The filter element should be at least three times larger than the throat, except when clamped to the end of a long runner, like with cold air intakes for EFI engines. The straighter the airflow shot into the intake tube, the less restriction there will be. In general, OEM replacement type engine air filters were less restrictive than performance filters after 200grams of dirt had been delivered to the filter. Paper filters flow more air for longer than the performance filters.
In a dyno test using his personal Subaru Crosstrek, Fenske compared four different air filters: the dirty OEM item already the car, a new OEM filter, and a cheaper aftermarket filter. Properly sized paper filters offer minimal airflow restriction unless significantly clogged. Typically, a paper filter lasts around one to two years or 15,000 to 30,000 kilometers, depending on the airflow. Even at airflows able to support over 500hp, a new normal paper air filter flows plenty of air to feed the engine.
K and N are considered the highest flow, least restrictive air filters, as long as you’re buying the premium paper filter. Clean cotton filters are typically just a bit less restrictive per square inch than paper filters. Ramair high-flow air filters are designed to bolt directly to the carburettor, eliminating the restrictive original air box. The filter itself is the same company’s low restriction paper filter and an even less restrictive oiled cloth filter.
📹 Air Filter Restriction Gauge Operation & Testing
Excerpt from Mack Truck video for air filter restriction indicator inspection and testing on trucks and diesel engines.
Do some air filters restrict airflow?
Low airflow in a home can be caused by various factors, including an air filter that is too efficient or a dirty air filter. The Minimum Efficiency Reporting Value (MERV) rating of an air filter can help determine its effectiveness. A higher MERV rating indicates fewer dust particles and contaminants that can pass through it, while a lower rating means less airborne pollutants can pass through.
To fix low airflow, it is recommended to clean or replace the air filter every 30-90 days, depending on the type of filter and the frequency of the system. High efficiency air filters may seem like the best option, but they can sometimes block too much airflow, leading to higher energy bills and potential damage to the furnace if it overheats.
To find the best air filter for your home, consider the four main types of air filters: one that removes the most airborne pollutants while allowing the HVAC system to function without strain. By understanding the four main types of air filters and their effectiveness, you can ensure your home’s airflow is optimal and your HVAC system operates efficiently.
Are air filters restrictive?
As the MERV rating increases, the filter becomes increasingly restrictive, necessitating greater pressure and energy to facilitate airflow.
Can a dirty cabin air filter restrict air flow?
A dirty, old cabin air filter can negatively impact your vehicle’s airflow, causing increased fuel consumption and increased fuel consumption. Regularly changing the filter is crucial to improve air quality and block out pollutants like pollen, brake dust, and pollutants. A PurolatorBOSS® Premium Cabin Air Filter with Febreze Freshness is an unscented solution that blocks and controls odors, leaving your car smelling fresh.
Regular filter maintenance is also necessary to prevent mold and odor-causing bacteria growth on the filter. Therefore, it’s essential to replace your cabin air filter regularly to maintain a comfortable and efficient vehicle.
Can a restricted air filter cause oil consumption?
Turbocharger damage is a significant issue in engines, as air filters are crucial for directing pressurized air into the engine. Without a functioning air filter, dirt and debris can enter the turbocharger, causing severe damage. Metal from a failed turbocharger can also enter the engine, causing complete engine failure.
Internal engine damage occurs when air is sucked in during the engine’s intake stroke, causing damage to internal engine parts like valves, pistons, and cylinder walls. This can lead to excessive oil consumption, poor engine performance, and eventual engine failure. In some cases, a restricted filter can also allow contaminants to enter the engine due to the engine’s increased work to pull in enough air.
To protect your engine from dirt and debris, it is essential to use a well-maintained air filter. Quality air filters are designed to fit your vehicle and filter out more contaminants. Regular changes are necessary to prevent contaminant buildup. Premium Guard offers high-quality automotive air filters, designed to protect your engine for up to 12, 000 miles with 99 efficiency.
Are 3M filters too restrictive?
MERV measures the efficiency of filters in filtering smaller particles (0. 3-1. 0 microns) and lower filters like MERV 8 do not efficiently filter these particles. It is crucial to replace filters with a 3M/Filtrete Micro-pleat filter to prevent dangerous airflow levels. Electrostatically charged filters work well for a week or two, but once the surface is covered by particles, the electrostatic benefit is gone. Electric air cleaners also have this issue.
It is not recommended to pay more for a feature that is only a brief benefit, as it can restrict airflow to dangerous levels. It is essential to consult with an installing contractor before using electrostatically charged filters to ensure proper duct system design.
