k & n filters



  • cdeancdean Member Posts: 1,110
    you are right about the oil giving horsepower. if you look on some of the oils you buy for gas motors, some of them a star that says gasoline saving on them. little things like that make a difference when it comes to horsepower and mileage, thats the point i've been trying to get over with the airflow thing. stuff i never thought would make a hill of beans difference, actually make big differences.

    on the oil thing, for example, did you know NASCARs have special plates shielding as much of the crank as possible from the top to prevent any oil at all from dripping onto crank and robbing horsepower during operation. sounds ridiculous, i know, but its not.
  • sato8sato8 Member Posts: 7
    it's called a windage tray, it goes between the crank and the oilpan and stops the oil from splashing onthe crank thus robbing the engine of horsepower, I have one in my 1970 dodge challenger 440 magnum ,it was a factory installed item, the motor came from a 74, highway patrol interceptor. I originally did not know what it was for until I called direct connection(mopar perfomance). as for the kn filter, I believe it helps but not as much as kn claims, but is part of an overall performance upgrade package, I've already order one for my 98 ram p/u with 360 engine. since I used kn filters in all my veh's , most noticeable in my 92 harley 1340 motor. Just another thought I am satisfied with my rams mpg and performance being american the quest for better mpg and perfomance never ends, anyone knows whether the after market hot ignitions help such as crane, accel,nology,jacobs, thanks to all my 2 cents..
  • lwflwf Member Posts: 223
    Cobra98 mentioned something pretty important; that is, having a dyno to be able to measure any HP gain one might get. I surely don't have one, nor do I have access to one, and I doubt if many others are in a better situation. And without one, I don't know how any of us can quantify any change in HP as a result of modifications such as the ones that have been discussed.


    In regard to your comment about the "force it takes for each piston to move", that's what Dave is referring to when talked about the pressure delivered to the combustion chambers. But I think I hear everyone saying it's time to pack it in for this topic, and I agree. It's been fun and I think I learned a lot, but there's still a lot I feel uncomfortable about.
  • cdeancdean Member Posts: 1,110
    i think we are at a standstill about what it takes to pull air thru a paper element and thru restrictive plumbing. i think it takes a lot more power than you do. there it is.


  • richflynnrichflynn Member Posts: 147
    I think that I may have the ABSOLUTE and definitive answer on the K & N air filters. I was at the Fontana track for the BGN race and picked up a K & N brochure from their booth. This is based upon the K & N 'Flow Control Air Cleaner'.

    In their brochure there is a graph that is a set of horsepower curves; one with and one without. Remember, these are K & N numbers. I'm not sure where they were derived, but I would guess from a dyno comparison.

    The graph is based upon a a'355 Chevy, 10.1 Compression Ratio [I think that they really mean 10:1 CR.] and a 2 barrel carb.' The graph is annotated "Base line has no air cleaner." The graph has HP on the left and RPM on the bottom. The graph starts at 250 HP and 3800 RPM.

    The HP curves start in the 260 range at 3800 RPM. There is a difference between the two curves, two, maybe three, perhaps even 4 HP at times from 3800 to 5400 RPM. Then the stock, no air cleaner curve becomes uneven with a few peaks and valleys. The K & N curve is smoother up to about 6300 RPM and then it follows the stock curve.

    The literature suggests a 20 HP gain. That may be a bit of marketing license, as I can only see (At identical RPMs.) a 12, maybe 14 HP gain with the K & N filter. The 20 HP gain may also be over the stock filter.

    There are four points here.
    1 - I've driven a vehicle with and without an air filter. I did not notice any difference.
    2 - The vehicle sounded much better without the air filter.
    3 - The K & N literature shows the horse power gain to really start at 5400 RPM. Below 5400 RPM, the gain is difficult to see on the graph.
    4 - The K & N filter gains horse power over a NO FILTER configuration. (However see point #1.)

    My conclusion is that the K & N filter does improve horse power at high air flows and high RPM. Unfortunately, not many of us drive our vehicles under these conditions.

  • jim2jim2 Member Posts: 43
    I see a great deal of discussion about intake but little concern for exhaust.

    I have been using K&N and other high flow air filters on off road four stroke motorcycles for years but only with jetting and exhaust changes as well. On a four stroke motorcycle engine, just changing the filter to flow more air, which they do, is only part of what needs to be done. Rejetting the carb to allow for more air to fuel mixture and improving the flow at the exhaust pipe are all critical to improving the performance.

    I have personally seen dramatic improvements across the RPM range on these motorcycles when all three things are done.

    I have never tried this in a fuel injected auto engine but would assume the electronics would adjust the air to fuel mixture if more air flow was achieved with a K&N but I'm not sure there would be much benefit without also modifying the exhaust to also make it less restrictive.

