6 year old study of air filters, including the venerable K&N!

[JulesMaximus]

I have OEM filters in all my vehicles and I replace them according to the manufacturer's recommendations.

A lot of guys put the K&N in their bikes but it doesn't give any improvement in mine over the stock filter...just a complete waste of money.

 

[alphatarget1]

I just put in a WIX air filter in my subie. Maybe I should've gotten ACDelco instead. Longevity is my primary concern.

 

[CRXican]

No problems with my K&N filter.

I have been on car forums for years and have yet to see one post about engine damage or even MAF sensor damage from "dirt and or debris"

 

[PricklyPete]

I just put in a WIX air filter in my subie. Maybe I should've gotten ACDelco instead. Longevity is my primary concern.

Looking at the report...the WIX looks like the best compromise between the two. I doubt the longevity would really be hurt by the different between WIX and ACDelco...and that is assuming the products haven't changed in 6 years...and the accuracy of the test. I'm sure you're fine.

 

[PricklyPete]

No problems with my K&N filter.

I have been on car forums for years and have yet to see one post about engine damage or even MAF sensor damage from "dirt and or debris"

Did you mean "damage" or malfunction? Actually finding damage and directly relating it to the K&N would be difficult...but this thread alone already has one post where the engine was not working properly due to the K&N filter tainting the MAF. Why bother?

 

[CRXican]

Because it was probably user error. Like I said, I've had no issues with mine and the same can be said for my old "ricer" that had a K&N cone filter.

 

[Vette73]

Because it was probably user error. Like I said, I've had no issues with mine and the same can be said for my old "ricer" that had a K&N cone filter.

How is it user error. The old owner of my car got filter, put in car, and drove. It had less then 20k on it when I took it out and had to clean my MAF sensor.

I knew this was the problem when I saw the K&N as I use to be a tech and had to do the same thing to other customers vehicles where the engine light was not on but there were running issues.

It was not oil on the MAF but a thin layer of dirt/dust. It does not take much to make the MAF sensor not read right. Auto makers have even put out TSBs and other memos about K&N type filters and damage done to MAF sensors and that it would not be covered by warranty.

EDIT
Another example is my old B4000 truck I bought. It was not running well when I got it. I did all the same fixs I did to my Corvette but still was there. I removed the MAF sensor and cleaned it. It was as bad as my Corvette. It did not have a K&N but did have over 150k on the MAF. My Corvette had less then 20k, maybe less then 10k, on the K&N and showed similar dirt. So dirt will get to a MAF sensor with either filter but K&N lets a lot more in and takes less time to clog up a MAF sensor.
Also got my truck real cheap as the guy could not find anybody that could fix it.

 

[DominionSeraph]

I have hard time believing that you will see no power increase when you remove air restriction. K&N cannot filter less, yet let in less air. The two are mutually exclusive.

Untrue.

Setting:
Long hallway.
Hardwood floors.
Fan on one end.
Somebody keeps feeding dust bunnies into fan.

Q: How reduce dust bunnies from getting to the end of hall without reducing airflow?

A: Wet floor.

Science wins. You fail.

 

[DominionSeraph]

double

 

[alphatarget1]

Looking at the report...the WIX looks like the best compromise between the two. I doubt the longevity would really be hurt by the different between WIX and ACDelco...and that is assuming the products haven't changed in 6 years...and the accuracy of the test. I'm sure you're fine.

I changed my air filter 3k miles before it was due and there were like bugs and crap trapped in it. The filter itself didn't look all that dirty but the car did run smoother after I changed it. GO figure...

 

[halik]

Untrue.

Setting:
Long hallway.
Hardwood floors.
Fan on one end.
Somebody keeps feeding dust bunnies into fan.

Q: How reduce dust bunnies from getting to the end of hall without reducing airflow?

A: Wet floor.

Science wins. You fail.

Err wat? Bunnies?

 

[Gillbot]

Only ones I have seen are single pulls. Even then they show maybe a couple HP and even then its at the very peak and torque shows little to no diff. as well.

Heres one...

http://forums.tdiclub.com/showthread.php?p=2987755

The K&N pulled .07 more HP. Well within the margin for a dyno.

I did about 30-50 pulls while tuning my car over an entire day. We did a full tuning session with the K&N then a full tuning session using a cheap-o Fram paper and guess what, max power came with the paper filter installed though the difference was less than 2-3hp OVERALL after we had everything dialed in. IMHO, 2-3HP is well within margin of error of any Dyno.