What happens if the air filter is too dirty for adequate air to flow?
Dirty air filters can cause reduced air flow, increased energy consumption, and poor indoor air quality. As the filter becomes clogged with debris, it restricts air passage, forcing the HVAC system to work harder to distribute air. This results in higher energy bills, as the US Department of Energy states that a clogged filter can cause a 5-15 increase in energy usage. Additionally, clogged filters can exacerbate allergies and respiratory issues, especially for those with asthma or other respiratory conditions. Regularly replacing the air filter ensures clean, healthy indoor air quality for you and your family.
Do carbon filters restrict airflow?
Carbon air filters can reduce indoor airflow due to their accumulation of particulate matter over time. The pre-filter may need cleaning three to five times before wearing out, and the impeller blades should also be clean. Activated carbon is a type of carbon that can be granular, powdered, extruded, bead, impregnated, woven, or coated. It can eliminate toxic gases and VOCs, quickly remove chemicals and smoke from the air, and release no harmful pollutants.
Activated Polymer Carbon is a biocompatible activated carbon that has a slick, breathable shell that doesn’t obstruct its pores. It is highly recommended for those with chemical sensitivities and can eliminate household odors from waste, pets, cleaning products, and smoke. The product has a three- to six-month lifespan and is highly recommended for those with multiple chemical sensitivities.
Do carbon filters reduce airflow?
Carbon air filters can reduce indoor airflow due to their accumulation of particulate matter over time. The pre-filter may need cleaning three to five times before wearing out, and the impeller blades should also be clean. Activated carbon is a type of carbon that can be granular, powdered, extruded, bead, impregnated, woven, or coated. It can eliminate toxic gases and VOCs, quickly remove chemicals and smoke from the air, and release no harmful pollutants.
Activated Polymer Carbon is a biocompatible activated carbon that has a slick, breathable shell that doesn’t obstruct its pores. It is highly recommended for those with chemical sensitivities and can eliminate household odors from waste, pets, cleaning products, and smoke. The product has a three- to six-month lifespan and is highly recommended for those with multiple chemical sensitivities.
How does a very restricted air filter affect engine efficiency?
When an air filter fails, two main issues occur: insufficient oxygen gets to the combustion chamber, leading to a rich engine with too much fuel, resulting in lower fuel economy and potentially causing the engine to stop running. Additionally, the filter does not restrict air flow to the combustion chamber as intended, causing the engine to run lean with too much oxygen, leading to hot engine running and potential damage to valves, spark plugs, and other parts.
Ignoring the air filter can lead to more problems if left uncorrected. With the affordable price of OEM and aftermarket air filters and the ease of replacing old ones, there is no reason to ignore the air filter. If your car, pickup, SUV, or van is not running properly and you haven’t serviced the air filter, a quick check could confirm if the filter has gone bad and if a replacement is needed.
Why are 3M filters pink?
The color designation “pink” is attributed to the P100 classification, which guarantees uniformity and straightforward identification. The 3M™ Particulate Filters 2000, 2200, and 7093 Series can be attached to all 3M™ Respirators with bayonet connections.
Does higher MERV restrict air flow?
Before purchasing a high-rated MERV filter, ensure it’s compatible with your HVAC system. MERV-8 filters are popular due to their balance between performance and adaptability, but they can restrict airflow. Filters rated 13 or below don’t strain most HVAC systems, but those rated above 10 may require professional installation. MERV-8 filters are typically 1 inch thick, while MERV-13 filters are 2-5 inches thick.
Maintenance is crucial for higher-rated filters, as they require regular checks to ensure efficient operation. Filters with a rating of 14 or above are typically used in commercial or industrial settings. Installing such filters in residential units may increase maintenance checks to prevent costly damages. For homes with a MERV filter rating between 5 and 10, replace it every two to three months, while for filters rated between 11 and 13, the interval can be extended to three to six months.
