediment in the airpath.

Yeah my luck of the draw on ten straight vehicles

 

[JohnBuuu]

I'd say I'm Independant. And I'd say that on an internally stock 4.0, you're wasting your time messing with the intake. 1.8 hp on a good day tells me that there's no bottleneck there.
.

i think yer right about that....on the other hand, when i put the FIPKII on the ZJ5.9, there was a very clear difference in power id have to guess 7-10whp.
i suspect with both of these, that smoothing out the air inlet tube and so on, probably yields more power than the filter itself. thats neither here nor there though, and i have nothing to back that up.

also, to whomever mentioned that DC will void your warranty due to running a K&N....thats true. its also true for oil filters....your ony supposed to use fleetguard, cummins, mopar, and a few select other oil filters. I cant decide whether thats because the Cummins Diesels really need that, or whether its basically an attempt to force you to buy mopar stuff, and an excuse to further this (illegal) idea that you can just arbitrarily void peoples warranties, that seems to be so popular with the american auto industry.
now with oil filters, and companies like FRAM out there, i can see the mandate from DC that you use an approved oil filter(the specifically proved that frams filters dissintegrate a certain way and are responsible for many ruined engines), however i wonder about the validity of the KN claims they make.
the problem is you cant tell if the auto manufacturers have concrete evidence against the KN, or if as above, its just an attempt to force you to buy OEM.
i dunno, i dont think there is compelling evidence to discard K&N, however, there do appear to be risks with them.
i think im gonna see i can find something conical that filters much better.
end pointless ramble

 

[TOZOVR]

Paper filter, washable filter. My choice was primarily for practicality not HP.
The early XJ´s and the old oil in the airbox problem. I clean my crankcase ventilation lines often and still get caught on occasion with a quarter of the paper filter oil soaked. The oil soaked portion of the paper filter is mostly usless, doesn´t flow worth a darn. Throw away the paper filter and buy a new one.
Run through a decent puddle and your often bound, to splash a little muddy water into the filter box. Throw away the filter buy a new one.
Fall into a hole and suck some serious water, the paper filter looks like a wad of trash. Throw it away and buy a new one. With the K&N (or comparable) reuseable filter, you can wash it out in a clean water puddle and at least have something to get you home.

I pulled this out from halfway up his intake tube towards the TB...which was also full of H20

 

[Dr. Dyno]

I pulled this out from halfway up his intake tube towards the TB...which was also full of H20

So you can imagine that a paper element would have disintegrated and probably would have been sitting inside the TB. That K&N may have just saved the engine from a hydrolock.

 

[Gojeep]

Spoke to the engineer of Airflow Snorkels as he does flow tests all the time. He said he would never run any of the oil type filters at all. There is too much variance in the oil amount of oil added and the way it is distributed through the filter after servicing. To little and the partical size is too great and you get dust through but good flow. Too much and you get good filtration but poor air flow.
Just think about it, it all comes down to the surface area size and pore size. You cannot increase the pore size to improve flow without letting more particutates ( dust ) through but you can increase the surface area while still using an acceptable pore size by fitting a larger filter or having more and or larger folds in the same size!

 

[XJFREK]

Don't know if any of you get JP magazine, but I bought the Twinn Air foam air filter intake advertised in the back of the mag back in July. I figured it had more usable surface area to suck in air than a K&N cone filter and was only $100 for the kit plus 2 filters. I realize this adds nothing to the debate between K&N and stock filters, but awhile back someone asked about foam filters so here you go. I also run a 2.5 in exhaust with a 3 chamber flomaster muffler. Between this and the foam filter I have noticed gains in acceleration and power. Specifically, now when I put my foot in it, even while towing a 3000+ lb trailer, the A/C doesen't kick off like it used to. I ran a K&N in the stock air box before switching to this setup, and was told that the A/C issue was normal under load. I read once that a K&N cone filter like the one's offered in the FIPK kit had about the same surface area as a stock replacement filter, which makes sense, although the FIPK kit does away with the stock airbox. The foam is probably less restrictive than the K&N, but at what cost? I haven't noticed the interior of the intake tube to be noticably dirty, but haven't really looked either. With stats like those above being thrown around it seems like these sort of mods are very much buyer beware. I don't plan on changing back to the stock airbox because I like the gains I've achieved. But I realize now I may be achieving this at the expense of my engine life. Guess it comes down to what you're willing to risk for certain gains in performance.

 

[8Mud]

TOZOVR Been there done that. Hopefully the filter kept most of the water out of the cylinders. The paper filter doesn´t stop much water, when it crushes (even a little). If your lucky, the cloth filter will block most of the intake.
I´ve pulled the plugs and pumped water out of the cylinders, luckily the motor stopped, before the hydro lock broke something or much sand got in there, to mess with the valve action and/or scratch the cylinder walls.
Having the bottom fall out of a mud puddle and water washing over the windshield is a bummer.
Sprayed everything up with WD-40, washed and dried out the K&N with some air and exhaust gases. Got me home to change the oils and check the cylinders. No permanent damage.
Been thinking about a snorkel. Had a setup that, with a couple of stoppers, I could pull air from the drivers compartment on my YJ (when needed). Probably gonna go with the same setup on my XJ, if I can find enough firewall to mount an intake. Open or cone filter isn´t really an option, drive through to much water.
I don´t hang many aftermarket items on the outside of my XJ´s. The closer to stock appearance, the fewer traffic stops (at least around here). Don´t feel, hanging a sign on the outside of my XJ saying modified, is smart. Just asking for a closer look, by a bored and curious officer. I´ve held off on the snorkle, roof lights, monster tires and serious lift. Don´t get pulled over much. Though the joungster at the local spray and wash, called the Police, because I covered his wash bay with mud. Cops said, he paid his quarter and laughed .

 

[XJ Saga]

The only big problem I see with K&N is when used while desert racing/offroading. Smart racers will use a K&N with a pre-foam filter (K&N also sells btw). K&N's by themselves were never designed for off-road applications such as racing or heavy equipment use and K&N knows this that's why they sell pre-chargers. The only reason I've got a pre-charger on mine is running it through car washes, driving in the rain etc. thats my concern, not dirt, but I've got a street jeep.

 

[XJguy]

In the 89 XJ I used to have I made my own airtube, doing away with the restrictive accordian hose and I used the largest conical air filter I could find. The filter I used, I was told is for an Acura or Honda. It was about 10" or 12" long and large in diamter with a 3" outlet. Very well made (Purolater), seemed to be made of paper, metal mesh, and then what appeared to be very fine cotton, almost like toilet paper in texture on the outside. The huge size of this thing and the number of pleating would surely flow as high or outflow any K&N...more CFMs than my internally stock 4.0 could ever handle even when dirty. If you want high flow, and dont care for the airbox, then build your own box to sheild form engine heat, heat shield the the itnake tube (smooth) , do away with anything that will slow or impair the air flow, and stick on the biggest air filter you can fit under the hood. I you want to you could even stick on two airfilters on a y-pipe and you can have the best of all worlds and not the tradeoffs that a gauze filter may potentially posses....such a setup should last, as airlfow goes, for a substantial amount of time before losing accountable CFMs. IMHO.

XJguy