K&N Auto air filters, do they work?
JohnHens
| Posted in Tools for Home Building on
I was told about K&N air filters, they will improve performence and mpg’s.
Is it true and does anyone have experience with them?
Thanks
John
Replies
While they will be less restrictive than paper, they also pass more particulates than paper. Good for racers who will rebuild engines, bad for long life applications.
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
There seem to be 2 camps on K&N. The "great marketing hype" camp and the "the sun rises and sets on them" camp. I guess I fall into some other camp, though, now that I think about it. It's doubtful any realized HP gain is gonna be noticeble on typical engines in typical rides...hair splitting, methinks.
I have one in my truck that's at least ten years old. Built engine, open filter, cleaned and reoiled a few times, I'm married to this truck so it makes some sense dollar-wise to have one filter forever, plus it looks cool :)
Motorcycle came with one and I hardly ride it so it's a forever filter too, I guess.
Other rigs get mid line paper filters.
Paul what's the skinny on particlulates you mention? I'm guessing K&N would disagree. Oiled gause or foam filters are usually considered dang good, but I'm no fluid dynamics expert. Tell me more.
Everything will be okay in the end. If it's not okay, it's not the end.
Edited 8/19/2009 7:05 pm ET by PeterJ
I have them in my car - haven't dynoed but there appear to be HP gains - supposed to be 10-15 HP (maybe) ;o).
Jeff
My wife has one in her Tiberon and noticed th hp gain right away. I have one in my jeep and didn't really notice an hp gain but I did notice that I get more MPG.
"All he wanted was some beer. And they shot him in the face." Wilma to Two Puff Johnny on a train bound for CrazyLegs Fest.
K&N on my truck. cummins 3.9 diesel stepvan. paper filters to expensive. K&N lifetime filter, did not notice any performance changes.
wookie
Bad idea. Diesel engines are unthrottled, always pulling way more air than a gasoline engine. Turbocharging pulls even more air.
If you do not keep up on the filter maintenance, you will shorten the engine life... and you can see through the K&N media, so what does that tell you?
No way I would run a K&N on an expensive diesel engine. It may take 200 or 300k miles for the damage to show up, but once it does, the engine is done.
Plenty of K&N discussions on http://www.tdiclub.com
A K&N filter might be good for an engine that racks up miles 1320 feet at a time and gets rebuilt when it is grenaded, but there is no way I would ever put one on a diesel... no matter what their marketing says.
I've had one bad experience and one good one.
I bought one once for my Ford Powerstroke, but it didn't fit snuggly and leaked unfiltered air, in spite of using the special grease that they sell to help with sealing. Total waste of money.
I've just bought one for my lawn tractor because we have a lot of summertime dust and I am tired of forking out $25 every six months for a OEM filter. So far I'm happy with this one.
As for improving performance and MPG, I don't buy it. The principle reason for buying K&N filters is to avoid buying OEM filters for the lifetime of the motor.
Scott.
Edited 8/19/2009 7:41 pm by Scott
i always thought you could buy a lot of normal filters for what a K&N costs.
>>>i always thought you could buy a lot of normal filters for what a K&N costs.I guess it depends on what you call "normal" and of course it depends on how long you plan to keep the vehicle.In the case of my lawn tractor, it was a no brainer. The OEM filters are ridiculously expensive. It's an 18 HP Kawasaki engine (great engine!) but the air filters are $25 each. I go through at least one, sometimes two per year. The K&N filter was $54, so after two years I'll be filtering for free. I plan to have this tractor for many more years (hopefully).Scott.
can't you just blow 'em out with an air compressor?
>>>can't you just blow 'em out with an air compressor?Tried that. It helps for the first couple of times, but eventually the paper gets so loaded up that you can't get it clean. We've got lots of fine clay dust here, so that doesn't help any.Scott.
