No problem, I enjoy these technical discussions - they usually are a learning experience for everyone. I have a huge amount of respect for the work and experience you bring to the forum, and appreciate your participation in this discussion.

Here's a test that is almost exactly what you're looking for, conducted last year - http://www.bobistheoilguy.com/airfilter/airtest1.htm , although he only tested each filter for ~500 miles (it was one guy doing the comparison test, and he wanted to test them all during the same season and roughly similar conditions). The test was done by one of the more knowledgable members at the miata.net forums, and interestingly enough he was roundly flamed for the test being too real world, ie not managed enough with too many variables that couldn't be controlled! :p

The first hint of these concerns of mine about K&N was when I read about a test conducted by a heavy construction equipment manager who compared K&N vs. paper filters. The construction environments were extremely dusty and dirty, and he did in fact have an engine failure due to the dust passed through the K&N on the test machine (Every vehicle in the fleet had regular oil analysis records, so he documented how the oil analysis readings changed for the worse when the K&N had been in for a while). I read that test back around 1997, when I still had a K&N filter installed in my Taurus SHO - obviously I didn't like the implications of those test results, but the more I read, the more concerned I became about the reality vs. the marketing claims from K&N. The test results on Bob(is the oil guy)'s site are not unexpected to me now, and Anthony makes some realistic conclusions.

Regards,
Gordon

 

I will give you some credit here Gord. Now I've got to go out and perform my own personal tests and see how these things do. Time to break out the old homemade flowbench again!

 

What was hostile about what I wrote? No hostility is or was intended on my part.

Who exactly doesn't use any filters? I know we had some Motorola-sponsored race cars show up where I work as part of a promotion...they were a street-car-based racing class, I don't remember which...and they had K&N filters. They weren't brand new ones either :-)

jds

 

For such a lame argument, I would have expected a better answer :D

Your post stated that not only did they not filter as well (not nearly as important for a race team) BUT that it also flowed poorly as it got dirty compared with other filters. Given that flow capability would be the ONLY factor of significant interest to a race team it doesn't seem likely that they would choose a filter that didn't at least meet that requirement.

Anyway, I suppose it doesn't really refute anything. Its just a question about something which, if your position is true, doesn't seem to make much sense.

jds

 

To be honest, I was very surprised by that result (note it wasn't MY result or MY position - I just commented on the results the test achieved). I would normally expect a K&N to flow better, and to continue to flow better as it got dirty - I've never doubted that part of their marketing claims. That test raised some very interesting questions, as it seemed to be a repeatable result, with both the coarse and fine dust tests. The initial flow tests confirmed that the filter flowed better when clean, as expected.

Street racing (aka road racing, track racing, etc.)? It doesn't get that dirty, so they probably don't worry about performance of the filter when loaded, since their normal conditions would never encounter an environment to crud up a filter. Off-road racing is where the problems would be, and I'm sure lots of racers there are still using K&N (and might even still use them even if K&N didn't pay them to! ). I'd be most interested to see other independently performed runs of that same test suite.

Regards,
Gordon

 

Here are a couple of interesting and informative quotes from the test.

"A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams."

NOTE: ANYONE KNOW HOW WELL PAPER HOLDS UP WHEN IT IS WET OR MOIST? HERE IN HOUSTON WE GET ALOT OF HUMIDITY.

"Now I am not saying that ALL aftermarket filters are useless. A paper filter does not do well if directly wetted or muddy. (NOTE: THERE'S THE ANSWER!) It may collapse. This is why many off-road filters are foam. It is a compromise between filtering efficiency and protection from a collapsed filter."

NOTE: HOW OFTEN HAS YOUR FILTER COLLAPSED? Damn it Gord! Now you've got me backing you up with a comment like that! Bastard!!!

"The Flow Restriction response curves for each filter have the same basic shape. However, note how the AC Filter, which passed the smallest amount of dirt and had the highest dirt capacity and efficiency, also had the highest relative restriction to flow. The less efficient filters correspondingly had less restriction to flow. This illustrates the apparent trade-offs between optimizing a filter for dirt capturing ability and maximum airflow."

NOTE: SINCE GORD HAS GOTTEN ME TO AGREE WITH AT LEAST ONE POINT, I WILL ONLY POST WHAT IS WRITTEN IN THIS TEST. HERE IS A FOLLOWUP STATEMENT TO THE ABOVE.

"Does it flow better? At very high airflow volumes, probably. BUT, Our trucks CAN'T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give."

NOTE: I AM STILL KEEPING MY K&N ON BOTH OF MY CARS!!!

 

How about this one....?
(sorry, don´t have any more info on it...)

