K&N Air Filters - Worth the Money?
 

Hi to the group!

I just wanted to see what the general consensus is on adding a K&N air filter to a auto vehicle to help improve gas mileage. Is it really worth the money?

I have a 2000 Honda Civic EX w/ auto trans and am trying to squeeze every mile I can out of each tank of gas. If it only helps .1 mpg, I am not sure it is worth it. If the change is sufficiently higher than that, I am all ears.

Let me know. Just wanted some wise advice from the group before I go down this road.

Scott

yes! its worth its weight in gold. all you need is the recharger kit for 10 bucks and your good to go for a long time....

https://www.fuelly.com/attachments/fo...a4d7dd0004.gif

been covered. done PROPERLY (right amount of oil) it's at most 1-2 mpg gain. get too little oil and there's almost no filtration ability. too much oil and nothing will happen except an oily intake pipe. If you have a MAF sensor, too much oil can mess it up... occasionally permanently.

Scott,
The short answer is a definite YES.
Proper lubrication as already stated is the key.
Too much oil and the oxy sensor won't talk to you any more either.

Cheers , Pete.

IMO, they should be well sorted for Civics, for other models, do your research, some applications don't flow as well as good paper filters. If there isn't a "performance" application for the filter, i.e. there is no performance model in the line-up that that filter fits, or no large following of modders for that model, then I'd be inclined to be skeptical about them. I have a theory that the Fram Airhog's should be better for these models, due to expecting that Fram know what their paper filters flow, and make the airhogs flow better. Whereas K&N doesn't seem to do as best they can for non-performance models unless nagged by enthusiast groups. However, Fram seem like they have given up on the airhog line, and they may be hard to find. I know Fram has a bad rap for oil filters, but I've always found their air filters decent. Well the normal ones, not so impressed with the new heavy duty one. Anyhoo, what led me to these opinions in part was that the K&N panel filter is regarded by Escort enthusiasts as being useless, whereas I have been rather impressed by the airhog I got for mine. K&Ns are also regarded as tame for mopar 3.0 V6 applications, so I was eager to get an airhog for Marvin, but have been having trouble finding them in stock anywhere.

So any model that K&N really has put performance development time into may be superior to airhogs, but models they have neglected may fare better with airhogs.

kamesama980　made a good point. If you value your MAF sensor (and in all honesty, you SHOULD value it A LOT), then you shouldn't mess with the K&N. Lots of guys over on the tdi club forums either a) didn't hear this advice or b) went against it. They sure paid in the end -- about $200 for a new sensor. Now, not all cars are prone to this kind of problem, but I personally would never let one of those things near my car.

www.bobistheoilguy.com has an excellent rundown of air filters. Basically (if I am remembering correctly), they found that the K&N provided both fairly bad air flow and terrible filtration. As in, tons of sediment will go RIGHT past it, and straight into your beloved engine. That, and filters really don't have all that much to do with FE. Change it on schedule and you will never see a difference.

I've had bad luck with them, even after oiling them with the high tack oil they still let alot of dirt thru, so I switched to foam filters, they alow simaler air flow, but stop more dirt, I give my foam filter credit for my car having 250,000 miles and perfect compresion.

I picked up a K&N air filter from autoanything for my 95 Civic EX for $35. For the price compared to a fram filter (which I heard was horrible and at one point used to be rated highly by Consumer Reports) it was about 3x more. It seems one of the selling points of the K&N is the fact that it'll last for your vehicle's lifetime. You would be making up the costs in 3 air filter changes. I've also heard about the damage from MAF sensors and that can also be contributed to a customer using excessive oil when "recharging" the filter. K&N's response: https://www.knfilters.com/MAF/massair.htm

As far as any gains in MPG, it's hard for me to tell at this point. I have too many variables in place that change my overall mileage and I unfortunately won't be able to perform any type of controlled testing in the future. If the scan gauge was compatible with my car I might be able to provide more info but so far I haven't had any issues. One of my friends uses it in his 1998 Civic EX with no issues. He's also not running stock parts (turbo engine, etc.).

I second everything Erdrick said above. Bad filtration especially (which means that IF you live in the midwest all that SALT is gonna get in your engine and into your oil, think about the ACIDS that will be created eating your engine from the inside out!)

I used a K&N filter in my Z28. I couldn't say there was much of a change in F.E. from it.

I had some oil analysis' done while I had the K&N filter in place. The silicon (dirt) infiltration was no greater than with stock paper filters. No difference on my car at all. Perhaps the issue was not with the K&N but with how it fits into particular intake structures. Mine came with a gasket to make the fit proper. Others might be better/worse than stock paper filters in the fit for a particular use.

