K&N Air Filters

[Bean Counter]

I've heard some anecdotal stories about how the K&N either bleeds too much oil into the engine or just doesn't protect like a disposable paper filter. Compared to the time savings of having to wash, let dry, oil, let dry, I'm good with the cost of just tossing the old one.

[Johnb317]

Depends on if your on highway or dusty back roads.  If back roads you'd probably be wanting to clean it more often.  I have one in my commuter.    The oil issue is that if you over oil it may coat the mas (mass air sensor) which depending on the truck can be easily pulled and sprayed with mas cleaner. 

[buglebuster]

If you are putting it on a diesel, thumbs down. They allow to much dirt through for a diesel engine.

[FC]

They certainly flow better but you don't want one on an intake where you have a MAF sensor after the filter as the oil will get on the sensing wire and damage the sensor. Toyota even has a tsb out on this.

I have a dry AFE filter in my tacoma and it's been great, get home from a dusty trip and just whip it out of the airbox and bang it out against the tire while gassing up. The afe filters are washable too but I haven't needed to yet.

[Antlershed]

Five thumbs down. They let way too much dirt through

[Special T]

Paper filters are where its at. There is a reason why over the road trucks (semi tucks) use them. I have used both KN filters and Paper on my dodges that drive mostly Highway miles. Paper filters aren't that expensive, and its not that easy to clean a KN air filter. Not to mention that once gummed up a KN isn't as good as a paper. The newer Dodges 03-05+ have a small gauge that measures the amount of flow in the filter. Mainly by figuring out air pressure. After cleaning a KN i was unable to get the same kind of readings  that i could get with a new paper filter. Do they kick ass for drag or street rods? YES! for real work conditions? Not even close. 

[Heredoggydoggy]

I've used the paper filters for years.  I'm sure K&N filters are good, but here in the dry dusty eastern WA climate, I just can't bring myself to trust them.  For a Street Rod or Sports Car that never leaves the paved roads, they might be OK, but for a rig that travels the back roads, no way!

[Bshiftbc]

Wow. This kinda blows me away! I recently bought an 06 Dodge (Cummins) truck and it seems everyone goes for the performance chip and KN set up as soon as they have the money. Glad I read this!

[Rick]

Wow. This kinda blows me away! I recently bought an 06 Dodge (Cummins) truck and it seems everyone goes for the performance chip and KN set up as soon as they have the money. Glad I read this!

The factory intake and filter on a Cummins is good for about 500HP. If you're making less than that,you're wasting money by buying an aftermarket intake or filter.

[C-Money]

I had them in my rigs, and I tossed them. Never noticed a difference. I went back to Wix air filters.

[cwbygotabigtrck]

 Ive ran them on a few gas trucks in that area there an ok filter. But I's never run one on a diesel the only guys that I know that have lost a trubo was with a K & N run and AFE or Airaid there great filter's

[Alchase]

So no difference in performance for the expense and effort to keep a K/N over the ease of paper. Seriously just change the paper more often.

I noticed they stopped saying "increases HP by 10%" in the advertisement, LOL

[KFhunter]

Wow. This kinda blows me away! I recently bought an 06 Dodge (Cummins) truck and it seems everyone goes for the performance chip and KN set up as soon as they have the money. Glad I read this!

The factory intake and filter on a Cummins is good for about 500HP. If you're making less than that,you're wasting money by buying an aftermarket intake or filter.

Is this for a 1995 12v too?  I got a few mods and it pulls the filter minder down pretty far even with a fresh filter.  Before the mods it wouldn't even budge even with dirty filter.

[MDGrand]

Here is the deal with K&N...

You DO get increased performance.. the danger is in the oiled filter.

According to my buddy who works at Ford of Bellevue as the Deisel mechanic..

The oil in the filter for a gas rig can over time coat the Mass Airflow sensor.. if you bring in a rig that suddenly has a "check engine" light come on.. and been running a K&N.. you may hear the dealer tell you to get rid of it and fork out a large chunk of change for a new sensor.

For a Diesel rig... the oil can get within the veines and turbine blades of the turbo. Not to mention, the oil getting within the induction system as well. This is bad over time and can cause a turbo to replaced sooner than inspected and run a little dirtier than needed and lose power over time.

Personally, I had a K&N on all my rigs before, but I decided to take them all off and go with stock. If you really want a different high flow air system, go with a dry system. Especially a diesel.. at the end of the day, the Tuner on a diesel is really where you find the biggest difference anyway. So, if performance is the big driver, than I would suggest to start there.

[Bshiftbc]

Very good info. Thanks a ton guys....
Think I will stick with the paper.
Is there one that is better than the rest?

[Mudman]

The oil in turbo not a big deal.  Ford diesel ccv coats everything already!  Dirt passing thru filter is a big deal.  I run big donaldson paper filter and it is great!  KN not that great, too much hype and pain in ass to clean properly.  15 dollar paper flows realll goood and last long time.

[BigGoonTuna]

had a K&N in my truck when i bought it, ended up chucking the thing.  a real pain in the butt to clean, and i could buy 3 or 4 paper filters for what 1 K&N costs, and the paper ones last a couple years each.

[Bean Counter]

Old thread now, but I wanted to provide some follow up. I have two vehicles with the same engine that live in the same environment. I run Mobil 1 Synthetic in both engines.  One engine uses a paper air filter and the other has a K&N. I've done several oil changes on both. I have to say that the oil that comes out of the engine with the K&N air filter is markedly cleaner than the paper filter... Just an FYI.. This is a very fair comparison given the two engines and that I don't have a dog in the fight (ie, stock ownership, etc).

I really should check the MAF on the one with the K&N though..

[Mudman]

Im not sure oil is a good indicator of air filter?  Turbo vanes and valves would be more affected.  Dirty oil might mean alot of blow by?

[Bean Counter]

   Just an observation. I'm a poser-jackwagon and by no means a pro. I do my own fluids, spark plugs, and what not and usually stick with the pros for alignments, timing belts, etc.

I usually buy gas from the same places and drive them in the same environment. In fact, the one with the K&N sees more off road time so I would think it should be dirtier. Its also older so I would think the rings would be more worn and let more exhaust into the oil.. Again, 

[Mudman]

You may be correct as im not a pro nothing.   I run Kn filters on toys but not my powerstroke.  My Stepdad is a cert mechanic 30+ years and isnt a kn fan at all.  Or pennzoil.

[tony04]

Im not sure oil is a good indicator of air filter?  Turbo vanes and valves would be more affected.  Dirty oil might mean alot of blow by?

[DoubleJ]

Five thumbs down. They let way too much dirt through

[Bean Counter]

So if the oil quality isn't an indication--how do we know how much dirt they let through?

[Mudman]

   Air flows thru valves to combustion chamber.  Dirt can damage valves and rings which can lead to blow by and same with valves so your oil observation holds water.  Bad valves and rings from dirty air cause poor compression poor running smoke from valve leak etc.  Check the air inlet behind air filter for dirt if you want to know for sure.

[Rick]

So if the oil quality isn't an indication--how do we know how much dirt they let through?

The only way to know for sure is to run a used oil analysis.

Everything else is just a guess.