 

I agree with rotarygod, I myself bought the K&N typhoon sys, and love it, I did see a better gas milleage also (God know's the 8 need it). I drove (and still) have my Honda Civic SI 1991 with close to 300 000 km on it with a K&N and still work fine ....but don't take my word for it, some hate it and lots more love it !? It will always be that way ....

 

It ain't the MS one cortc and Mazda used in the MS 8. That one is just a replacement for the stock paper filter (not K&N, Gord.).

 

That filter looks like someone just stamped Mazdaspeed on top of it. There are alot of knockoffs floating around.

 

Btw if your looking for a compromise between a high filtering filter (like a baldwin) or a K&N, check out S&B.

http://www.sbfilters.com/home.htm

They're basically K&N filters, but with deeper pleats, reinforcement, and tighter meshes. Basically just a higher quality variant of a general K&N cotton gauze filter design. The biggest differences I've noticed between the two brands (having owned both), is the S&B's pleats don't bend or flex when you apply pressure, and you don't get the same "stary night" view when you hold them up to the light. They also tend to have a larger # of pleats, which extend an addition 0.5 to 1.5 inches (depending on filter) vs an equivilant K&N. More surface area = better flow and better filtration.

They also have a nice inverted cone on the bottom of the conical filters, which supposedly flows more air, but generally just results in a much louder intake. (Being that the filters aren't the restrictive part of the intake system).

There have been a number of studies showing through UOA's (used oil analysis's) that cotton gauze filters do in fact let additional dirt into the engine...but this is generally the cause of poor maintance of the filter, and not the filter itself. (Its a rather massive continuing debate) It also depends on whether your using a drop in filter, or running a full conical design which is exposed to exterior air elements. Obviously with a stock airintake system, the flow of particulate matter is already being smashed all around before it hits the actual filter element...vs an open air conical element exposed in the wheel well.

Just a suggestion for those who are looking for possible alternatives

 

Shouldn't a mazdaspeed filter come in a mazdaspeed box? Or would I be giving to much credit? If my eyes don't decieve me, it says CR performance on the box.

 

That is not an official Mazdaspeed, it's a cheap filter by some no name using the Mazdaspeed logo, ebay is full of that stuff... Including grounding kits that say Mazdaspeed and are not...

In regards to the K&N filters, they do not work and are not good for your engine... Not only do they not filter well they allow oil to coat your entire intake tract further complicating things like coating the MAF sensor and affecting it's readings...

 

I have and Injen intake on my car that uses a "K&N style" filter that uses K&N oil. I have had the intake, throttle body, and MAF sensor off of my car and wiped them out with brake cleaner. There was no oil residue anywhere on them, nor any red stains from dried oil. These filters need re-oiled because the oil dries out, not because it gets sucked through the filter into the motor. If a MAF sensor was contaminated, by oil or any substance, it would play havoc with a cars computer. All driving conditions would be effected as well as fuel economy and emissions. The contamination wouldn't just roughen up the idle.

So, like I said before, if these complaints were true K&N would not be a highly reputable and well established business. Millions of their filters have and continue to be sold. If they were as bad as some people here are claiming them to be, there would be no reason for the brand's popularity and reputation to be what it is. The only down side to oiled filters is that they don't filter as well as some other filters. But thats the trade off for better air flow. You can't have everything.

Just my 2 cents and I'm sticken by them. :D

 

I have found that haines tube socks don't filter worth a damn but Nike crew socks filter with 99.4% efficiency, but damn when the turbo spooled up it sucked that sucker right in there and fubared my compressor wheel and shaft.

 

They only pass oil if you over-oil the crap out of it. Or maybe if you oil the wrong side :D

jds

 

got the rotery extreme installed a few weeks ago. I LUVVEEEEEDDDD IT? the sound sounds like A/C and when u steppppppppppppppppp on it. ERRRR sounds like a lawn mower not quite though. even my wife said ohh my god the soiund wat did you do to it???brought it to the Mazda dealer, they said wats thats noise. and i said thats the sound of a true rotary engine. I had K&N filters all my life i swear by it

 

Glad to hear it.

Check HERE for some more awesome performance parts. On the left side of the page, click on "Performance".

 

Change your oil more often?

 

where are you in the world ? where i come from K&N filters retail at 10-15% cheaper than my local Mazda parts department .
Question:Can a huge corporation such as mazda not beat a very much smaller corporation K&N and make a better product and charge the customer more for it ?



Mod Edit: This is a 9 year thread bump, most of the people prior to this post haven't logged on in years. Many links may be broken.

 

this thread is 9 years old

 

lol, n00b and n00ber

 

You didnt read hey?

You actually are slow, it makes sense now.