    When doing these modifications to motorcycles, performance is improved but pollution is increased. I would assume this would also be the case in an auto engine and after making all three modifications, your engine might not pass its next smog inspection. However, adding flowmasters behind the catalitic may not create a pollution problem.

    I believe changing the filter would help some but adding flowmasters would be even better.

    When doing your flow calculations, is there a way to take intake, fuel to air ratios and exhaust flow into consideration to make a more precise determination?

    I don't have a text book to calculate flow, but with regard to off road motorcycles, I can tell you from personal experience that increasing the flow of air intake, properly mixing the air to fuel mixture and making the exhaust less restrictive makes big improvements in performance. Exhaust is a very important element as opening up the exhaust too much will also reduce HP and torque. It has to be balanced as do the other two elements.
  • lwflwf Member Posts: 223
    That was a good post richflynn. When I started to read it, the first thing that came to mind was 'why doesn't K&N put that kind of information in their web site instead of the baloney that I saw there?' By the time I finished reading what you posted, the answer seemed clear....it's aimed at racing buffs rather than the average driver who, as you said rarely go over 5400 rpm.

    I'm not sure I know what you mean when you say adding flowmasters behind the catalytic converter. I've seen articles about putting a sensor in the exhaust to measure the products of combustion and using that data with a reprogrammed chip to fine tune the incoming air mixture. It seemed like a far-out concept to me, so I don't think I would be interested. But is this the kind of thing you are referring to?
  • stanfordstanford Member Posts: 606
    Cat-back systems (replacing stock exhaust behind the catalytic converters) are quite common, and helpful. They generally make your engine more efficient, thus increasing power and economy. However, they're quite a bit more than a new filter. If you have a common vehicle, they'll run you anywhere from $200 up to whatever you care to pay.

    Free flowing exhausts can work wonders, even on nice diesel trucks. Gale banks has some good systems for the '97 power strokes, and I'm assuming they'll come out with models for the SDs shortly.

    Their exhaust kit for Fords with a 460 gained 68 hp, 85 lbft torque, and 15% better mileage. These are off their website, but they sound fair to me (a good exhaust system, including headers, can work wonders). To answer the inevitable question, factories don't use them on mass-market vehicles because they're harder to install, more expensive than manifolds, may wear out faster, and most people don't care.

    Want more info? Check out their website:
  • lwflwf Member Posts: 223
    Thanks stanford. That's pretty impressive but somewhat different from what I thought it might be. Is "flowmaster" another name for the system Banks describes, manufactures and sells?
  • stanfordstanford Member Posts: 606
    Nah -- Flowmaster is a (very good) brand of mufflers. The company may also produce other components, or full systems, but many people make setups designed for (and including) flowmaster mufflers.
  • akjbmwakjbmw Member Posts: 231
    I saw one of those windage trays shown in an edition of HotRotTV on a racing motor they were preparing. I thought their explanation was related to stripping the oil accumulation that winds itself around the crankshaft adding to the moving mass. Another one of those features that have been developed in the racing world, yet may not provide a significant difference in our daily or Sunday drivers.
    I wonder if their writers thought the /wind/age referred to "wind" as in yarn instead of "wind" as in strong breezes?
  • lwflwf Member Posts: 223
    So that's all Flowmaster is, just another brand of muffler. Boy, am I embarrassed.

    Before I asked, I had tried www.flowmaster.com and something came up that indicated some kind of software package for the analysis of temperature, pressure and flow distribution. I guess fluid flow is a hotter topic than I thought.

    Oh well, thanks for the info.
  • sato8sato8 Member Posts: 7
    I just install my K&N filtercharger today ,it feels the same but I already Had my cat back exhaust installed its a proline similar to flow master but not as loud until you nail it, I'll report back on my 98 dodge ram 5.9 liter as to the milage currently I'm getting 12.5 combine city and highway(mostly city).north Ca. area on 89 octane gas. I have k&n's in all my motorcycles but like Jim2 said it was part of an overall upgrade, exhaust, re-jetting the carb, because if you just put on a high flow air cleaner the bkie will run extremely lean and will run terribly..
  • jim2jim2 Member Posts: 43

    The new auto engines have fuel injection and sensors all over the engine. With our dirt bikes and carbs there are no sensors to worry about.

    Will the auto engine sensors pick up the fact you have increased air intake, with your K&N, and decreased exhaust back pressure, with your cat back exhaust, and adjust the fuel to air mixture in your fuel injection system? Do K&N, Flowmaster or cat back address a cradle to grave approach to making modifications to intake, fuel mixture, sensors and exhaust?

