Foam filters and their Cotton Gauze cousins...
 

I know many of you feel that foam filters are inferior in flow and filtering capabilities compared to the popular "K&N" cotton gauze filters. Considering K&N's long standing history, and good track record, I can understand why it is so easy for many of you to just automatically discount any other designs. I did a quick little experiment with a cotton gauze filter I had here, and one of our new Secret Weapon filters, just show the real differences here, and why we here at at Weapon*R, and a number of other companies (Comptech, True Flow, etc) feel that a foam filter is a better option. The experiment conducted here is in no way to be considered scientific, an independant test will be conducted in the near future for an accurate measurement of filtering capabilites. This is merely to just give everyone something to ponder when they make their filter choices.

http://www.weapon-r.com/store/agora....&ppinc=search2

To me the only good thing about the secret weapon filter is the integrated velocity stack that is nice . I still dislike the majority of foam filters as well as most weapon r products . sorry that's just how i feel but kudos x 3 to the designer that added the velocity stack to your new filter design

I don't want to discredit your product, but that test really doesn't prove much.

Unless you can provide is with actual tests in dirt filtering and not just an observation in differences between your filter and a generic 5 dollar filter from Kragen, I'm not convinced.

Here's an article with a more conclusive test on 4 types of performance filters

Foam will "Out Filter" Cotton but flows very poorly, The best Air Filter on the Market today for filtering and flow is the Green High Performance air filter, 2nd is the K&N

As I stated in both my post and the article, this is not meant to be scientific, and that an actual dirt filtering test done independently will be coming in the near future. The actual cotton gauze filter used was an AEM unit, not a generic. And in regards to the comment about foam flowing poorly, our Secret Weapon Filter was flowbenched by Banks Power at 800cfm, while K&N's filter claims 881cfm for standard round filter. While our filter is slightly lower, we believe it's a good trade off for better filtering.

you gonna do a bench flow on the filters?

Im all for the foam filters, I had an HKS Super Mega Flow filter on my Accord and I loved it. I never did any professional tests on it, but it did replace my AEM filter and I felt ther was a better air flow and the filter got dirty quick which means it was stopping dirt from getting into my engine ... My AEM was on my car for 8 months and didn't look to dirty once I removed it ... My HKS had to be cleaned monthly!

I was under the impression the Apexi filter was #1. Infact it's even an oilless filter.

it goes apexi , k&n style cotton gauze and then paper then foam , as far as flow anyways.

What I though, but couldn't find the review.

not sold.... need flow test and filtration tests

This study is interesting.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

Got soemthing to back that up ... Was there a flow test done?

It's from my memory and i believe it was from bence flow testing done a year or two back by import tuner i believe.

this was posted on the boards here a little while back.... i think it's a pretty good article.

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

Yeah, that's the test I was referring too. Good find/refind.

I like the Apexi. Use one on my CAI installed on our 02 Alitima and it is nice. Little shake, shake, shake. Hoseher down adn let dry. Done.

No oils to possible glog up the MAF sensor. No extra cleaning products to buy.

you guys realize that m-flo linked the same article in his post the whole time right? lol...

I guess that's what happens when you don't make it apparent its a link.

But yeah we are all pretty much basing our thoughts on the same article.

Seeing as its only one article I'm open to seeing other tests showing different results... but I have yet to see any..

WeaponR_ray can you run a similiar test pitting your filter against the K&N and/or Apexi?
well an independent third party test would be preferable but still... Such a test would go a long way to proving your claims...

I too like the integrated velocity stack... speaking of which
did you guys finish the redesign of the secret weapon intake for the xA/xB?

A comparison test for flow and dirt filtering against other brands may come later. EvilDave is testing our current redesign of the Secret Weapon for the xA/xB.

Yeah but will the scret weapon ever be carb approved? whats the estimated gain?

