BlikitSchmikit

Out of the 12 vehicles I've owned (not counting the 7 motorcycles) I've had either a K&N or "K&N Style/Type" air filter on all of them. I've had CAI's on my last two vehicles and noticed a "seat of the pants" improvement, but this is not empirical data; the companies selling their wares all have claims as to why theirs is the best ~ it's up to you to decide which best suits your needs. (motorcycles get K&N's too)

For stock filter replacement I'd go with a K&N. They're simple and aside from the occasional cleaning, you'll never have to do anything else with it ever.

current stable:
My wife's 91 Cherokee got a K&N drop-in replacement filter
My 07 JK: Banks CAI, PowerAid TBS and Cat-back exhaust "Monster system"
2013 Victory Boardwalk: Stage-1 performance exhaust, EFI- re-map, K&N

Back to what's applicable: I have been very happy with my Banks system. Installation was straightforward and easy. The only hard part was removal of the stock exhaust (difficult to remove one of the bolts (needed smaller hands) and one of the hangars). Again, not empirical, but "seat of the pants" it felt like a huge difference in performance! Yes, it's a tad louder and there is the "whistle" from the TBS, but that happens when the stock air-box and all the sound baffling is removed. Hard to notice with the top off and/or if you've got gnarly tires (currently sporting AT's so yes, I suppose I can hear it if I listen for it). The 3.8 will never sound like a V8, but the Banks system has a somewhat throatier sound, and it's better than stock - far better than the soup-can junk on a lot of "tuner" cars IMO.

MPG's is/was better than stock but I don't recall the numbers and I replaced more than just the air filter, so that had a cumulative affect. I get 18+MPG (going off memory, I want to say I get17-18 city/21-22 highway). I currently don't run a lift, have AT's and drive like grandma for the most part.

You stated that the K&N is about $70.00 - compare that to how much a paper filter costs and how often you replace those over a span of time. I think you'll find the K&N is far cheaper in the long run.

Chefbrujo

I use a drop-in K&N filter. It will give u approx .5 mpg increase on avg. Worth it in my opinion.

RedRockJeeper

Ditto with the k & N drop in. it saves you money in the long run. For CAI it would be the Banks with the exhaust.

Mark Doiron

If you go off road, get an OEM-style air filter. And carry a spare for when it clogs up.

"That said, both the cotton gauze type (K&N) and foam filters (Amsoil & Jackson Racing) showed the same levels of filtration. Both performed poorly compared to the fiberous or paper filters (Napa, Baldwin, and Mazda)."

Source: bobistheoilguy.com/airfilter/airtest1.htm

I recommend Wix (which is who makes the Napa products) for off-road use. If your Jeep is for the streets, then K&N (or Amsoil) offer very slightly improved breathing.

Mlupacchino

It looks as though, the intake packages are what gives the most notable increase to MPG. However, I have read a lot of people mentioning aftermarket exhaust in conjunction with the intake package to get the full MPG gain.

Is an aftermarket exhaust needed for better MPG with the intake? Or is it only a slight difference.

B 1000

Okay here I am again, so I kinda feel like a douche bag for commenting on every page.

BUT! What Mark Dorian pointed out is good info. Always good to see what people have done with an actual study vs. what's advertised.

On top of that, make sure that the info you're getting is from people running the same engine. I had an intake / exhaust system on my 3.8 and it felt like a bit of difference in power and MPG. Not a ton, but some. Later I put an intake / exhaust system on my Pentastar and it felt like I was towing something everywhere I went. Back pressure is pretty important, and a free flowing exhaust is probably going to rid you of much needed back pressure. Hence why people claim that taking the "exhaust loop" out of the 2012+ JKs actually hurts the performance.

Mlupacchino

Don't feel like a douche, I appreciate your input throughout the thread. That's what I want, to read experiences from people who have been there, done that.

I guess a replacement stock filter is a better idea. I'm just trying to decide between the K&N and an oiless filter like the Rugged Ridge. My local mechanic has nothing good to say about the K&N, said that people screw up the reoiling after cleaning, etc.

I've read a lot of mixed things from people. The reviews of the filter are great, with people claiming up to 2 MPG gains for simple stock replacement filters like the K&M or Rugged Ridge! However, the "real world tests" claim they don't do much of anything.

So at this point, it's just if I feel like rolling the dice, and which one I want to take a chance on.

Any further first hand experience would be appreciated, though!

GetLost

Would have to disagree with the paper air filter for "offroad" vs the K&N. The reason is that the k&n actually works better when the dust & dirt start to accumilate on the outter surface area, allowing for the best performance of the cotton/gauze medium to filter out micron particles. Having run k&n open on a dirt motorcycle, after hard riding in sand, dust,dirt. I would take a brush to the filter to clean off the outside of it. Couldnt get enough dirt to clog it ever! I put a drop in on a F-150 pick up, 1st time I cleaned was @ 55,000 mi. could've gone longer before cleaning. Had the truck 20yrs. W/that K&N. The only thing some folks do is over oil the cotton once they've cleaned it. But if they read the directions it should'nt be an issue. For what its worth... ;-) BTW put a K&N in my 2012 JK. Until I did a Banks stinger system install..(C.A.I.& exhaust)

all4wheels

I have always used K&N and still have one in my motorcycle but with my12 JKU I went with an AFE. pretty good filter and cool air intake but I will tell you if you are looking for gas mileage forget it no filter will do that and if it does it will be so minimal you wont notice. Remember a jeep is a box.

Chefbrujo

2010 jkusahara 3.8, 3.73's and auto Heavy XRC bumpers and rails and cable winch. Also i drive like an old man. Iv got a drop in K&N filter, a magnaflow exhaust and superchips flashpaq set on gas saver. It's been a year now and i can say that all together it's gained me on avg about 2mpg. On a long trip on the highway i'll get up to 5mpg better than avg. E.g. On a trip from norcal to az and back i was up to 22mpg halfway thru each trip! Amazing i thought. Long term the combo is well worth it.