K & N Air Filters Good Or Bad?

[barlowc]

Originally Posted By: Merkava_4
the engine oil stays cleaner longer while using the paper filter.

Stays cleaner in what way exactly? As verified by Silicon particle counts in a UOA, or just by visual observation of the darkness of the oil?

If I'm not mistaken, some oil turn darker faster and it's not an indication of how dirty it is. In your observation, was the same oil being used?

 

[Jim Allen]

Originally Posted By: barlowc
Originally Posted By: chubbs1
Ask Member "BarlowC", he has an Altima he uses a K&N air filter on and it has served him well.

As chubbs1 says, I have a K&N on my 2008 Altima. I bought the car new and dropped the filter in when I got it home from the dealer. My two UOAs (see here) don't show any signs of anything but fine air filtration. Silicon particle counts were at 12 and 13.

I also have a K&N in our 2007 Saturn which has a Honda V6 in it. Similarly, I dropped a K&N in it shortly after getting it home from the dealer. The one UOA I've had done on that vehicle (see here) had a Silicon particle count of 14, so again, indicative of fine air filtration. (I'll have a second UOA in about a month and am anxious to see the results.)

Prior to these two vehicles, I ran K&N filters in my a) 1998 Pontiac Grand Prix GTP which had a supercharged 3800, and b) 1999 Pontiac Grand Prix GT which had a naturally-aspirated 3800. While I never had UOAs done on those vehicles and therefore don't know what the Silicon levels were, I never had any problems with the K&N filters new out of the box, or after cleaning and re-oiling them.

With all that said, if I bought new vehicles today, I would probably just stick with good paper filters. But until I see any indication of the K&N not performing well in my current vehicles, I'll probably stick with them.


It often depends on where you live. People in a dusty rural environment would have the most potential problem and a city environment the least. An oiled cotton gauze filter (OCG, any brand) just doesn't have the efficiency of some of the more modern filter media but it may be good enough for many situations (an it's on par with the older industry standards).

My point is, why even bother to spend the money? Little or no performance gain???? Lower end of the filtration efficiency scale????

The only advantage is being able to clean it but I would argue the ultimate value of that point strenuously by pointing out that most replaceable filters are changed far more often than they need to be. If an owner changed his filter according to a restriction gauge and not some arbitrary mileage limit or via the "looks dirty" criteria, the gap would be narrowed to the point of immateriality.

Based on my research, I feel pretty confident in theorizing that people who can get by with an OCG filter in a good environment can probably run the factory air filter 80K miles anyway.

 

[abycat]

Well I have Changed my view on my K&N today. I bought my truck with a k&n drop in installed. I had some dust in the intake tubing so i took it all apart and cleaned it perfectly. That was about two months ago. Today I checked out my filter and Almost [censored] my pants. My filter had holes that let light through and maybe some small Sand particles could get through let alone dust. So I stuck my finger in one of the intake tubes and pulled out a dirt covered finger. I almost considered taking the bus to my parts store but realised i have been driving around with the bad filter already. I picked up a nice wix and im going to burn that pos K&N. So my vote is againgst (bad).

If anyone is going to run one make sure you have a way to test the efficiancy. I also run primarilly on the street and dont really see any dust.

 

[barlowc]

Why oh why didn't I take the blue pill? My reading of the thread would have ended and I would have woken up tomorrow believing my K&N filters are just fine. Instead I took the red pill, kept reading, dove into other threads on the topic, and now I'm wondering if the insides of my intakes are coated in fine black dust. Down the rabbit hole I go.

 

[bigmike]

Took mine apart after 40+k miles and found no dust. It really depends on climate.

 

[Garak]

Originally Posted By: bigmike
Took mine apart after 40+k miles and found no dust. It really depends on climate.


That, and application, too. I know there are some applications where I would use a K&N and others that I wouldn't. Some guys have problems with MAP sensors, so in such applications, one should exhibit caution. I have a K&N laying around for my old F-150. I may use it for that. It has no MAP sensor and sees use mostly in winter, and it's simply old.

It seems to me that the K&N style filter is, for a lot of applications, an answer to a question no one asked. Paper air filters are good for a lot of miles, usually, and are often too frequently replaced. A person doesn't need to change an air filter every 5,000 miles in the first place, so "extending" to K&N usage is a little weird in such a case.

I did have one in my Town Car years ago. I actually never washed and oiled it, since I ended up getting rid of the car before I actually needed to do so. I just inspected it. I don't think it caused any harm, but I can't see any benefit I got out of it, either.

 

[bigmike]

I mentioned on here not too long ago that I have a K&N cone filter and intake on my truck. I cleaned the MAF sensor and piping after roughly 40k miles of K&N usage. No noticeable dust or dirt was present. I even cleaned both the piping and sensor over paper towels just to see if it was dirty.

My climate and driving conditions must be perfect for it. I've not experience any problems with K&N filters since I started using them around 15+ years ago.

I don't recommend them for just anyone, however. Jim and others have provided evidence of the (non)necessity of a higher flowing filter. Widman has shown examples of poorly constructed K&N filters. Others here are like myself and have not had any issues.

There exists some proper demonstration and peer review here. But I'd like to request that we all avoid the demonizing of a brand or product on BITOG when it is not warranted.