Here are a few other companies that also offer foam filters, and their tests against other types of filters. The CARB approval on the Secret Weapon filters is still pending, and waiting on word from the state. We have sent all the information they requested, and the process is out of our hands.

AMSOIL FILTERS:
http://www.performanceoiltechnology....ir_filters.htm

TRUE FLOW FILTERS:
http://www.sporttruckdirect.com/True_Flow.html

INDEPENDENT TEST:
http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

Darren, there will be a dyno test run to compare a couple of intakes.

Whats the gain? Ask Brad how my car pulls now.

hmm i'm very very sceptical

actually I don't really have time to go into that much but those links.. well
a) they don't really match up
b) the first two are propaganda (the first link makes some claims which don't seem to bear out in the 3rd link's independant study). The second link doesn't seem to have much in the way of evidence.
c) realistically, yes if you used a thick enough piece of foam, obviously you would have better filtration and dirt capacity... but you are trading off air flow obviously.

Those links do show that foam MAY have the potential to be better. BUT, when it comes down to it it really seems to depend on design and basically what the engine and filter looks like.

But I am skeptical about the validity of all three pages (I'm not skeptical about the results of the independent study, but simply skeptical about how far the results can be applied).

I'll back up my statements based on the links themselves at some later post...

I will be at the State College Show, and I will bring a Filter Flow Machine with me any one who would like to test some filters..look up Rick (me) at the More Than Tires tent.

hey... post up the results of your test please... whenever it happens.. I dont know when the state college show is supposed to take place.

As promised this is my more detailed analysis of the articles presented in favor of foam filters:

Before I start however, I would just like the point out what the issue at hand is:
The issue isn't whether or not foam filters CAN provide better filtering, its whether foam filters can provide at LEAST the same amount of filtering as gauze filters while providing the same airflow.

Article 1: Amsoil page

I'm going to read between the lines here and say this statement more or less says.. that their foam filter won't provide the same amount or airflow.

The problem here is, this statement somewhat invalidates this article for comparing Foam vs. Gauze. Why? b/c we are not trying to determine if the foam AMSOIL filter is better b/c of the oil they use...

Again, we are presented with the same argument as before (our product doesn't provide as much airflow, but better filtering).

...and then they procede to contradict themselves in the very next sentence. Unless you read that as just "airflow capabilities" and not "superior airflow capabilities." My other problem with this statement is... well its simply not true. Well at least according to article 3 (the ISO 5011 comparison article)... Of all the filters tested, the AMSOIL filter reached maximum airflow restriction the fastest... meaning a shorter time than even the K&N... (the fifth chart down on the ISO 5011 article... lasted 20 minutes compared to 24 for the K&N)

I won't refute this, this may or may not be true.. shrug... but I will point out... they are once again conceding airflow.

Sure, I'm willing to believe that it IS.. the question is what is the trade-off? Airflow?

I'm going to nit pick a bit here and say... the numbers don't match up with the results shown in Article 3. In fact the AMSOIL filter is shown to have to LOWEST dirt capacity of all the filters (2nd chart in Article 3, the iso 5011 article). I'm not saying they're lying.. but different types of testing... and possibly different filters... Still though I see a lot of the page as a lot of marketing hype, and very little in the way of concrete evidence.

So in conclusion... this page basically told me:
Foam CAN filter better than gauze... but the trade-off is airflow.

Article 2: Trueflow page

I'm not going to quote anything here since there really isn't much they said. They claim better dirt filtering... but not necessarily better airflow. They claim "better airflow when dirty" but that could be a lot of things...
better airflow than a saturated gauze filter?
Anyhow this page is pure marketing... yes the filter is nice and thick.. but doesn't that just mean... worse airflow?

Anyhow that's all for today i'll talk about the third article some other time..
but my final point would be... all these filters are for large motors, i.e. trucks.... our poor 1.5L engines need all the help they can get... can they really afford to sacrifice airflow?

sounds so delicious! Thanks