You do not have facts, you haven't dyno'd tested them. Would you believe someone that said their throttle body spacer makes a noticeable difference? I sure wouldn't.
Sure. Do K&Ns filter well enough to get the job done? Probably. Is it worth it for maybe 5hp only at WOT? That's up to you. I've seen oily dirt in intake tubes and on turbo compressor wheels, needless to say, I don't like that.

http://www.dieselbombers.com/chevrol...r-testing.html

 

where do you get these air filters? are there any major auto parts stores that carry them and are they only the cone shaped filters? im not wanting to spend the money on a cai when the stock setup is just as good

 

Hahns since you seem to be so firm on that I don't know what I'm talking about.
Let me to show you my facts. These are pages pulled out of the 2012 Harley Davidson Screamin Eagle Catalog. Each have a Dyno showing how a K&N Filter improved the performance of the bike it was put onto.
Heres the link to download the digital version of this catalog
http://www.harley-davidson.com/wcm/C...p?locale=en_CA

Screamin Eagle Air filters are a Non Oil able filter made by K&N.
These dyno graphs shown on the pages I've pulled out of the Online version of the SE Performance catalog are completely stock Twin Cam/Evo Engines compared to the very same engines that are given a "Stage 1" or Screaming Eagle Air Cleaner kit.

Here is the "Twin Cam" Engine given a K&N Filter.
http://img3.imageshack.us/img3/5872/stage1dynos.jpg

Now an Older engine called "Evolution"
http://img196.imageshack.us/img196/5...stage1dyno.jpg

While these are not our truck engines the same effect will be had when using them however different it may be in the exact numbers. The 14" round filter will do better then the stock setup with the air hose since it has more area to suck air from. Provided you don't do alot of town driving since its sucking in warm air and not cold air. The cold air intake will do better since its getting direct windflow therefore getting more air into the intake. This in general is going to effect how well any filter performs since the more air its getting the more it is able to bring in.

Now for the dirt filtering aspect of the filters.
A dry filter made by any company will still let dirt and grime into the intake. This has been remedied by the Oil that K&N uses on most of their filters that are in direct contact with the elements and not protected by some sort of cover. The dirt and grime essentially sticks to the oil. If you don't oil your filter you lose that protection.

Now for my personal experience with the filters.
I ride a 2006 Sportster Custom carbed with a teardrop style K&N exposed Air Filter.
I have also rode on many occasions other sportster that have come in without a "Stage 1" air filter and many others that have the filter.
There is a very noticeable difference in throttle response and overall pull of the bike from a stop and on the highway.

By no means am I saying K&N is the best filter out there.
It is however my personal choice in filters and what I tell my customers, many of which who are friends of mine to go for when they ask me as a Parts Associate for a better A/C Set up.

I'm done with this thread.
No point posting if people don't respect my opinion.

 

The bike stuff is irrelevant and manufactures claims should always be taken with a grain of salt. I can find plenty of independent dyno tests that show drop-in K&Ns made zero difference, if you'd like.

The intake hose on these trucks is a good 4", way bigger than it needs to be. The throttle body on the other hand is only twin 48mm, the intake hose has over twice the cross sectional area compared to the throttle body. Where's the restriction again?

You obviously did not read the filtration test I posted (the test was conducted by ISO, by the way). K&N filters DO pass more dirt than other filters, this a fact. Just because it has oil doesn't mean it somehow magically traps all dirt. The K&N has HUGE pores, just look at it, that's why it flows so well, I'm not disputing that K&N filters flow well, simply saying it's not going to make a significant difference for our trucks as the stock system is more than adequate. K&N themselves do not say their filters filter better than others, they only claim at least 97% filtration efficiency down to 10-20 microns, while most filters are 99% (My AEM Dryflow is rated at 99.4%, down to 1 micron). I'm not saying not to run a 14" open filter, because I did for a long time, just don't do it because think you're going to gain noticeable power, do it for sound and to clean up the engine bay. Remember any of these potential small gains will only be felt at WOT, normal driving it won't make any difference.

 

Whatever Hahns.
I posted legitimate information if you want to ignore it be my guest.

 

i've not read all the posts but ill chime in and i have to say i agree with hans.
myne had a k&n open filter on it when i got it. hadne't been on there long. i took it off and put stock on it because of 12 mpg sounding a pissed off hoover and high intake air temps. from the factory the setup (unless your heat riser is open if you have one) is a cold air intake. just look at it. second the filter thats in it is plenty big. i've never had a prob with it. third i cleaned my throttle body when i got the truck. cleaned it again 3 months later. then got ahold of the factory inlet and filter housing. haven't cleaned it since. it lets in more air sure. along with the dirt and grime. but the filters on most cars are hugely oversized so that engine performance doesn't degrade as the filter fills up. so that said if you can't suck in more air (bigger motor) then how in the **** does it help? so should i bypass my oil filter so that more oil can get through the system? better yet the air filter to! i had one on my ranger and i never gained anything from it on it either.
with k&n
12 mpg 190 degrees farenheit air intake temps
with stock
16.5 pmg 130 degrees farenheit air intake temps.

by the way the higher temps caused alott of spark knock wich is gone now that i have the stock filter on it. if you want one go for it.
but on two different vehicles i've had em on they caused missery and cost more money in the end.

one last point back to the amount of air you use. when you press that button on the k&n display and watch the ball float around think about what would happen if that fan was smaller.

 

so its somewhat of a double edged sword? more air flow with the posabilities of little gain in performance but in the long rum will be causing more money and time put into the engine. thats what ive gotten from most of these post

 

im running a k&n and i like it