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AirFilter(Foam vs Cotton Gauze)AIR FLOW VS. FILTRATION EFFICIENCY
I was a big fan of K&N filter but here is text that i read made me think different: visit this website and you will find everything you need to know on how to protect your engine.
the text below is copyright by: TheMotorOilSite.com High Efficiency Filtration When speaking of high efficiency filtration, I am referring mainly to oil and air filtration. Other areas of filtration are important, but none more so than these two when it comes to engine protection and performance. Your air filter is the guardian of your engine. It stands at the gates of your engine's air intake and wards off renegade dirt particles that want to wage war on your engine. The question is, who do you want standing at the gates, your best soldier or some guy who was just promoted from "boot boy"? I think the answer is clear. So, as opposed to the standard paper filter that we're all so familiar with, consider an alternative air filtration device which is more like a sponge (actually, it's foam). Because foam is "squishy" it can be made slightly larger than the air intake compartment so that when installed it fits very snug with no room for air to by-pass the filtration unit. In addition, it has millions of "tiny" channels through which air can flow, but these channels are not straight channels. They twist and turn through the filtration media. Air can pass through easily because these "tiny" channels are actually much larger than the channels through the paper filter we just discussed. This is possible because the paper filter only has one chance to get the dirt. This foam media has multiple opportunities to catch the dirt. You see, as the air travels through these winding channels, it can turn this way and that with ease. However, the dirt particles that the air is carrying travel in a straight line until they hit something. Obviously, at every turn, the debris within the air hits a "wall". You say, "Well, that's great, but why doesn't that dirt just bounce off the wall and keep right on going?" Good point. I tell you what, why don't we put a tacky substance in the foam so that when debris hits these "walls" it's stuck there like a fly to one of those sticky tapes. You say, "Yeah, that would work!" Not only will it work, it will work far better than the paper air filter discussed above. Because of the depth-type nature of the foam filter AND the added tack oil, it will remove MUCH more dirt and MUCH smaller dirt particles. Now, we've established that such a filtration media would seal up the intake compartment, should have better air flow, and we've established that it has more opportunities to catch the dirt, so less dirt makes it into the engine. The next question should be, will it hold as much dirt as the paper filter? Well, of course it will. It's much thicker than a paper filter, and, because of the nature of the foam media, has a virtually limitless surface area over which to collect dirt. In fact, the more dirt it collects, the better the filtration (with minimal reduction in air flow). It's also much more durable than paper, so it NEVER needs to be replaced. Just wash it once a year, re-oil it and put it back in the vehicle. WHERE CAN A PERSON GET ONE OF THESE? Well, there are a number of companies out there that produce these foam filters, but many of them only produce them for motorcycle type applications. There are, of course, new companies sprouting up all the time with new filtration ideas or reworked old ideas, so some research might turn up a few I haven't yet heard of. AIR FILTRATION One company that I know produces these filters for automotive type applications is AMSOIL. They are a lifetime filter (guaranteed for the life of the vehicle) and must be washed with soap and water and reoiled about once per year. They've been producing these filters for quite a long time now. ITG also makes a foam air filter. It is not washable/reusable, but I have to assume it has similar filtration and air flow characteristics to the AMSOIL filter line. The ITG line includes filters for many small engine applications as well. AMSOIL air filters mainly apply to automotive applications. The Amsoil foam filter has been tested on the industry standard SAE J726C test procedure and is shown to provide significant air flow and filtration efficiency increase over other air filter types. I haven't seen J726C test data on the ITG, so I'll focus on the AMSOIL filters at this point. Take a look at the ITG website for more info on these filters. There are filters to fit most vehicles, although some have to be special ordered. If there isn't one to fit and you can't find another manufacturer that makes a similar type filter, try getting a paper filter with a foam wrap. This will at least help somewhat. Well, most of us know the most well known brand of cotton gauze filter. We'll call them "Brand X". Well, Brand X, appears to have pretty good air flow characteristics, at least significantly better than pleated paper filters. Also, their filters are guaranteed to last for 1,000,000 miles or 10 years - far longer than a paper air filter ever could. As a result, even though you pay quite a bit for them, you'll probably spend less over the life of your vehicle than you would on paper filters. I do find it somewhat comical, though, that their warranty covers their air filters for 1,000,000 miles or 10 years. That's 100,000 miles per year. How many people do you know that can drive that many miles in a year? Most people won't get much more than 200,000 miles out of a Brand X filter under a 10 year