The instructions describe in detail how much to oil the filter media. In this case it is bad to be one of the more-is-always-better crowd. Simply follow the instructions.

Too right, a MAF is a relatively inexpensive lesson for them, the results of drastically overfilling the crankcase or transmission would not have been so cheap.

I was with my Dad once when he was fixing something one of those guys had already done. It had about a million nails in a simple piece of trim work. It looked like a porkypine.

I did get away with cleaning my MAF with electronic parts cleaner. Couldn't say whether it did a lot of good, but it didn't hurt anything noticable. I sprayed the heck out of it from every angle I could get on it. Let it dry. Put it back into service. Runs great.

i dont know what helped more, i got a CAI (dyno tests proven that on s-10's anyways that its not much less gains than the $300 K&N brand than it is the $60 ebay variety with a K&N barrel/cone filter, so lots of people have bought the ebay cheapy)

ive had it over 2 years and no problems whatsoever. i did see a slight gain maybe 1-2 but its a major improvement over the stock zig zag setup so i atribute that to mostly the smooth lined walls of the intake part.

but i dont have a maf to worry about just a temp sensor and then goes straight to the TB

...i should put the old filter stuff back on and see if it really does do anything. also heard punching holes in the airbox before the filter helps so it has multiple entry points.

There will always be somebody who only JUST heard about K&N filters and hasn't discovered the historical conversation.

So it goes with everything...

it depends on the type of MAF: hot-wire, sonic oscillator or w/e it is (karmon sensor?) and i think there's others. and how long you leave it on there like that.

Ford Hot wire MAF element carriers jam nicely into the top of a gatorade bottle... put 1/2 inch of isopropyl alcohol in the bottom of it, jam the MAF on top and shake like hell....

Whether or not it gains mpg or hp is really a moot point because we all know the gains are minimal to the extreme.

The real savings comes from the ability to reuse the filter instead of having to spend money every time the filter gets dirty. It pays for itself after a couple years depending on how often you drive.

Yes it does let more air in, therefore more dirt/dust particles, the amount depending on your area though is probably very minimal.

In short...it's worth it.

lol they dont have to look dirty to be dirty...after all since they get clogged with microparticles(and "live"(bugs)particles i doubt you can see microparticles with the naked eye:p

Here is an air filter test that was done with various filters.

You decide whether you really want a K&N in your air box.

airfilter/airtest

Hmmm by the way, just came to a realisation, better filter flow and cold air intakes are really just a way to cheat the fuel ratios slightly and run either a little leaner, or use less throttle angle for the same push. At the high end, performance can be improved... but efficiency wise the engine is actually less thermodynamically efficient... but!... the loss in thermodynamic efficiency is offset by the slight overall leaner ratio, the greater expansion of the air in the cylinder and a slightly lighter foot giving equivalent performance. In other words, for fuel injected, ECU controlled cars, it's a dirty hack but it works. Carburated cars may lose mpg. Anything with not very well mapped intake air temperature compensation, or not too sensitive MAP or MAF sensors could go either way.

Try the AFE PRO DRY S, much better than K&N. You never have to oil it and the silicon from my last UOA was 3PPM.:thumbup:

I did a K&N on my Mustang and my truck. No dif from stock plain paper filters. Well it cost more. After a few cleanings I'd bet they don't perform as well. So I removed the K&N and filter box from the truck and replaced it with a paper filter that has 4 times the area. Now I can tell a difference.

So, the AREA of the filter is what makes the real difference as far as air flow.

The K&N's use an oil on the element. So it would catch more dust.

when i first got my truck at 55k miles i thought my 3.0L was a bit sluggish. I put a k&n stock replacement filter and it woke it up. mainly over 2500 rpm I could feel the difference in wot only. it now has 137k on the same filter (cleaned 2xs) and still running strong.
Also, my wifes xterra 4.0L has the air hog stock repalcement, I could not feel the differance but she could.

I have used K&N on my V8 cars & trucks for years. My trucks are driven on dirt roads a lot so the K&N have paid off many times because they could be cleanned and re-oiled instead of replacing the filter every month.

I just upgraded my cars to the EA air filters from Amsoil. Time will tell how they work out.

Amsoil Ea air and oil filters remove the smallest particles and allow the highest flow for a longer time than any other.

I plan on having this car for a while - so for me, the $35 air filter was worth it in replacement costs alone (standard filters are about $9 a pop).