    As you said, just modifying the air cleaner can actually make an engine, at least a motorcycle engine, run worse without also modifying the rest of the system.
  • cdeancdean Member Posts: 1,110
    all the new, fuel injected engines have enough sensors all over them, including exhaust oxygen and intake oxygen. i would assume that it would adjust itself.
  • sato8sato8 Member Posts: 7
    Well took me a little while but my milage did increase a little getting 13.2 mpg more noticeable power when I nail it and sounds really good reminds me of my hot rodding days (70 dodge 440 magnum challenger) as for adjustments none were needed idle the same, the only thing I noticed were a air sucking sound almost like an out of adjustment fan belt type of noise(at 2100 rpm only), I had my mechanic check it out he said it was normal for that air cleaner but got used to it pretty quickly, only took about 20 minutes to install the whole unit.
    the next thing I think I am going to try out is a hot ignition like Jacobs ,Crane,or Nology I hear they work in improving mpg and power, anyone have more info on any of these products?
  • cdeancdean Member Posts: 1,110
    what did you put on sato8, and air cleaner, or performance kit? what did you put it on?
  • sato8sato8 Member Posts: 7
    the filter charger kit about 120 bucks, remove old air cleaner and haedware and replace with filtercharger kit all neccessary hardware is included.
  • jim2jim2 Member Posts: 43
    I recently read an article about an air induction kit from a company called "Stillen" in Costa Mesa California. They use the K&N air filter and replace the stock air cleaner and plastic. They take the air flow sensor and "on board computer" into account with their design.

    Anyone out there used this product and if so how do you like it?
  • sgerbear1sgerbear1 Member Posts: 1
  • stitches98stitches98 Member Posts: 1
    I Just Purchesed A 94 Ext-Cab Dually With A 6.5 Turbo Diesel And Wanted To Know If Any Body Else Is Having The Same Problem That I`m Having. Between 3000-4000 RPM The Engine Starts Bucking Real Bad, Until You Let Up On The Throttle A Little Bit And Then Smooths Out. Can`t Push Hard Against Throttle Fast. O.K. If Throttle Slow. Does Anyone Make A Chip For The ECM That Will Fix The Problem.
  • stanfordstanford Member Posts: 606
    Wow. Just out of curiosity, how high does Chevy have the redline on those diesels? My '93 Ford redlined at 3300 and a rev-limiter kicked in at around 2900.
  • pstoutepstoute Member Posts: 3
    Just bought a '99 Ram V-10 and I'm interested in giving it the most clean air available, a K&L filter kit has been recommended. Does anyone know if this kit effects mfgr. warranty?
  • tlippytlippy Member Posts: 8
    K&N Filters. I just bought a Dodge Diesel and asked the local Cummins outlett about the K&N. They commented that it is their experience that when they remove the air cleaner for maintenance, the K&N had a lot more dust and crud on the inside than the OEM filter. If you buy the oils and cleaners from K&N, there is very little savings over the OEM filter. The Cummins guy said there is no way to get more free air without bigger openings. Bigger openings allow more debris to pass. You can debate this subject to death, but I"M not going to buy a K&N. Tom
  • stanfordstanford Member Posts: 606
    Actually, one of the proported benefits of the K&N is that the oil-soaked filter will retain particles that the standard ones let pass. Thus the filter itself may look dirtier than the regular ones. Quoting from the K&N Website if I may...

    Conventional filters use paper or foam material permeated with millions of tiny, irregular passages, that screen dirt particles out of the air. Because the dirt particles are trapped inside the passages, they eventually clog; and when this occurs, airflow restriction increases dramatically.

    With the Filtercharger®, a special cotton fabric is sandwiched between the pleated aluminum screen wires. The pleated design provides five times more filtering surface over the element circumference. The cotton/screen wire filter media is then saturated with a formulated air filter oil.

    Acting like a fluid curtain, this oil attracts particles of dirt and debris which build up on the outside of the filter. This buildup of dirt particles suspended in oil creates more and more irregular passages that actually create an additional filtering barrier with use. Not until very fine particles close this secondary "filter layer" does the filtercharger begin to clog.

    In most cases, up to 1/8" of dust can cover a Filtercharger® before performance is significantly affected. On a street driven vehicle, a Filtercharger® can last up to 50,000 miles before service is required. Then, because it's made of reusable materials, you can just clean it, apply fresh K&N Filter Oil and Re-install.