📹 Which Car Air Filter is Best? Let’s find out! Fram, K&N, Wix, Purolator, & AC Delco showdown
Best car air filter showdown: Fram Extra Guard, K&N Performance, Purolator, Wix, AC Delco, and EP Auto. Performance testing: …
Thanks for everyone who requested testing air filters and please let me know which brands you want tested in the next round. Also, here’s the list of the ones I tested. Thanks again! Products Tested In This article (in no particular order): EPAuto: amzn.to/3lbyw9E WIX: amzn.to/3aQloBN Fram: amzn.to/3j1stm0 AC Delco: amzn.to/3j2J5tv Purolator: amzn.to/2Qc3pwl K&N: amzn.to/3aJlTh8 K&N Cleaning Kit and Oil: amzn.to/2Qb3Kzk
I was an air filter engineer for many years a long time ago at one of the brands you tested. You do a great job, as always and I applaud your very logical and thoughtful approach. However, I’d like to make a few comments about this report. 1. Flour or powder do not make good test mediums. They tend to agglomerate, and in any case do not compare well with industry standard contaminants. 2. During testing, an even distribution of contamination introduction is critical. Thus, semi-random placement of the test medium can drastically affect the test outcome. A typical test set-up involves an aspirated cloud of contaminant for more consistent and even dispersal to assure a more realistic particle size distribution. 3. Industry standard contaminant particle size is inversely proportional to particle count. In fact, the number of particles increases dramatically (exponentially) as size goes down. 4. Engine wear potential is attributable to particle make-up, i.e. Is it silica or organics, etc., and quantity. Thus, engine wear risk drops dramatically with particle size. Internally moving engine parts, especially rings & valves, are not usually affected by very small particles in small quantities. Five microns is about 1/100000 inches. Concern for wear begins around 10,000 microns or below .005″. 5. Flow is generally concentrated in any filter, despite shape and flow diverting techniques used. Placement of contaminant on the filter media by hand is less realistic. 6. Contamination which agglomerates will increase pressure drop and increase contamination removal efficiency giving erroneous results.
This website is killing me. Like this dude does the most thorough testing on youtube imo well him and gamer nexus if you’re into computers. He has the tools for freaking everything and the few things he doesn’t have he creates himself. Then his scientific method is damn near flawless. I’m like this guy needs a lab coat and some googles at least that’s what I keep expecting.
I formerly worked for an automotive parts manufacturer that was represented in this testing. I find PF’s testing approach to be VERY credible and findings very interesting. One thing to note, any engine air filter is actually MORE effective at filtering particulate with a bit of age/usage as the previously captured foreign material in the filter media increases the filter’s own filtering capacity. That made sense to me during product training years ago, but would have never occurred to me beforehand. There’s definitely an argument for NOT changing this filter prematurely as some of us enthusiasts are prone to do with “over maintaining” our vehicles. Just wanted to add this interesting factoid. Nice job PF, love your content!
As the comments have shown, you’ve helped out so many people out by doing these tests. i hope you’ve never doubted yourself. thank you for saving me a lot of time, worry, frustration and hard earned money. You’re a hero in my book. You and ChrisFix are definitely the most important Auto-Based Youtubers. So many of us rely on your experience. You’re doing an amazing job.
I’m a filtration test engineer for a living and, I have to say, nice job for a DIY style setup. We use pretty stringent guidelines on contamination and particle testing, but your setup was a good idea for a general idea of how the filters perform. The only thing I’d recommend on this one is to think about the fact that a lot of filters are designed for the rated flow-rate of the engine inside the O.E. air box. Air dynamics across a plate mounted filter can do funny things to the measured restriction and cause it to spike or fall compared to when it’s installed in a vehicle. You might be surprised how different the pressure loss can be in those situations. Other than that, nice job.
A few years ago, a friend with a 3/4ton diesel changed over to K&N from OEM. He had had oil analysis done several times prior to changing over, so he had a baseline for comparison. After installing the K&N the next oil analysis flagged “silica contamination” (dirt), and they suggested a leak in the air intake system (check hoses, clamps, etc.). No leaks or loose clamps were found. So he removed the K&N and reinstalled the OEM. The next analysis showed a reduced, but still high, silica contamination, he kept the OEM system in place. With each oil change and each analysis, the silica content went down. It took 4 or 5 oil changes to get back to the baseline he had before he installed the K&N.
I’m going to put in a plug for the K&N filter but not for all applications. Over the years I’ve seen cars come with small perforation in their paper air cleaner elements. I always passed this off to careless cleaning with an air hose. Later I noticed that a many of these cars belonged to drivers who drove 70mph on graveled roads. Most cars have a long snorkel to direct the air into the air cleaner. At high speeds at high air flow this snorkel has a cyclotron effect (actually Bernoulli’s) on any small stones or sand entering the air cleaner & by the time they contact the element they have accelerated to a point that they will go right through it & into the engine. The K&N, even though it’s a less efficient filter, has a filter media made up of cloth fibers & metal mesh which will stop these high speed particles..