 

[Jim Allen]

Originally Posted By: bigmike


There exists some proper demonstration and peer review here. But I'd like to request that we all avoid the demonizing of a brand or product on BITOG when it is not warranted.


I applaud the sentiment! Too much demonization happens here on all the separate forums. I fear it's tilting at windmills trying to stop it but I stand up and salute when someone does. Kudos to you sir!

Too many know only demonization as an argument rather than the presentation of fact... or even well-reasoned opinions or theories. IMO, there is nothing wrong with beating up on a product based on some sound (or at least semi-sound) arguments. The "it just sucks" argument doesn't cut the mustard.

That said, in light of the other more modern and advanced filters on the market, there is nothing wrong with comparing and contrasting the K&N with the other stuff on the market and there is a good factual basis to criticize the oiled cotton gauze filter in general. I take care to not pick on K&N in particular because they aren't the only ones using that design and they are a basically good company.

 

[Sunnyinhollister]

I can honestly say that I only used K&N air filter once and it was on a 1998 Jetta TDI - I actually saw a 2 mpg drop after installing it and a 2 mpg gain after removing it 6 months later. Considering it had what seemed like less than half the surface area it was no wonder.

I just can't see using one when there is no real benefit in performance or mpg, and there is a decrease in filtering efficiency. Add to that the higher upfront cost, warranty implications in case of a MAF failure, and it just is not worth it to me.

 

[barlowc]

Originally Posted By: barlowc
now I'm wondering if the insides of my intakes are coated in fine black dust

I popped open the airbox in our Saturn today and examined things. The clean-air side of the box was just like new and the intake had no dust of any kind. I'd say the K&N is doing a fine job in this vehicle. I'll have another UOA done in a couple of weeks which I expect to confirm low/average Si particle counts.

 

[TLY]

Originally Posted By: Chris142
Not on my Jeep! They offer a pre-filter for dusty conditions. That tells you right there how well they don't filter dust.

Take one off the shelf at the store and you can read the prices on the shelf through the holes in the filter.


What he said!... enough said.

 

[accent2012]

I bought one for my old ford taurus. It was great, the car would respond quicker than normal. However, when I cleaned the filter, I noticed how the cotton inside literally moved with little ease when running it under the tap.

I realized then and there that the efficiency dropped (assuming it was good in the first place) and I live in Florida, which means your air box will get filled with sand...

I ended up getting rid of the car for other reasons, but never bought one again for my other cars.

However, i still yearn for a permanent filter that I can wash/clean and not worry about having to go buy another.

I'm looking at AEM, but they don't have a drop-in filter yet for my 2012 Accent...

 

[Ken2]

The reports on K&N air filters are mixed. My experience with one in a Volvo is that the downstream (clean) side of the airbox had light dust where it never had any dust with an OEM-type air filter. There is no way it can influence gas mileage in any modern car with electronic engine controls.

K&N benefits:
--perhaps more air flow at high rpm & wide open throttle--same as OEM when the throttle is not wide open
--it can be cleaned and re-used

K&N drawbacks:
--cleaning and re-oiling can be a mess
--too much re-oil fouls the mass air flow sensor
--may pass more dirt through than a standard filter

I stick with OEM filters...MANN on the Volvo, Denso on the Tundra, and aftermarket HiFlo on the motorcycle.

 

[CharBaby]

I have a K&N air filter(and OE too) for all of my cars and one Fram Air Hog for another. I wouldn't use them in Phoenix for example(too dry/desert air, sand storms and pollution) but, where I live, they're OK/fine!

 

[heyu]

For a everyday street car ,More air flow (K&N filter) will tell a computer regulated engine MORE GAS flow ,,,I put a K&N on a 94 import and lost 4 miles to the gallon ,Needless to say it was a waste of money and the K&N is back in the box for the local flea market

It is common sense more air flow more = more gas flow = more horsepower /but only for racing vehicles only

 

[cutter]

Originally Posted By: MuzzleFlash40
I used to be a die-hard K&N fan, and used it in everything. Now I would only use it in a toy or hot rod that doesnt get driven often and would benefit from a few extra horses. I took them out of both of our daily drivers and went to purolator paper filters. The benefit is just not worth letting in extra dirt no matter how much extra it might be. JMHO


Same, I'm over it. One K&N will give me four OE style air filters, all of which would last pretty much the life of a car without making an oily mess.

 

[2James1]

Think the dry filters such as the AFE ProdryS would be a better choice. At probably about the same price. Clean with soap and water and no oil to deal with. That being said I have had UOA with Silicon readings between 13-30ppm using an AFE ProdryS drop-in. While that doesn't seem to be increasing wear I have since changed to carquest air filters (wix) but haven't sent an UOA in yet to see if the Silicon has dropped.

 

[ltslimjim]

^Curious to follow your app. If no filter changes Si values, it may very well be an issue you haven't found yet; a leak that is not intake tubing related can easily be overlooked.

 

[palmer_df0130]

I live in Yuma, AZ and drive around the very dusty canal and field roads and checked my K&N drop-in filter the other day. The top side of the filter and intake duct had no dust residue at all. The bottom side was a different story. No problems with my MAF sensor getting oily on my 99 Silverado.

 

[ltslimjim]

Anything like this?

http://www.knfilters.com/images/rdy-to-cleanL.jpg