Air filter test results

[DustenT]

This might be a repost, but for all the n00bs that want to install cold air intakes, you should look at these test results:

http://home.usadatanet.net/%7Ejbploc...011/SPICER.htm

K&N filters (and aftermarket cone filters in general) are terrible at filtering. I also read that installing a K&N filter will decrease the life expectancy of a motor by 15%.

Just thought you should know.

[Severian]

It's an interesting report, but if I were an AC Delco representative I could not have created a better piece of marketing material myself. The first graphic on the page made me scoff a bit...the delta between K&N and AC Delco is 3%, but the graph is one of those that makes the delta look HUGE. I hate graphs like this; their only purpose is really to deceive. Just give the numbers in a case like this because the differentials are so small.

http://home.usadatanet.net/%7Ejbploc...s/image001.png

None of the other graphs on the page are as offensive though.

[DustenT]

Originally Posted by Severian

It's an interesting report, but if I were an AC Delco representative I could not have created a better piece of marketing material myself. The first graphic on the page made me scoff a bit...the delta between K&N and AC Delco is 3%, but the graph is one of those that makes the delta look HUGE. I hate graphs like this; their only purpose is really to deceive. Just give the numbers in a case like this because the differentials are so small.

http://home.usadatanet.net/%7Ejbploc...s/image001.png

None of the other graphs on the page are as offensive though.

Did you read the last section of the report? It isn't marketing material. As for the graph, please post a pic of what you think it should look like. When the spread is only 5%, of course it's going to look like that. I assumed everyone was capable of reading the scale.

Final section, explaining the report in detail:

The Story behind the test:



First of all, many thanks to Arlen Spicer and Ken at Testand for organizing and facilitating the test. Arlen is a professional Firefighter who also operates a small tree service on the side. The tree service is the reason he owns a diesel truck. This study was the result of nearly a year of work by Arlen to get accurate independent data on air filters for the GM Duramax Diesel. Arlen originally set out to build his own Filter Test Stand so that he could perform accurate, repeatable and independent measurements on the various filters available for the Duramax. Arlen questioned the claims made by aftermarket filter manufacturers that their filters were superior to the conventional OEM style paper filters. After spending many months, hours and a considerable amount of his own money, he learned first hand how difficult it was to perform an accurate air filter test. He found it was difficult to maintain all the necessary controls to insure an accurate measurement. It was at this juncture that Arlen received a call from Ken at Testand offering to perform the ISO 5011 test free of charge. Ken found Arlen’s idea for an independent comparison study very interesting and offered to do the ISO 5011 testing using one of Testand’s industrial Filter Test Machines. Arlen posted the news on the Internet and immediately offers from other Duramax owners to purchase and send filters for the test started rolling in. Some purchased and donated filters and others made contributions to cover the expenses and the cost of shipping the filters to Teststand. It was truly a team effort. The end result is the top quality data presented in this report. The following is a quote from Arlen.



(Arlen) SPICER wrote,

“Now that I am not doing the tests and my objectivity is not necessary, let me explain my motivation. The reason I started this crusade was that I was seeing people spend a lot of money on aftermarket filters based on the word of a salesperson or based on the misleading, incomplete or outright deceiving information printed on boxes and in sales literature. Gentlemen and Ladies, Marketing and the lure of profit is VERY POWERFUL! It is amazing how many people believe that better airflow = more power! Unless you have modifications out the wazoo, a more porous filter will just dirty your oil! Some will say " I have used aftermarket brand X for XXX # years with no problems. The PROBLEM is you spent a chunk of ching on a product that not only DID NOT increase your horsepower, but also let in a lot of dirt while doing it! Now how much is a lot? ANY MORE THAN NECESSARY is TOO MUCH!

Others are persuaded by the claims of aftermarket manufacturers that their filters filter dirt "better than any other filter on the market." Sounds very enticing. To small timers like you and me, spending $1500 to test a filter sounds like a lot. But if you were a filter manufacturer and you believed your filter could filter dirt better than any other media on the market, wouldn't you want to prove it? Guess what. Test your filter vs. the OE paper. It will cost you $3000 and for that price you will have the data that you can use in your advertisements. Your investment will be returned a thousand fold! EASIER than shooting fish in a barrel! So why don't these manufacturers do this? Hmmm? Probably not because they would feel guilty about taking more market share.



Now I am not saying that ALL aftermarket filters are useless. A paper filter does not do well if directly wetted or muddy. 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. Now how many of our trucks collapse their filters from mud and water? However, if a filter is using "better airflow" as their marketing tool, remember this....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. And this remains true until the filter is dirty enough to trip the air filter life indicator. At that point performance will decline somewhat. Replace the filter and get on with it.

Hopefully the results of this test will do 2 things. Shed some light on the misleading marketing claims of some aftermarket manufacturers and/or give us new insight on products already on the market that are superior to our OE filter. I stand for truth and will eat my words publicly if my statements prove wrong. I appreciate all of the help and support that you members have offered in this project. It would simply be impossible without your help. A huge thanks to Ken at Testand for his willingness to take on this project. I would be spinning my wheels from here to eternity without his help… SPICER”



Our thanks to Arlen and Ken for making the test happen and providing the valuable test results for the benefit of all.

