K&N Air Filter Replacement Options

jrcotner

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New Ulm, MN
When I bought my '05 Rubicon it had a K&N filter system installed. I knew little about these, other than they needed regular cleaning. Not knowing when it was last cleaned, I got some K&N cleaner and oil and went to work. I cleaned and rinsed it and set it in the sun to dry. I was surprised to see light was able to penetrate the filter, unlike any other disposable filter I've ever seen. After searching the infowebs for some info on the K&N filters I discovered that in some tests they were pretty poor at filtering the air entering the engine. Not too surprising since I could see light through mine.

Is anyone aware of a replacement filter for the K&N intake that offers better air filtration than the K&N filter? I don't want to replace the entire air system with a stock unit, but will if necessary.
 
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You found why most people condem K&N piles of shat filters. K&N's statement "the dirtier it is the better it works" is so true as the dirt plugs up the holes in the gauze. That being a fact dont clean it "all the time" if you cant find and replacement. You mention system, like in one of the infamous "cold air intake systems" where you spent $300 to now suck in hot air from the engine compartment instead of the factorys true cold air intake from in front of the radiator? I digress....dont waste money on any Spectre products but AFE filters another option. You might want to look in your intake tract and clean it as well. Nothing like talc like grit getting sucked into the engine.
 
Is anyone aware of a replacement filter for the K&N intake that offers better air filtration than the K&N filter? I don't want to replace the entire air system with a stock unit, but will if necessary.

I'm not aware of anything as good as the stock system for filtration ability. My 05 LJ had an AEM "Brute Force" cold air intake system on it, and I think my very first mod was going back to stock. I got an OEM setup from Davey's Jeeps.
 
Is anyone aware of a replacement filter for the K&N intake that offers better air filtration than the K&N filter?
I don't have part numbers offhand but take the dimensions of your current oiled gauze filter and match them up to a synthetic media dry filter (non-oiled) from the likes of AFE, AEM, etc

https://afepower.com/build-your-own-filter
 
K&N filters do have a place, just not in my TJ. We used them in racing because they were much less restrictive, and the engines we built were very responsive to a less restrictive intake system. Less restrictive means less filtering, unless you provide significantly more filter surface area. Getting enough area to be less restrictive and filter efficiently is a big filter, and fitting it on a vehicle isn't really possible. Plus, as I understand it, the 4.0L I6 isn't really responsive to less filter restriction, although I have no data to back that up, as mine is unaltered, and I'll likely keep it that way for ultimate reliability.

In racing, the reduced filtration is not much of a concern because engines are typically rebuilt between events. I don't plan to rebuild my TJ's engine once a month, so I use the stock system. ;)
 
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I don't have part numbers offhand but take the dimensions of your current oiled gauze filter and match them up to a synthetic media dry filter (non-oiled) from the likes of AFE, AEM, etc

https://afepower.com/build-your-own-filter

My wifes Camaro has one of the non-oiled cone filters on a CAI system. It’s washable/reusable and has worked great so far. @jrcotner if you’re absolutely wanting to keep the aftermarket intake, I’d go the non-oiled filter route.
 
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with my tnt fenders and york OBA, i had no choice but to get an aftermarket intake so i went the k&n route. did some work on the jeep after about a year of having the k&n system on there and i had never seen so much dirt inside an intake tube in my life.

went the windstar box route after that and now i keep the k&n in a storage box for smog tests.
 
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Thanks for the input. It confirms what I thought, the K&N filters aren't too good for anyplace but the track. I'll be checking around for a used replacement OEM system. If I can't find one I'll certainly check the TJ site vendors for something.
 
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....You mention system, like in one of the infamous "cold air intake systems" where you spent $300 to now suck in hot air from the engine compartment instead of the factorys true cold air intake from in front of the radiator?

The stock box pulls air through the snorkel in the engine bay. Air flows through various locations into the engine bay (through and around the radiator, through the headlight buckets and to a lesser degree from underneath). How can any of these be considered 'the factorys true cold air intake from in front of the radiator'?

Were you being facetious or am I missing something?
 
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Nothing wrong with replacing the K&N with another cone filter of another brand.
A prefilter will help it last longer. I had an Outerwears on mine before I switched back to stock.
I had to add two pre-filters to my K&N to get it even close to filtering acceptably.

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The stock box pulls air through the snorkel in the engine bay. Air flows through various locations into the engine bay (through and around the radiator, through the headlight buckets and to a lesser degree from underneath). How can any of these be considered 'the factorys true cold air intake from in front of the radiator'?

Were you being facetious or am I missing something?

You are correct, got the TJ/YJ's factory systems mixed up. I was thinking about the YJ where the air box snorkle protrudes past the radiator support and does pull in outside ambient temp air.
 
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I’m new here and was just browsing when I came across this thread. I have used K&N filters for many years on a variety of vehicles. My opinion is quite different than most of what I read. Never have I experienced any of the issues mentioned here. K&N filters do not void factory warranties. Why? I’ve used them in dirt bikes in the desert, ATVs, 4 wheelers, Duramax diesels, Tahoes, suburban, Ram trucks, Toyota truck, Highlander, still using on a GMC Envoy with 240k (on the other in-line 6 out there) that has had a K&N almost its entire life, and a few more. Never, ever had an issue and in the big engines breathing is everything. I recently purchased a 2006 Wrangler 4.0 and it soon will have K&N. Now I’ll back up my thoughts. Take any standard dirty air filter Fram etc, and blow air through it and see what you get. K&N filters are oiled for a reason, oil collects and TRAPS dirt, dry filters mostly just collect. One post said they could see light through it, yes! That’s where the oil comes it. If K&N was as bad for your engine as many of you have stated, they would have gone under 20 years ago. They are reusable as well.
 
I have an AFE Pro dry filter with a filterwears pre-filter on it. My engine compartment needs detailed badly from all the dust and dirt everywhere. Pop my intake tube off of my throttle body and wipe your finger inside. Clean as a whistle…
 
This is one of the searches that got me reconsidering K&N filters. Though not a perfect lab-quality test, he is pretty thorough.