Now couple the above power figures with the fact that you could see the evidence of decreased filtration on my intake tract, that's all the data I needed to yank the K&N for good. Plus the fact that I do oil testing and could see the decrease in particle count after the K&N was removed, yeah, I think that sums it up. Well, for me at least.

Now i'll go get my Flame Suit ready for K&N to return again!

 

[halik]

How is it user error. The old owner of my car got filter, put in car, and drove. It had less then 20k on it when I took it out and had to clean my MAF sensor.

I knew this was the problem when I saw the K&N as I use to be a tech and had to do the same thing to other customers vehicles where the engine light was not on but there were running issues.

It was not oil on the MAF but a thin layer of dirt/dust. It does not take much to make the MAF sensor not read right. Auto makers have even put out TSBs and other memos about K&N type filters and damage done to MAF sensors and that it would not be covered by warranty.

Do you offroad a lot? I never had problems with oil or dust, but I suspect that if you just pop it on the car, you'll end up with oil and subsequently dust on the MAF. I always dab them with paper towel before installing and my MAFs are sparkling clean.

 

[Gillbot]

Do you offroad a lot? I never had problems with oil or dust, but I suspect that if you just pop it on the car, you'll end up with oil and subsequently dust on the MAF. I always dab them with paper towel before installing and my MAFs are sparkling clean.

Not every one who changes an air filter is aware that they shouldn't just "pop them in" and thus, there are many out there with problems. It's VERY common.

 

[halik]

Not every one who changes an air filter is aware that they shouldn't just "pop them in" and thus, there are many out there with problems. It's VERY common.

Oh totally agree,
all those MAF related CELs come from somewhere.

 

[Gillbot]

Oh totally agree,
all those MAF related CELs come from somewhere.

That's part of my gripe with K&N and other "performance" related companies. They prey on the misinformed. Now, I'm all about one doing research on their own but selling a product without typical disclaimers is crazy. Just like many oil companies claiming their product is good for 25,000 miles. You know someone is gonna toss that in, go trucking through the desert and wonder why their engine seized up!

 

[JulesMaximus]

Not every one who changes an air filter is aware that they shouldn't just "pop them in" and thus, there are many out there with problems. It's VERY common.

Aren't K&N filters advertised as direct replacements for OEM filters? Meaning you simply open the airbox, remove the old filter, insert the K&N and that's it? That was always my understanding. I put one in my wife's 325i years ago and it was running poorly and threw a CEL. I took it out and put the paper one back in and the car ran fine.

 

[alkemyst]

http://www.mkiv.com/techarticles/filters_test/2/

 

[Gillbot]

Aren't K&N filters advertised as direct replacements for OEM filters? Meaning you simply open the airbox, remove the old filter, insert the K&N and that's it? That was always my understanding. I put one in my wife's 325i years ago and it was running poorly and threw a CEL. I took it out and put the paper one back in and the car ran fine.

Yes, hence my gripe. Plus their better power and more MPG claims. D:

 

[Vette73]

Do you offroad a lot? I never had problems with oil or dust, but I suspect that if you just pop it on the car, you'll end up with oil and subsequently dust on the MAF. I always dab them with paper towel before installing and my MAFs are sparkling clean.

Ha, no its a 2wd kingcab Mazda B4000. Only "offroad" work it gets is when i park it in my backyard.
Old but just runs in town moving things for family or hauling junk to the trash yard.

 

[halik]

Ha, no its a 2wd kingcab Mazda B4000. Only "offroad" work it gets is when i park it in my backyard.
Old but just runs in town moving things for family or hauling junk to the trash yard.

Ah,
neither one of my cars leave city or highway in between cities, so I've had zero issues with dust and crap like that. Plus we don't get a whole lot of dust storms in midwest...

 

[Throckmorton]

Because it was probably user error. Like I said, I've had no issues with mine and the same can be said for my old "ricer" that had a K&N cone filter.

No matter what, the K&N is letting less dirt in than a paper filter. Why not just run no filter at all? I doubt you'll have any real problems.

 

[Howard]

No matter what, the K&N is letting less dirt in than a paper filter. Why not just run no filter at all? I doubt you'll have any real problems.

Less?

 

[Throckmorton]

Err, MORE dirt

 

[JulesMaximus]

Yes, hence my gripe. Plus their better power and more MPG claims. D:

Yeah, the mpg claim is pure bullshit. HP? Probably also bullshit.