I once ran my own K&N versus Donaldson test in real-time. I have a Dixie Chopper XT2800 with a 28 HP Kohler EFI engine. It uses a heavy-duty canister filter. There are actually 2 filters in the canister. An outer filter PN P281575 and an inner safety filter PN P822858. The purpose of the inner filter is to keep any loose dust and debris from getting into the intake manifold when you’re checking and/or changing the main outer filter. I have quite a few hours on this mower, almost 3,000, so I’ve had plenty of chances to change the air filter. Normally with the Donaldson filter, you wouldn’t have to change the inner safety filter because it still looked like it was brand new. I tried the K&N E4961Donaldson replacement filter. I usually check the air filter at my 100-hour oil changes. I opened the canister up and pulled out the K&N filter and it still looked good. Then I looked in at the inner safety filter and it was filthy. That told me everything that I needed to know about the filtering capabilities of K&N filters. I threw both the inner safety filter and the K&N filter into the trash. I’m using nothing but the factory filters from here on out.
Really appreciate the time and effort you put into these articles. Generally speaking find them logically and scientifically sound in replicating world-world conditions. But, have a couple issues with this one. Do you really think: a. Flour is equivalent to dust and airborne particulate matter found in the atmosphere? b. Pouring contaminants directly on the filter material replicates the same condition encountered by dirty air hitting the surface. Especially in the case of the K&N filter–the only one oil-based. Wouldn’t one expect a dry filter to clog less than one using a viscous treatment? Other than that, great job as always!
Another cool project might be to test the integrity of wiper fluids at really cold temperatures. Right now the weather in my area is about -4°F and I have wiper fluid that’s supposedly good to -25 and that is not the case. I think a test like that would be cool with some name brands and some generic ones.
Project Farm’s testing is unlike any website I’ve watched! I’d like to add two things: 1) K&N filters filter particles better when sprayed with the K&N oil, however it is a maintenance item, and I’ve had these run dry and ruin a Mass Air Flow Sensor before. However, they work great in the dust with oil applied. 2) article Idea: Comparing resistance to flow through different spark plug wires, I. E. OEM, Performance wires, versus store bought/common brands.
This is my 1st view of a article from this website, and I’m impressed. I’ve seen TV magazine shows do tests on filters, but nothing this in depth. Thank you for showing us all the specs and how you rated each filter. Very educational and useful data, informed results, without the pressure of a sponsor breathing down your neck like TV shows deal with. Great work! 👍👍
When I bought my 2016 ram, it had a k&n filter installed. I had been running it for a while, and didn’t think much of it. I recently removed the filter to clean it, and discovered the k&n had a manufacturing defect, and the pleats were not doing any filtering along one edge. I replaced it with a Napa gold filter, and I’ll never look back. Not only does the truck perform better, but I picked up 2-3 mpg with the Napa. In my opinion, k&n is not worth the money on a daily driver.
Sir!! You are a godsent. Not only are your vids entertaining but so informative and helpful. Can I suggest that you include atleast 1 or 2 Amazon options in your study as more purchases are trending that direction for ease or purchase and variety. I was looking for filters today on Amazon and an activated charcoal filter caught my eye. Before I clicked I said, “I bet my fav YouTube website did some research on this topic” and sure enough! Thank you so much.
Again you have done a great service to the general public, I dont know why you dont have a TV show on Saturday mornings! Yes I do, You are fair and unbiased! Thank you so much for what you do. I am sure there are times you ask yourself if all the money and time is worth it. All I can say is Absolutely! And we appreciate all your efforts, Thanks gain.
The biggest problem I’ve seen with oiled air filters is oil coating of the mass air flow sensor element on MAF equipped engines. It’s a gradual process (and usually accelerated by someone over oiling the filter after cleaning), but can result in a fine coating of oil and dust on the sensor element. For hot wire sensors this insulates the sensor which can result in an artificially low airflow reading creating a lean and overadvanced condition. Nothing a $10 can of MAF cleaner spray won’t fix, but it pays to be aware of it. Speed density cars (or non-hotwire MAFs) need not worry.
I live in Australia and have travelled the “outback” extensively. The finest dust we have is as fine as talcum powder. K&N filters are useless out here. Either an OEM or a WIX air filter have been the most efficient of paper filters on all of my vehicles, that l have been using since 1972. “Donaldson” brand of air filters are, in my opinion, the “Rolls Royce” of air filters, hands down.