warranty. Granted, that's still quite a long time and would offer significant long-term savings over conventional air filter purchases. But, you have to admit, it's not REALLY a 1,000,000 mile warranty for 99% of vehicle owners - most people will never drive that far. It's a marketing tactic, and a fairly good one, I have to admit. AIR FLOW VS. FILTRATION EFFICIENCY Brand X filters DO seem to provide enhanced air flow to your engine, thereby increasing horsepower. You wouldn't find so many racing engines using them if they didn't. So, if you're looking for performance, Brand X does offer that. In addition, they have kits for modifying your air box to provide even more air flow, as opposed to just using a drop in filter. Again, for performance minded folks, this is a bonus, I suppose. Unfortunately, I find no conclusive evidence that a Brand X filter has any better filtration efficiency than a typical paper air filter element. In fact, until very recently (early 2002) there was no reference to filtration efficiency testing on ANY Brand X website I had been to - weather the company site or a distributor site. I suppose that doesn't necessarily mean the data didn't exist, but if Brand X filters provide better filtration efficiency, why wouldn't it say so in their literature. It only makes good sense to publish positive information about such an important benefit. If I sold Brand X filters, I'd certainly be mentioning it, wouldn't you? The truth is, although they talk incessantly about increased air flow and horsepower, any past reference I've ever seen to Brand X filtration efficiency stated something similar to: "Brand X developed an oil WHAT ABOUT COTTON GAUZE FILTERS? impregnated cotton air filter gauze which exceeds the minimum filtration standards". That's not too impressive to me. Standard paper filter elements achieve that. They basically have to in order to be sold in stores. And, although Brand X indicates that the filtration efficiency of their filters increases as they collect dirt, so does the efficiency of paper filters. Paper just happens to lose air flow much more quickly. Important News Regarding "Brand X" Filters As of March 2002, Brand X appears to have testing data on their website which indicates an initial efficiency of approximately 97% and a cumulative efficiency of just slightly over 99% on the SAE J726 air filter test. Of course, Brand X wants to brag about these results, but I'd like to make note of a few important issues. First, the test data is from 1999. Now, I'm not saying that makes the information dated. If there have been no changes to the Brand X filter construction since then, the data is still valid. However, if the data has been around since '99, why is it just being published now? If it shows their filter to be so wonderful, wouldn't it have made sense to publish it back in '99, when the tests were run? Second, the J726 test is only useful when put into context. Many variables within the testing parameters are adjustable depending upon the application the filter is being tested for, etc. For instance, there are two different air boxes that can be used on this test which could yield different efficiency numbers for the exact same filter. In addition, you're not required to use the same contaminant every time you run the test. Not only is there the option of using either AC Test Dust or Glass Beads, but you can also choose the micron levels to test at. With glass bead testing, you can get very specific and only test beads of a very narrow micron range if you like. With AC Test Dust, there are numerous different "grades" of dust you can use which range from extremely coarse to extremely fine. A "coarse" AC Test Dust will have very few particles under 20 microns, whereas a fine test dust will have a very high percentage of particulate matter under 20 microns. Although in years past many J726 tests were being run with coarse test dust, this trend is changing. Since it's been established that the majority of automotive engine wear is caused by particles in the 5 to 20 micron range, more and more of these J726 tests are now being run with fine test dust so as to more closely approximate the conditions the filter will encounter when in consumer vehicles. So, I find the new Brand X filter test data to be of little use in the grand scheme of things. First, they've used the coarse grade test dust which doesn't really tell us how well the filter will remove the particles which are most damaging to your engine. Second, since there is no way to guarantee that other filter manufacturers have used the same parameters for their J726 tests, there is no way to compare the Brand X results to other manufacturers' test results. If Brand X wanted to show their filter superior to other filters, they would have had their independent lab run the J726 on comperable competing filters using the exact same testing paramaters that were used on their filter. Then, at least you could see a side by side listing of efficiencies using the same testing specifications. In addition, if they wanted to show real world performance of their filters, they would have used fine grade test dust so the testing more accurately reflected actual engine conditions seen by most vehicles. And, just for comparisons sake, I did an Internet search for J726 test data on pleated paper filters. I didn't find much, but I did find a couple filters with test data. Each showed initial efficiencies of just over 99% and cumulative efficiencies approaching 100%. Of course, testing for other pleated paper filters might not be as good, but these results are better than the Brand X filter results. I could do some more