They let too much dust particles by and there is no performance gain for the TJ. The paper filter is a lot more effective.

 

I would suggest actively avoiding them. They absolutely do not help. In some cases they may even cause problems.

 

I will happily trade you my K and N cold air intake for your stock intake

 

is it CARB legal?

 

X4 to the above, a K&N is the very LAST air filter you should install onto any vehicle that will be taken offroad... they let in way too much dirt. I had a K&N many years ago and was shocked when a friend removed the air intake tube to show me how much dirt and grime had made it past the K&N in and was inside the air intake tube and throttle body.

Not to mention its potential for more air flow only helps in vehicles that have restrictive air intake systems. The TJ's air intake was specifically designed to be non-restrictive, it easily flows more air than the engine can consume even at wide-open throttle and redline rpms.

 

Ok, I'll be the odd duck, I have the K&N replacement filter and have had it on my jeep for 100K miles. I have not noticed any more or any less deposits in the air intake tube or throttle body. When applying oil to the filter, care just needs to be taken to not apply too much oil. Like the rest have said, there is zero performance improvement. Just nice to wash it, oil it and keep on trucking.

 

Ok, I'll be the odd duck, I have the K&N replacement filter and have had it on my jeep for 100K miles. I have not noticed any more or any less deposits in the air intake tube or throttle body.

Come out and wheel with me here in my dusty SOCAL conditions and you'll easily see the dirt that got past it in a single day of wheeling. It's about as good at keeping grime/dust/dirt/silica particulates out of the engine as a screen door is at keeping dust out of the house in a Texas dust storm.

 

A K&N is only useful to the people that sell them and to people that get to prematurely rebuild engines. Stick with a Wix air filter.

 

I just took my K&N off and installed a stocker.

 

I would like to know if someone has installed them in their jeeps, if they work?

if they work at what? as a filter? as a money suck? as something else?

or i just fell for their marketing?

they are obviously good at taking your money. too bad they don't filter as well as a $10 paper filter.

i hope those $50 were well expended.

piss poor expenditure in my opinion....

 

I bought my Jeep at 57,000 miles. The PO had put in a K&N filter. The intake tube was dirty and the throttle body was black. I cleaned both around 60k and also put in a paper filter. I recently checked my TB at about 100K and it is nearly as clean as it was last time I looked at it 40k miles ago. I consider that good first hand evidence that K&N is a not a quality filter.

 

I have one and I regret the stupid noob decision I made with it. I should've snorkeled it properly instead of getting a cold air intake. It let's too much crap in to be useful

 

Wipe the inside of the tube and see how much grit got past the K&N. I ran one until I wiped the inside of the tube and felt how much garbage got through the filter. Put your stock back on and get a good paper filter.

 

I ran one years ago in my old 4runner, but honestly it was more work that I cared for. By the time you get all the hoopla to clean and oil it I'd assume just replace with the standard issue.

 

I see everyone is unanimously against the K&N. I am in agreement. I have a related issue, I think.

I live on Oahu, a very hot humid climate. I notice on cooler mornings my TJ runs awesome, but on those hot sticky humid days, something isn't right. I was wondering if there was a way to get cooler air into the engine.

So my question is: is there a way to get cooler air into the engine?

Thanks for your opinions.

 

...

So my question is: is there a way to get cooler air into the engine?

Thanks for your opinions.

Cowl induction will pull in air typically between 5-80° above ambient temp depending on RPM, how fast you are going and wind direction.

Are you sure intake temps are related to your engine problem? What isn't right?

How hot does it get in Hawaii? With a stock intake, the engine does just fine breathing hot air around 200°.

 

I would like to see K&N or other similar companies run a comparison test. 10k miles in the Northeast, southeast, Mid-South, Midwest, South and North west. Then release the results showing what for dust and particulates get through. Put this to bed once and for all.

I have the Banks cold air which uses a K&N made filter. No dust issues just better throttle response. Other than that, prolly wouldn't recommend it again. There isn't much noticable gain in fuel mileage.