I've got 2 other Saturns in the family, both with autos - they got an extra MPG out of it, and I'm getting about the same out of my stick. That's a long time to pay off in MPG gains alone, but in maintenance, it adds up fast.

It's no miracle thing, but every little bit helps.

On a 2007 Toyota Yaris, and after using the K&N for 15 tank fulls, I find no increase in MPG. Not even .00000001% !

The only benefit I see from this filter is savings in $$ over buying the paper throw-away type.

In addition, I still question if the K&N is filtering as well as a conventional filter. However I think there might be a lot of downsides to the K&N like the possability of F'ing up the intake, sensors, etc...

Although I fell for it myself, I think K&N filters are a gimmick and frankly I have a bit of buyer's remorse having bought one.

I don't buy these for the performance or mileage increase. I buy them because they are reusable and it's less that I end up throwing away. Over time they end up saving me money but it takes like 60k to break even(including the filter cleaning kit) if you change a normal filter every 15k like they say for you to do.

I missed this the first time around.
Look at the link. Very interesting stuff.
I wish we had the results of a test with what replaced the Amsoil Foam filter, the Ea.

https://www.amsoil.com/storefront/eaa.aspx
Scroll to the bottom for cost comparisons.

MetroMPG tested air filters for mileage. https://www.metrompg.com/posts/air-filter-part-2.htm

https://www.metrompg.com/posts/photos/ACFBF2A.gif

I do not agree with that price comparison one bit. The K&N drop in filter for my car was only $34 at the Zone and a cleaning kit is only $12. The cleaning kit is good for at least 4 cleanings(if it doesn't, you're over oiling). Assuming you live in a dirty climate where you actually do need 25k cleanings, you're still at only $46 for 5 years. That's $9.20(not 18.73)/yr compared to Amsoil's $9.53/yr filter.

And how does no filter end up testing worse than OEM style?

I wondered that too. Aerodynamic concern, maybe? Perhaps the filter straightens out the flow which gets turbulent sans filter....or just that not enough tests were done and there was one bad test on the one no filter try.

Also, .8 micron = 0.0008 millimeters.

The smallest grains of sand are around .02mm. By the time something is .00Xmm in size you are looking at very small dust particles. These are obviously airborne and aren't going to just fall into the cylinder and build up. They will readily burn and get expelled out the exhaust port. Efficiency at .8 microns shouldn't impress. Oil getting past the rings and carbon build up breaking loose in the combustion chamber has much larger particles in it. (Most automotive engine oil filters are only rated to 8-10 microns)

Additionally, I've never heard of an engine with a K&N, or any filter for that matter, fail from poor filtration quality. Over oiling mucking up sensors yes, but that can happen from any wet filter.

I did a T test at https://www.graphpad.com/quickcalcs/ttest1.cfm

The result was no significant difference between OEM and K&N at the 95% confidence interval. But then again- the sample sizes are tiny.

Results below:

Paired t test results
P value and statistical significance:
The two-tailed P value equals 0.0577
By conventional criteria, this difference is considered to be not quite statistically significant.

Confidence interval:
The mean of KN minus OEM equals -0.5500
95% confidence interval of this difference: From -1.1853 to 0.0853

Intermediate values used in calculations:
t = 11.0000
df = 1
standard error of difference = 0.050

Learn more:

GraphPad's web site includes portions of the manual for GraphPad Prism that can help you learn statistics. First, review the meaning of P values and confidence intervals. Next check whether you chose an appropriate test. Then learn how to interpret results from an unpaired or paired t test. These links include GraphPad's popular analysis checklists.

Review your data:
Group KN OEM
Mean 70.6750 71.1750
SD 0.2784 0.0354
SEM 0.1392 0.0250
N 4 2

I think there's a reason Detroit abandoned the use of oiled filters over 50 years ago. People weren't maintaining them properly. The paper throwaway filters are much better - there's no oil residue to muck up the environment.

You can't argue with that ping pong ball display unit K&N has though. lol

Well, if I ever have the need to put ping pong balls in my air intake I will make sure to put a K&N filter on the vehicle first... ;)

LOL........why not......don't you want a car with balls??......LOL

^^^ ok....sorry I got a little OT.

After reading all that stuff, I don't feel good about useing any of the aftermarket air filters, K&N included so I don't think they are worth the money.......I am just useing the standard paper OEM type ones.

The paper ones last so long now. I replaced the paper one on my truck this summer, not because of mileage (~45,000 miles) or because the indicator was showing it was worn out (the air pressure indicator was still showing it was good), but because it was 4 years old and it was only $15 to replace.

-Jay