>>can't you just blow 'em out with an air compressor?<<Talking to a Donaldson engineer a few years ago, that is a very bad thing to do, although it's a common practice. The paper filter medium is tightly controlled when it is manufactured for it's porosity size. When a blowgun is used on the paper, the pores open up and with the filter placed back into service more dirt is passed through compared to a new filter.Also found out that when a filter is new it flows the most air but lets in the most dirt. As the filter starts to fill up with particles the porosity is smaller and filters finer particles. When filters are changed too early on a routine basis, the motor experiences a dirtier life then one where the owner has been lax in changing them on time.The motor may be air starved, but with the new electronic controlled motors, the fuel injection will be compensated down for proper emissions. Less full throttle power, but fine in normal pedestrian operation. Oh mama got it wrong.
good points.
>>>When filters are changed too early on a routine basis, the motor experiences a dirtier life then one where the owner has been lax in changing them on time.Well said. It's ironic that the best filtration occurs with an element that is laden with dirt. Of course, this results in increased restriction. Like most things in life, it's a matter of compromise.Scott.
I noticed that with my dust collecter bag too, a little cake left in the upper bag lets less through into the room.Spheramid Enterprises Architectural Woodworks
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I have drop in K & N's in both vehicles. I feel that they get worse MPG. I noticed that the boxes they come in, in the store, do not say anything about better MPG anymore??? (they used to)I figure if more air comes in, the computer increases injector pulse width (spray time) to keep the air/fuel ratio as close to 14.7:1 as possible (normally aspirated engines). Thus more power/less MPG. I will be changing back to paper soon in at least 1 vehicle. If I don't post, remind me and I'll let you guys know how it turns out. Almost every dyno I've seen shows a low end loss and a high end gain (rpm) for stock N/A motors. That's great if you're winding out your engine all the time, but for the daily driver remember 1 thing.
Torque gets you going
Horsepower keeps you going
My stock Chevy engine air filter is rated for 50,000 miles, so I can't see using a "recycled" filter. With modern fuel controled engines no extra power will be seen. Just more noise from most of them.
The reason they are supposed to increase HP and MPG is they allow more into the engine
Most stock exhaust systems are restrictive by being to small
So if the exhaust is to small it does not matter how much air you get in because it cant pass thru
"if the exhaust is to small it does not matter how much air you get in because it cant pass thru."
If you get more air IN the cylinders you would have more pressure pushing its way OUT of the cylinders.
Nothing you put in a banana split is as fattening as a spoon.
I dont believe it works that way in the average car/truckmaybe using a blower or a turbo but ya still have to get the exhaust out
Most stock exhausts aren't nearly as restrictive as people think they are...................quiet yes, but not nearly as restrictive.
Some of that comes from the fact that a free flowing exhaust will make a little more power but also move it further up the RPM range...........fooling people into believeing that they are getting more.
Most people don't know this............but the straight pipes some Harley riders so love? Usually create between 4 -8 HP LOSS on a stock V-Twin compared to a stock exhaust.
Intake on the other hand.......is often already restricted due to noise limitations. The engine is just an air pump..........and the more air in? The more power out.
Pop the filter out of your car or truck and go for as ride around the block.
I have to agree with you to a pointThe exhaust in the last few years have got betterBut still very restrictiveAs for your Harley exhaust I agree 100% - Short straight pipes eliminate all back pressure those engines were designed to haveNow ya wanna get really crazy with exhaust - start dealing with a 2-stroke
Now ya wanna get really crazy with exhaust - start dealing with a 2-stroke
FMF Pipes if it's new
DG if it's vintage..............but damn the DG stuff for Vintage bikes is pricey.
Early 70's yamaha enduro's 175, 250, 360Only hooker header for meLoved the sound but I think it was the name and the heart on the heat sheild that did it ( also great stickers)Don't know if the performance was all that great compared to other non stock pipes but then again our porting was very wild and used 4 to 6 mm larger carbsThose were fun times
doesn't quite work that way. That is why tuned headers can make a big performance difference.In order to use engine power to pull air in and push it out, you lose horsepower. Balancing things means more power delivered to the wheels.