research and make some phone calls to determine if these tests were run with coarse or fine AC Test Dust, but either way, the results are better than the Brand X results. And, if they were run with fine test dust, then the filtration efficiency of these filters seems significantly better than the Brand X filters tested. Now, please remember, any comments I've made about the Brand X filters are my opinion only. But that opinion is based upon the information available, provided both by Brand X and other manufacturers. In addition, I've seen J726 testing which actually did pit the Brand X filter up against two comparable filters (one foam and one traditional pleated paper) using the same J726 test parameters for all filters. The Brand X didn't fare very well in this test. Do I know that those results weren't tampered with? No. Do I know the Brand X results weren't tampered with? No. I have also seen more recent testing comparing the Brand X filter to comparable paper and foam filters using identical test parameters which shows the Brand X getting stomped by both filters in the efficiency category. However, it is important to note that this testing was not based upon the J726 test parameters. It was a more simplified testing apparatus. But, the logic behind the test seems sound, and all parameters were kept the same for each filter. Take this information with a grain of salt and do some of your own research into this area. All I'm trying to say is that you might want to give a little more thought to using something other than Brand X if your concern is engine protection. I have my doubts as to whether the Brand X filter line will serve you as well in this category as a paper filter. Do I have conclusive proof? No. Do I have sufficient evidence to point in that direction? I think so. SO WHAT. BETTER AIR FLOW - NEARLY EQUAL FILTRATION Of course, you might say, "So, what. If I can increase my performance by increasing air flow, while still maintaining nearly the same filtration efficiency, I'm still better off. Besides, I won't have to replace my air filter every 10 to 20,000 miles. Sounds like a good deal to me." At first glance, that might seem to be the case. However, let's discuss what I said earlier in this chapter about the relationship between air flow, filtration efficiency and engine wear. I think you'll see the potential problem that I'm focused on. MAKING SENSE OF AIR FLOW & FILTRATION Let's just assume that there are 10 grams of dirt sized 20 microns ("coarse" test dust size) or greater per 10,000 gallons of air that enters your engine. And let's also assume the engine receives about 10,000 gallons of air every half hour. It could be any ratio of air vs. dirt, it really doesn't matter for the purposes of this discussion. It's the comparison percentages that matter. If the numbers above are assumed, let's also assume that a paper element is 99 percent efficient at removing particles of 20 microns or larger (J726 test data suggests that). It then stands to reason that every hour, 9.9 grams of dirt particles (99% of 10 grams) would be filtered out and 0.1 grams would be allowed to enter your engine. Now, let's assume that the Brand X filter provides just 10% greater air flow than a paper filter, but the same filtration efficiency. That means that over the same hour, 11,000 gallons of air would enter the Brand X equipped engine (10% more air than the paper filter). According to the assumptions made above, there would be 11 grams of dirt over 20 microns within this amount of air (at 10 grams per 10,000 gallons of air). At 99% efficiency (the same as the paper element), over the same one hour time period, 10.89 grams of dirt would be trapped by the filter and .11 grams would enter the engine. Now, that might not seem like much of a difference, .1 grams to .11 grams, but consider it as a percentage. That would be 10% more dirt entering your engine! Of course, when you think about it, that only makes sense. 10% better air flow with no real increase in filtration efficiency SHOULD lead to 10% more dirt in your engine. IS THAT A BEST OR WORST CASE SCENARIO? The Brand X website actually claims at least 50% more air flow than traditional paper air filters and the J726 test data suggests that, at best, Brand X offers slightly lower filtration efficiency than traditional pleated paper filters. So, I would say the numbers above are very conservative and indicate what I would consider to be a best case scenario using Brand X filters. ARE YOU SCIENTIFICALLY CERTAIN OF THIS? No. I should make it clear that I don't have any scientific studies on Brand X filters to indicate increased engine wear (although I have caught wind of some oil analysis testing which showed increased levels of "dirt" in an engine after a switch to Brand X). I also can't say with absolute certainty that Brand X filters don't have better filtration efficiency than a paper filter, since I don't have any recent J726 testing that compares them using the same test parameters. However, based upon the evidence I do have, I'd say it's likely that, at best, they filter almost as well as a traditional pleated paper filter. So, if that's the case, no matter how much the Brand X filter increases air flow, the potential for engine wear would seem to increase just as much. If Brand X only gives a 5% increase in air flow, then you'll only see the potential for 5% more engine wear. But, if you only acheived 5% better air flow, is it even worth it? How about a 30% increase in air flow (which is unlikely in real world applications)? Is a potential 30% increase in performance worth the potential for increased engine wear? Not in my car.