I was part of a test for a F1 manufacturer in the 80’s and they looked at intake air filtration. With paper filters it is pretty much dictated by surface area as your test shows. The K & N is different – we saw less flow and less filtration on a simple flow bench like you put together but better power on the dyno. We scratched our collective heads about what was happening until it occurred to someone that pulsing flow was critical to making the K&N work and then built a test rig to simulate that. What seems to be happening is that the cotton fibres form a dynamic filter where the fibres are working like an interlocked gateway.
I’m really curious about the box being inverted and dropping the particles onto the filter, since most air filters by design go from a narrow throat to a wide area to allow large particles to drop out due to air velocity decrease, before needing to be sucked upward, through the filter. Also I’m curious about the actual air speed into your engine being as high as your setup. If you compare your setup to your truck’s intake velocity, i appreciate knowing that. Would you be willing to do an added test with the real air box, intake tube, orientated the way it is in the vehicle and a set amount of flower puffed into a tube connected to the narrow throat of the air box at the actual velocity of the air intake tested at the high RPM range of your truck? Curious how differently everything will change, especially static pressure differences between the filters. Just like sucking quickly between a narrow and wide straw, there is major static difference; however, suck slowly on both and it narrows. Love your articles and suggest them to everyone i know! Hope you are doing well!
I was wondering if youd be interested on trying out different: fuel injector cleaner – fuel additives Love the content and probably the only website I watch the entire commercials for haha please keep up the great content sir, I truly appriciate your hard work and non bias opinion I learn alot about products and brands I wouldnt have given a chance
This analysis was extremely well-thought and helpful! Would you consider doing a similar analysis of engine oil filters? There are many articles where various oil filters are dissected, but none that I could find that analyze the filters’ ability to remove contaminates while maintaining a decent flowrate. An oil filter’s internal construction may not indicate its effectiveness in removing contaminates. Could you put that type of article on your short list? Thanks again!
So just speaking as a GM diesel tech here, from what I’ve seen in my day-to-day line of work, an OEM filter is the beat for your vehicle. However, regular maintenance is far more important than any brand on the box. One issue we see with aftermarket air filters is that every filter by Wix, or Fram, or Oriley’s are all cut from the same filter media; I.E. a Duramax filter is cut from a roll of filter media that a Mercedes filter is cut from, and the same roll as a Honda filter and the same roll as a side-by-side filter and so that can effect MAF readings. Another issue we see is with the K&N filter, since they’re oiled, someone that doesn’t clean and oil their filter properly (too much oil, doesn’t wait a day for oil to soak/dry before installing) can cause lots of issue too; oil on the MAF sensor can change readings and performance issues. So too make a long story short, the beat thing to do is inspect/replace air filters regularly and use OEM filters
I’ve known about the great filtering performances of Wix and Purolator OIL filters, so I wasn’t surprised by their superior performance in the AIR filtering test. I was surprised at how poorly the K&N did in the particle filtering compared to the paper filter media types. I should have known that less restriction to airflow would would translate to larger holes for contaminates to pass through, and the test proved that to be true. Next trip to dusty West Texas, the K&N stays at home and the WIX goes for the cruise. Thanks for a great through (as usual) comparison test!
This makes me wonder how important clean air really is to an engine. My last car, which my oldest daughter still drives, has always had a K&N filter in it. It’s now at 430k miles and has never had an engine problem. An ICE does consume/burn whatever goes into it. Does a little dust really matter? Is it going to survive combustion to cause problems over time? Doesn’t sound like it. I wouldn’t run no filter; but the least restrictive one available sounds like a safe bet.
Hi Project Farm, former Navy here who has now retired on his own “Project Farm” (Northeast USA), could you tell us and advise us of some of the testing tools that you are using for this test or on your car battery test – I am not asking you to do free product placement advertisement but you put your instruments to good use and it would be good for me to locate where is most of the dust coming/leaking from my silos (forage), or harvester, or in the tractor cab (I have asthmatic relatives). A article on useful testing equipment would also be appreciated, especially for tools that are not that common but that you do put to good use. Thank you again, Ciao, L (Veteran… who finds your articles very “therapeutic”).
Love your articles. Just wanted to add my 2 cents. I sell autoparts to to repair shops. For a customers car they buy the cheap house brand stuff. For their own cars they always want Wix, Castrol, Moog, Gates etc. Name brands they know and trust. These the professionals. But I keep an open mind when it comes to this website. If anyone could prove them wrong it’s you.
I have a great idea for this website. It’s driving me nuts because I’m only seeing these filters put into C8 Corvettes. It’s the TKO Nano “Attack blue” filter. No oil required and it is reusable. I would love to see a stand off once and for all K&N vs Attack Blue nanotechnology filter. ( one good thing to keep in mind is the sq inches of the filter) but you understand all this! Thank you for your work!