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I don't buy that at all. If you can get more air in you're gonna push more exhaust out because there's more pressure in the cylinder. If you can get exhaust out more efficiently more air will be drawn in because the cylinder will have less air in it before the intake stroke. There are limits, of course. You can only improve the exhaust just so muich before you really need to address the intake side. But any improvement on either side should make SOME difference.
How can a slim chance and a fat chance be the same, while a wise man and a wise guy are opposites?
"There are limits, of course. You can only improve the exhaust just so muich before you really need to address the intake side. But any improvement on either side should make SOME difference."Yes, that's why I used the word balance.Fact of physics though, to FORCE more air out the pipes- you have to get the power to do that forcing from someplace. Since the engine is the power supply, you are taking it from there. How much before it is noticeable is the only question
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if you increas the inlet sizes considerably..
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The husband of my wife's brother's wife bought one for his pickup. Didn't see any difference.
Back in the days of the carburetor, a K&N would make a difference in mileage. With todays computer controlled fuel injection, the fuel/air ratio is controlled by the computer. Restricted intake makes no difference.
I keeep everything stock. I used to mess around with cars and trucks but it never really paid off.
Most of the time the aftermarket product didn't do anything and cost me a lot of time and money.
Messing with cars and trucks is a money pit.
I do regular maintenance. Normal, regular, boring, maintenance.
Will Rogers
In a former time I spent thousands of hours on a flow bench... the whole idea of an engine as an air pump... getting air in and out in a manor that is the least restrictive yet holds the fuel charge in the air at the proper ratio to have the most effective burn rate... and then expels that same charge in the most effective way...
lots at work here and guys have spent lifetimes understanding it...
filter.... if you can increase the surface area... ie the reason filters have pleats ... the more surface area the better... K&N uses a cloth media soaked in oil... by the nature of cloth it'll have more surface area than smooth paper... thus should be more free flowing...
try to breath through a cocktail straw... yeah you can do it takes a ton of effort... now breath through a regular straw... not a ton of effort but still restrictive... now try paper towel tube... non restrictive.... now 1ft of 4" pvc... still non restrictive...
IE... you reach a point where once it's not the the thing that limiting your breathing... IS your airfilter the most restrictive part of your intake system?
if it's not you will see zero return on a filter change...
for the most part in my opinion and the dyno charts i've seen a switch to a cloth oil soaked filter resulted in a net zero gain... at times even a loss in HP...
just my opinion.... but if you are looking to make more power... this ain't where to look...
K & N does sell whole engineered air intake systems that do help... but it's because they are larger less restrictive tubes and hoses than stock... it ain't the filter...
p
just my opinion.... but if you are looking to make more power... this ain't where to look...
K & N does sell whole engineered air intake systems that do help... but it's because they are larger less restrictive tubes and hoses than stock... it ain't the filter
Also because if you look, the kits actually eliminate the bulk of the airbox. The boxes themselves are very restrictive due to EPA noise levels.
On a dirt bike one of the cheapest, most effective modifications is to open up the airbox itself. That getts more air in there to be drawn thru the filter.
Improved performance?
Maybe, back in the day of carburetors and skinny round OEM filters. Tall filters helped then, allowing the air to take a better path and straighten out a bit more.
Modern OE flat panel filters have a lot of media in there. More media = less restriction.
The dirt that the K&N traps absorbs the oil film needed to trap more dirt.
If the filter has too much oil, that is pulled off the filter and onto the electronic sensors that determine engine airflow. Hot wire airflow sensors do not do well with an oily coating.
I wouldn't use a K&N on a daily driver.
Right now, the best oil and air filters on the market are AMSOIL Ea synthetics. The synthetic (vs cellulose) media has consistent openings.