[KetteringTi]

This seems kinda irrelevant... The big issue for us is the flow of the airbox itself. A "cold-air" pipe-style intake is going to flow better regardless of the filter. Only problem is, you can't put a paper filter on an intake that lacks an airbox, so naturally ppl are going to bite the bullet and take the 3% less filtration.

[DustenT]

Originally Posted by KetteringTi

This seems kinda irrelevant... The big issue for us is the flow of the airbox itself. A "cold-air" pipe-style intake is going to flow better regardless of the filter. Only problem is, you can't put a paper filter on an intake that lacks an airbox, so naturally ppl are going to bite the bullet and take the 3% less filtration.

How do you know there is an air flow issue with the factory air box? I'm pretty sure BMW did the math on the air box.

This is why nobody sees a power increase when they install their CAIs, the car is a lot louder, but power does not increase. Is the added noise and dirt worth the 1hp gain, not to mention the $200 you pay for the CAI? That is the question.

[Severian]

Dusten there's no need to get territorial unless you wrote the thing. Plus I want to stress that I never said it was marketing material...I said that if I worked for AC Delco I could not have created better marketing material. Assuming it's truly an unbiased report then that's what would make it awesome marketing material.

I think a graph to show a 3% span is silly. Graphs are good at illustrating large differences in value; for small values you should just give the numbers. Otherwise it comes off like you're trying to cloud the issue (even if you're not trying to).

Like I said though, it's informative. I just nitpicked at how the graph looked like AC Delco marketing material. I didn't say it was.

Ugh, I've written enough.

[SnowTech.3]

Take that with a HUGE grain of salt.

Were the K&N & UNI filters tested oiled or un-oiled? That is integral to their ability to trap dirt. Now, I am not a K&N proponant or anything, other than the fact it allows a lifetime filter.

I also don't buy into the accumulative dirt capacity chart - K&Ns dirty, can still flow effectively enough for the engine to run, while in similar off-road situations, paper will clog completely and kill the engine. The measurement of accumulative capacity is listed as "Initial restriction + 10" H2O" Maybe at 10 inches of water over the initial restriction, the K&N still flows better than many of the other filters, so it might have much greater dirt holding ability.

Even if it doesn't hold as much dirt - you remove it, wash it and reinstall it. You can do that as often as your conditions require. THAT is the attraction to me to lifetime filters, though I admit to liking foam UNI filters much more than oiled cotton gauze like K&N.

Some of the cold-air-intakes that were introduced years ago produced large gains. Because of the filter? No, because the airbox designs were inherently restrictive. Back when I was doing flow-bench work at a VW-Porsche shop in college, I spent weeks playing with intakes and filters just because I was curious. In some applications, an aftermarket filter by itself MIGHT show a gain, but it is rare. In some applications, the filter change makes zero gains at all, and it is the airbox design that is the restriction. In my experience, a good quality paper filter (WIX or Mann were good I think) will flow just as much or more than a K&N dry, and more than if it is oiled.

But in a Cummins or a Honda or something else, the opposite may be true. This is my experience, that web site is someone elses, though it has pretty graphs and expensive equipment.

[DustenT]

Originally Posted by Severian

Dusten there's no need to get territorial unless you wrote the thing.

Sorry, I didn't mean for it to sound that way.

I'm just trying to post some informative material. I did some damage to my supercharger (on top of the alcohol injection problems) and I think it had something to do with a K&N filter and a CAI.

[KetteringTi]

I was talking about factory airboxes vs. pipe-style intakes in general.

[Severian]

Hey this is actually on topic of dust, air filters, and such. I changed our Z3 and 318 air filters recently and the #1 ingredient I found in the filters? That foam stuff that's apparently supposed to muffle the sound of the intake. It was below the filter and disintigrating in both cars...weird.

[DustenT]

Originally Posted by Severian

Hey this is actually on topic of dust, air filters, and such. I changed our Z3 and 318 air filters recently and the #1 ingredient I found in the filters? That foam stuff that's apparently supposed to muffle the sound of the intake. It was below the filter and disintigrating in both cars...weird.

I found the same thing.

[DeadpaN]

Well I've been considering an aftermarket filter upgrade for some time now, and I must say if anything, after seeing that data I'm definately going with an aFe filter from Bavauto. Way better specs than K&N.

[PeteN95]

Mine had a K&N type CAI on it when I got it. I've heard that oil from the filter can affect the MAF sensor? I was considering getting one of these for a replacement, the specs look good:

http://www.aempower.com/press_events_detail.asp?aid=58

[aceyx]

I've never really understood CAI in a BMW. The stock airbox pulls from behind the kidneys, and the only heat exchange that occurs is from the tube running over one of the radiator tubes.

The engine is sucking in a lot more air than is actually getting "pushed" in, especially in the case where the cone filter is behind a headlight.


In any event, between two filters with the same ability to catch dust, the one that flows more air will also let more dust in. I think there was a discussion like this on the Z3 forum, but certainly not any type of scientific process like the one posted.