Interesting conclusion. I had EP Auto and Purolator. Clearly the Purolator had an edge over the rest in filtering ability but stayed relatively low on static pressure as opposed to the wix which was the highest in the end. EP Auto did pretty well on all the tests even though it was somewhere in the middle for filtering ability, the difference between the top half vs the bottom half is so huge that I can’t say how meaningful the difference between EP and the top 2 really is. Given that, the fact that EP’s 0-60 was better than average (or was it average?) and the fact that it’s half the price or less than the top two performers, it’s clearly a decision between EP and Purolator. That said, if you keep a car from new til it dies of old age, you’ll probably change air filters maybe 20~25 times? So spending around $200 more over the life of the car may be worth the difference in performance. Perhaps it may be the difference in whether you change it 20 times or 25 times, who knows. Anyways another great article!
My Dodge/Cummins Ram 2500 had a K&N filter when I bought it (used, of course). When I went to clean it, I checked the intake pipe and found it coated with oil carrying very fine grit. I threw the K&N away, and installed a Wix (NAPA Gold) paper filter. I notice no reduction in performance, and the gritty slime did not come back. I also use a NAPA Gold oil filter on that engine.
New subscriber here.. after perusal your furnace article I was curious about other filter articles you had made. I work on the road (45k to 60k km/year) in the particle/contamination control industry. You make a good controlled test, but you should make an effort to build a test rig that simulates the standards that the filter media is actually tested against to meet said standards in the industry. Filter media efficiency is not the same as filter integrity. You test the the filters as a sieve when you dump the particles by hand over the top of it, of all the articles and rigs I’ve seen you make this is the only time I see you introducing random factors and tester bias. I’m not being a dick, just providing constructive feedback based off my area of expertise ; I love your articles xD Feel free to contact me if you want advice about filter/particle tests, I would love to help you out. edit : I really enjoyed the part of the engine 0-60 performance… as I am not a combustion engine expert, I am astonished of the measurable difference between filters.. as to how they affect the motor however, hmmmmmmm.
Would love to see a test on Motorcraft air filters specifically the FA-1782 for my 6.8L V10. I change them pretty often because the V10 uses A LOT OF AIR. I had a K&N filter in it but heard bad things about the oil in the filter contaminating the MAP sensor. I opted for more protection than the K&N filter and the Motorcraft air filter was an obvious choice.
Very thankful for your website. I have gleaned so much from your comparison tests. One thing that I picked up on was that, as you mentioned, the K&N is rated as a lifetime filter that requires cleaning every 50K miles (depending on conditions) whereas with all the others you would need to purchase another filter every 12K miles. So obviously, in terms of price, the K&N would be the clear winner.
This article makes me curious, I wonder on the particle test were the particles detected with the K&N Filter oil particles because of how the filter is designed to work. Awesome results all the way around regardless though! P.S Maybe do these tests on an Oil Bath air filter, either for fun or as an experiment. I know its not realistic but I think it could be fun to see the results!
Excellent article, many K&N advocates boast about the increase in hp which is very small but never mention that it does a pretty bad job at what a filter is supposed to do, block contaminants. I mean if you want super good hp, why even use a filter right? Just because a filter seems to give you better airflow, that does not necessarily mean that it is acting as a good filter. Overall, the difference in hp is so small that any increase in performance would be unoticeable while the integrity of the engine itself is compromised. My experience with K&N cleanable filters is that no matter how well you clean them, they are still going to retain some level of dirt and grime. This will eventually built up over time despite periodic cleaning and will progressively cause deteriorating performance, even if it looks relatively fine. Furthermore, I’m not too keen on having an oiled filter within a airbox meant for air, it’s simply counterintuitive to basic mechanics. Overall stick with oem paper filters, they are the simplest and safest option.
There are very good reasons why a filter like K&N did little for the static test. The reason it’s oily is that it’s using particle momentum to trap the particles. Any spongy filter like that tends to have much larger openings than a paper filter, so free-floating dust can find ways through, as we saw here. In operation, though, while the pathways are relatively large, there’s no straight-line path through the filter material. Air molecules have little trouble navigating the twists and turns, but dust particles have too much momentum and end up running into strands of cotton and, because they’re oily, sticking to them. I don’t think having a bunch of dust poured onto an open air filter is a very realistic scenario, nor is that short burst. The only of these test results I’d take very seriously is the steady-flow test, and there, the K&N did very well, as I would expect.