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:1992 Pearl LS-L :182,000 (5/2010) – 210,000 (1/2013) :MOD :Raybestio STS front rotors :Green air filter :Aero resonator :Magnafow muffler/dual tips :RE970 tires DONATED :92 Claret SVX OTHER :07 Scion tC (wife) RIP :94 Blk Mustang GT :89 Slv 240SX |
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Might I also interest you in this set of knives that NEVER, that's right, NEVER need sharpening....You say, "Mike, how can you cut through a boot and still slice a tomato paper thin?" Well folks the secret is in the Pterodactyl Ethelmermalate finish on these knives...They slice, they dice....
Interesting read, but a bit too gimmicky sounding for me...
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-Mike '92 Pearl LS-L (sans Spoiler) #0993 Mfg. 5/91 "It says here, 'Breakfast any time'... That's right... In that case, I'll have the pancakes in the Age of Enlightenment..." Last edited by Whoru465; 12-01-2004 at 11:01 AM. |
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I will have to read this book later neighbor
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Kayvon 92' SVX www.sounddomain.com/id/kayvon |
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More rationalization than fact in that. Sounds like it came from an Amsoil advertisement.
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
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I helped a friend put a supercharger on his Toyota T-100. When we pulled his intake manifold off the inside was coated with a very fine layer of grit. It was almost like super fine silica sand. Needless to say he was using a K&N filter. It was the stock replacement flat panel type. He is very meticulous with what he does to his truck and was shocked to see the grit in his intake. He now uses the Toyota filters. After seeing that I pulled the K&N out of my Rover. I could hold mine up to a light see small holes in it. Maybe thats why if flows more air. I've heard other people say they were designed for racing and airflow was more important than engine life because the engines were rebuilt after a season of racing anyway. Personally a few HP vs. engine longevity, I'd rather have an engine that will last longer.
Check this out. http://mkiv.com/techarticles/filters_test/2/ |
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i agree SVXASH!!! since the Subaru H6 is not a easy&cheap engine to fix like my old Ford 5.0.
and kayvon from Wheeling, hi neighbor, you are next town over! happy holidays ''
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:1992 Pearl LS-L :182,000 (5/2010) – 210,000 (1/2013) :MOD :Raybestio STS front rotors :Green air filter :Aero resonator :Magnafow muffler/dual tips :RE970 tires DONATED :92 Claret SVX OTHER :07 Scion tC (wife) RIP :94 Blk Mustang GT :89 Slv 240SX |
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I changed over from K&N to paper about two years ago. My engines are far too precious to rely on less than par filtration systems. What kills me is that lots of folks are running K&N cones that suck in hot air from the engine bay!
To each is his own! Have a good weekend. Ali
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If it ain't broken it, doesn't have enough features!!! '92 SVX LSL '03 4Runner '96 FZJ80 Landcruiser '90 Mercedes 300E |
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We've all heard the new "anti K&N" arguemnet... (i hope most have...) but the foam filter in there is rather interesting to me.. it make sense, as long as the open cell foam is a very dense foam.. i'd think that if it was dense, it would still limit airflow at least somewhat. I think its a good idea, but i'm not sold...
And the oil-MAF arguement still exists that
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Greg 97 Red SVX LSi clean 96 Black SVX LSi beater 90 Red Eclipse GSX track ho 99 Ford F250 work horse My Locker |
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Eh, Id still go with a k&n
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