 

not exactly the test based on regions, but dust is dust, if you wheel in it, it will hit your intake. also, its well known that the TJ OEM intake is non restrictive, it allows ~100 cfm more than what the I6 can consume at WOT, so there is no performance gain.

 

No K&N for my TJ. Suggest you use a paper filter.

 

That why I said about it. Real world use go have fun and test this stuff. ALL BRANDS, not just K & N.

 

To what end? The factory intake is more than capable of what we ask of it. There simply is no performance reason to change to anything else.

 

when an independent lab test 9 brands in controlled circumstances and it still isnt enough, nothing ever will be.

 

What that graph does not say is how it relates to real world driving conditions and what is the affect on the engine if the measured amount of dirt.

I have used kn on two street vehicles for over 100k on each. There is a drop in kn on the tj from the po and i have over 100k from me (150 on the odometer) my tj sees dust trails only a hand full of times a year and i have no concerns. Does it help performance on the tj, no. Would i use it if i drive in dust all the time, no.

One point a lot of people repeatedly state is the stock filter can pass sufficient air. Well yes. The engine is a positive displacement pump. It is going to pull in the volume of the cylinder. A less restrictive filter is not going to increase the volume of air. Any amount of restriction will make the engine work harder to bring in the air. That uses hp and is less hp it can output to the wheels. Again not saying in the case of the tj that the stock filter robs any measurable amount of hp.

 

My jeep came with a K&N CAI already installed when I purchased it. Is there a source for a paper air filter that is a clamp on style? I'm not having luck finding one. Maybe that is a bad idea with the possibility of moisture getting to it.

 

The CAI isn't doing anything for you, I'd sell it and reinstall the OE air intake. You won't notice any performance difference afterward. My used TJ came with a CAI but I replaced it with a used OE air intake.

 

I just did away with mine that came on my TJ. Best 45.00 ive spent.

 

The OE air intake doesn't just pass "sufficient air", it easily passes far more than the engine can possibly pull at WOT and redline RPMs. That is right from Jim Repp, Jeep's senior most engineer I had a personal conversation with several years ago. Their design goal, as Jim put it, was to insure it was completely non-restrictive and as free flowing as anything out there.

 

No fan of k&n, but know one has brought up the point that a clean k&n under performs a dirty one. A dirty oiled filter has more surface area to collect more dirt. The purpose of the oil is that the dirt that gets on the filter absorbs the oil, and gets sticky and collects more dirt. So most of there competitor's tests are not very accurate. Was talking to one of k&n's R&D guys years ago at a race and he was telling me how he has to lecture people on why the shouldn't over clean there filters, and how clean hurts there performance.

 

Kind of makes you appreciate the simplicity of a paper filter.

One of our company trucks has a KN that the big boss installed when it was his personal vehicle. It is simply a hassle to deal with and rarely gets serviced. I imagine it filters really good these days.

 

What if you don't take your jeep off roads though? Won't buying an air filter like a K&N at least save you money from having to keep replacing the paper filters? I mean even an air filter priced at 50-60 dollars, will pay for itself after you've had to replace the stock paper filter 5 or 6 times right? Then factor in the full time you'll have the truck...it seems like it's worth it, just because K&N's are cleanable and you don't have to keep buying new ones as periodically...Am I wrong in this?

 

I'd rather keep the crap out of my engine than try to save some small insignificant amount of $$ by not having to replace an ineffective air filter. Airborne dust, dirt, silicates, etc. is everywhere, not just in the desert. Just because you can't see the dust means nothing, it can be anywhere and everywhere. It's been over a year since I replaced my AC-Delco air filter, it does get blown out every so often creating a dust cloud in my garage... the very stuff that would have passed right through a K&N.

 

This thread alone should tell you what you don't want to hear. A simple search will bring up more, if your need it.

 

This thread amuses me. Love the interwebs!