This was a pleasant and informative article to watch, appreciate it Project Farm! I would love to see a Denso air filter taken through the rounds as they like to sell big on their “triple layer filter design” Unfortunately I don’t think they would sell Denso for that Vehicle, but I’m sure you would find a suitable solution. My one possible slight gripe though, is that it appears that you didn’t do multiple tests for the Filter Particle Test. As it seems to me like there was too many possible variables at play to only do one particle test. However I wouldn’t be surprised if you may have a reason unbeknownst to me… 😉 Cheers! Keep up the wonderful work!
Being a k&n guy, there is nothing that produces more airflow. but I’ve never driven through a field of flour. That being said revving my chevy truck to 6000rpm probably damage’s it more than the particles introduced from the larger openings in my k&n. love the articles and my local napa will be happy that they sell the best filter.
Some good testing for sure! My.opinion is starting with a contaminated, upside down filter, is a bit of a misnomer. These filters are not installed that way and arent usually contaminated with dust and dirt like the test. The K&N is designed to create static when the filter media vibrates which causes the particles to be attracted to them and allowing the oil to capture the particles which I believe is why it performed well during the continuous flow testing as that is what it is designed for.
I remember seeing someone that had put a secondary filter medium behind his vehicles air filter and did a comparison where you could see the dirt that passed through the air filters he tested and did a real world test. I believe he also weighed the secondary medium before and after also. The K & N was the worst. He had to drive on dusty roads and would leave the air filters on for the same time.
Love the website and am always looking to see if you have covered whatever I am looking to compare before I go anywhere else! I am sure you have heard this one but having a comparison on oil filters would be awesome. Others have done it but a Project Farm would do it best! Thanks for making the content.
Thanks for sharing this test. I’ve always been a K&N fan for the performance results but never realized how bad it was at filtering. I don’t mind taking on more small particles since it’s just going to shorten oil life (except the ridiculous amount by K&N). I do mind taking on more large particles that can actually damage the engine. I would love to see how the CarQuest Premium holds up. It seems like a great middle between filtering and performance. Goodbye K&N air filter for me…their oil filter can stay esp now that the oil will be cleaner.
Great job, I got to say I’m shocked by the K&N but Fram never fails to impress me on what filter to never buy… Fram, ya guys are still number one for putting out garbage…. I wonder if Fram filters would be better used on my cat’s litter box.. You think that would be a good test??LOL But serious, thank you much for the testing, it was first class…
I’m curious on how well Fram’s new Ultra Air filters stack up to all these filters. It would be a good test to see if anything improved over the extra guard series. I know lots of people have been saying great things about Fram’s Ultra Synthetic oil filter line. Overall I appreciate the length of testing you do in all of your websites, and various products you cover 🙂
Another great article. Thank you. In 2012 I took my 2011 F150 w EcoBoost to Sarasota, FL from Decatur, TX pulling a 22 foot fiberglass boat on a tandem axle trailer. It was a great test of things to improve fuel mileage. I tried octane booster, high-octane pump gas, and even changed to a K&N air filter on the trip. The only difference in fuel mileage came from the high-octane pump gas and then only offered a $0.01/mile savings with the higher cost of the Premium fuel. The K&N made no difference in felt power or fuel mileage the higher flow rates they claim always seemed to indicate inferior filtration which I think you showed here. What always irked me about the K&N chatter was that they reportedly filter better when they are dirty…no kidding…as it gets clogged up, it filters better. I already had bought my last K&N after that trip, this article just underscored that.
So a few other suggestions might be testing alternators from places like Napa, AutoZone, O’Reilly, etc. Also perhaps screwdrivers…. It seems like so many are so cheaply built anymore. Also, perhaps sockets?….. So many seem to strip out if they’re cheap. You do an absolutely amazing job and have so much credibility. I love sharing your website with all of my friends and family. Please keep up the good work
K&N is the best, watch David Vizard’s article on it, in his flow testing, it showed to not be any better than a paper filter, but on the engine it performed better, called K&N and they had observed the same thing but didn’t know why, turns out, the engines vibrations create motion between the layers of mesh, allowing greater airflow but still restricting particles. at a stand still imagine the waffle patterns interlacing are closed, but during high vibration the patterns shift diametrically allowing airflow but deterring particles
Thanks for confirming my experience! I drove about a 1000 mile (three times) move towing a fully loaded cargo trailer. I just changed the oil (Lucas synthetic) before the move and installed a K&N filter. Well, I recently changed the oil because of a pan leak and I’ve never seen such black oil after about 5k miles! I’m going back to the OEM filter which I saved and was very clean.