I'll throw in my $0.02. My background is automotive R&D for the last 30 years. I'm one of those diesel nuts and a few years back managed an oil research project over at a Ford Powerstroke site where I took all of the oil analysis data that owners were getting and put them into a huge spreadsheet to track oil life (with and without bypass filtration) and other aspects. One of course was the different air filters that were being used, i.e. stock, K&N, Tymar, Donaldson, etc.
As another has mentioned, the issue with the oiled filters is contamination of the MAF sensor, which most often cannot be cleaned successfully. the cost of replacing that sensor far outweighs any cost benefit of using a washable filter. And many auto manufacturers will deny any MAF warranty if the is an oiled filter present in the vehicle.
And if you are too light on the oil, then the engine gets "dusted", something that diesel motors are very prone to do to the fact they pump through full amounts of air and are not "throttled".
A K&N can be very effective in keeping out dust, but the problem is that the oil has to be applied perfectly. And most people do not do that.
A K&N can be very effective in keeping out dust, but the problem is that the oil has to be applied perfectly. And most people do not do that.
And the CORRECT oil as well.
I'm surprised at how many guys think their jetting is all screwed up on their dirt bike.......only to find out the filter is SOAKED in 10-W30.
I learned my lesson the hard way.. On my race car I used a K&N filter, I bought the specil oil for it and followed the instructions exactly..
The engine barely ran and not at all over 3500 rpm.. I checked and double checked every thing jetting, ignition, timing, cam timing, did a leak down test, etc..
I entered the final race of the weekend with the lousy running engine so pizzed that I simply wanted it to blow up and put me out of my misery.
Lap after lap I sputtered around staying out of the way of the faster cars lapping me,, cars that I would normally be dicing with. Just as I entered the main straight it cleared up and ran perfectly! Yahoo!
The joy, the bliss, I ran the cool off lap like it was the first lap of the race. There was a Lotus Mk 6 who'd been pulled off at Canada corner for some reason and he pulled out in front of me.. I was doing 100 he was doing maybe 20. Bang I hit him.. my one and only accident in a lifetime of racing.. (trivial damage to my Jagaur but knocked the left front off the Lotus)
Any way I found that taking on and off the air filter I'd forgotten to safety wire it and engine vibration had caused the air filter to fall off on the last lap.
The problem was that the instructions I had were for a differant filter and I'd been using too much oil.. Once my engine got some air it became the wonderfull thing it always was (and still is) The amount of excess oil was trivial. Any filter that sensitive isn't something I want to count on.
My pick up truck with 300,000 miles on the Chevy 350 has had nothing but paper air filters, usually genaric. In a 4wheel drive pickup I still get 17 MPG city and 19 highway. I haven't spent a dime on the engine and it still doesn't use a drop of oil between changes..
I had a 96 dodge ram and towed a heavy trailer. when I put the K&N filter on, along with the improved exhaust, there was definately an improvement in the power, mostly going up steep hills. As a consequense, the gas mileage went down, because I could tow faster.
Other than that, I don't see where the costs on the filter and exhaust were worth the additional costs.
The real negative is that the intake parts that were needed to use a K&N on tghe truck were poorly design. Easy for them to leak and they eventually broke.
Read this.
http://www.bobistheoilguy.com/index.php?option=com_content&view=article&id=58Itemid=66
I bought one just for the cool sticker that goes next to my STP sticker.
There babe magnets!!!!
Back when everything on my truck was modified, I had a K&N for about 3 months. I got the first Blackstone report back and threw the filter away. It let entirely too much garbage pass through it and the oil analysis proved it. I ended up with a Donaldson that, coupled with Chevron Delo, showed almost no wear occurring. The HP increase is silly. In some scenarios, on some vehicles, with a certain driving style, you *might* have some horsepower gain. Will it be big enough to measure?
Filters dont make horsepower. Injectors will. Programming will. Paper, not so much.
Real trucks dont have sparkplugs
Thanks to all who shared their experiences, I guess I will stay with Fram!!!
I thought it was too good to be true, glad I checked !!!