I wished I would have watched this before buying the K&N ($56) filter from Amazon yesterday that was delivered and installed today. Well, leaves me with another question. How did YouTube all of a sudden put this on my Home Screen? I didn’t search anything about filters! We are being watched and listened too…
I run a school bus shop and we use air flow meters to gauge our filters. The filters do their best when they are about 40% clogged. I changed one on a maxxforce DT466 last year that had over 150k miles and was still good. It was clogged with dust and dirt but the inside was clean. It had been in the bus since 2011. The flow meter said it was at 30% life left. But at 100 plus per filter you would expect it to last. These are large can style filters. I run a k&n in my truck and I notice more dust on the clean side of the filter box then when I ran regular paper.
I would argue that the results for the K&N filter by using so much flour would be invalid. K&N themselves will tell you that it’s the oil itself that is the filter material however if that oil is absorbed by the flour and removed from the filter then it can no longer do it’s job. i’d be interested in seeing the performance of a K&N filter when driven through a sandy desert as that is very harsh on air filters.
Ive run the same K&N filter on my 2001 Tacoma for the past 22 years. Wash, oil and use. Year after year. I remember the testing on these filters back in the day and they said that what was special about the filter was it still flowed more air after it got dirty and well used than the competition did when new. I dont remember anyone saying it made your intake air sterile.
So I researched into air filtration technologies and published research articles on airborne particle sizes and concentrations, particle size affect on engine wear, and factors in predicting engine wear based on air contaminates. I take back what I said about the filter being saturated with flour and I believe the filter was properly oiled. Turns out it’s way more complicated than it seems and even academic researchers are struggling to reach a consensus on many of the basic points. K&N claims between a 96-99% cumulative filtration in ISO 5011 testing (knfilters.com/efficiency_testing.htm). Dry filters on the other hand should see nearly 100% filtration down to their pore size (which we saw in you testing). But there’s a catch, once you go below the pore size nearly all of the particulate matter should pass straight through the dry filter (though they can actually act like finer filters as they clog at the significant expense of airflow), where as the oiled filter should continue to filter out 96-99% of the particulates no matter the size. Typical flower is 89-98% 10-41μm and 41-300μm particulates, and 2-11% 10μm or smaller (sciencedirect.com/science/article/abs/pii/S0733521084710587). In conclusion, it appears that neither dry filters or oiled filters alone can fully protect an engine from wear but dry filter are by far more effective at stopping the most dangerous debris. I wouldn’t be surprised if we eventually saw a high performance car intake system that uses both technologies with the oiled filter being a maintenance free item and large replaceable dry filters being the primary flirtation.
I learned the hard way about K&N filters when, during regular oil analysis of my ’94 Taurus SHO (Big shout out to Blackstone Laboratories – ProjectFarm might not be able to show their name in his reports but I can!) a huge spike in Silicon was noted… along with a rise in lead, tin, copper, aluminum, iron… Blackstone straight up asked, “Are you running a K&N? We’ve noticed that they let a lot more grit and sand through.” Sure enough… I took it out, put a regular paper filter back in and on the next report Silicon, et. al. levels went right back to normal. It’s wonderful to see validation of this from a trusted source, even years later! Thank you!
Time for a fresh Filter… Had bought/used a K&N filter some years ago. Never got around to “recharging” it and its been sitting on the shelf since. Don’t think I’ll be putting it back into service any time soon. Just changed the oil yesterday at 180,002 miles… As it is worn/burning oil don’t think I’d like tempting fate with more Particulates…
HA!! I’ve always thought this about K&N. It’s simple, you can’t have it both ways. Filtering is resistance plain and simple. People have told me in performance cars they use K&N at the track because of the better air flow and that it makes all the difference. I say for 13 seconds take the filter out for crying out loud then put a real (Wix) filter in lol. These articles are the best. Thanks for making them!
I hope you consider it. I have two Diesel Trucks, LML Duramax 6.6 and a LZO 3.0 and aparently the stock filters may be inadequate, The 6.6 doesnt have any lift pump it works on vacum and the 3.0 has the same filter GM put in the Chevy Cruz and its problematic. I’d guess I’m not the only one with the delima. There are all sorts of after market solutions that “Aint Cheap” If im going to invest in a expensive fuel system It would Be AWESOME to have your input and data. Thank you for the response and for all the Great Content!