    Of course, this is all just so much marketing literature. Still, I've not known too many people (if anyone) to buy them and then complain.
  • arazaraz Member Posts: 27
    What a whole lot of tech talk, and advertising here. The first things that get added to my pick-ups and SUV's (RAM 1500-Ranger-Suburban currently)
    is a K&N filter and a Borla exaust system. For economy? Nope. For performance? Maybe. For the sheer pleasure of being able to hear my engine again. Yup. Call it second childhood or midlife crisis. I think most folks do it for the same reason!!
  • mstegallmstegall Member Posts: 2
    Well, the "sucking" noise that my K&N Filter didn't turn me on that much. As of yesterday, my stock air filter replaced my K&N on my '98 Dodge Cummins. Until someone besides the K&N people say that this filter is OK to use on my Cummins, I am not willing to take the chance on this filter because there is no proof that K&N filters out enough debris. I sure don't want to be replacing my turbo. Most engine experts that I have talked to (non-biased) say you are wasting your money on the K&N and its not worth taking the chance on air filtering problems.
  • cobra98cobra98 Member Posts: 76
    I just watched a show yesterday (can't remember the name!!), but it's on every Sunday and consists of two guys working on cars. This weekend, they put in a new camshaft and what looked like an Edelbrock intake. When they were putting everything back together, they put on a K&N air filter and said that it has much better air filtration and adds some hp to the engine. Don't know if they know this or if they assumed it based on K&N's claims (or maybe K&N was a sponsor...)

    Just my $.02
  • markbuckmarkbuck Member Posts: 1,021

    paper filter= least flow, most filtration
    foam filter= most flow, least filtration
    gauze type(K+N)= more flow than paper, poorer filtration. Less flow than foam, better filtration.

    It's ya'lls choice.............
  • RichRich Member Posts: 128
    Let's put the quality of the filtration issue aside for a moment and consider airflow.

    I've looked at the K&N literature and from their own charts and graphs the following:
    Air flow is increased
    Horse power is increased
    These benefits are minimal until significant engine RPM has been achieved. In a gasoline engine, the 10% or so horse power gain is around 5000 RPM.

    The questions are:
    How often do you need this horsepower gain?
    Are you willing to run your engine at 5000 RPM to achieve the horsepower gain?

  • stevekstevek Member Posts: 362
    The K&N air filter for my truck cost $55.00. The original equipment filter from the dealer cost $35 dollars and need replacing every year. So performace or not in the long run the K&N filer was cheaper.
  • wandrrwandrr Member Posts: 13
    Even if you add in the cost of the cleaner and filter oil (it is really easy to do-it-yourself clean and re-oil the filter) eventually the K&N will be cheaper. Assuming you will keep the vehicle for more than three or four filter changes or so, the K&N will be cheaper. This of course depends on the cost of either alternative (variable for different vehicles), but sooner or later the K&N will be cheaper.

    PROBABLY there is some performance advantage with the K&N, but the cost was the deciding factor for me.
  • cobra98cobra98 Member Posts: 76
    for me, cost wasn't an issue (a few hundred bucks over many years is negligible).

    Do I like to live around 5000rpm? For my Mustangs, yes. For my F150 I will (after the new engine is put in next month). So, if there is true power to be had around the 5000rpm limit, count me in!
  • markbuckmarkbuck Member Posts: 1,021
    steveK and wandrr - since you all seem to work for free (cleaning nasty old air filters) was wondering if you all would come over to my house and fix my septic system..... I'd pay for the parts.

    Me, I'd rather buy a paper filter and spend the extra time playing.
  • stevekstevek Member Posts: 362
    I do my own maintenace on my vehicles and save enough money to pay for someone else to fix my rotten septic system. Thank for the offer anyway.
  • quadrunner500quadrunner500 Member Posts: 2,721
    I have the K&N filtercharger kit on my '94 Z28. It relplaces the stock air box, and draws cooler air from the bottom of the car. Still the gains, if any, are not something I feel in the seat of my pants. I have a hypertech programmer that alters the spark and fuel curves. Can't feel it either. But together, they took about a tenth off the quarter mile, so the clock knows. I have worried that maybe the filtration is no picking up the smallest particles as before, but who knows? I think the best filter is the oiled foam one on my dirtbike. The carb throat is always very clean, no matter how much fine dust combined with crud gets on the outside.
  • thinmanthinman Member Posts: 18
    This was an interesting read for a rainy afternoon. Thanks All!
    I bought a K&N Air Fliter for my (then) new '95 S-10 with a 4.3 TBI engine. I had owned the truck for 6 months by that time so had a good 'seat of the pants' feel for how it proformed. One kick I had was the lousy throttle response. It was like I had to call Western Union to send a telegram to the engine! "Pay attention up there...we're going to accelerate now!"
    After I installed the K&N I backed out the drive to run an errand for the wife. When I hit the gas like I usually did, I chirped the rear tires! Talk about surprised! Was this a dramatic increase in horsepower? Hell if I know. All I know is that I now have much better throttle response at all RPM ranges and vehicle speeds than I did with the OEM filter.
    As for gas milage changes I can't tell you about that. I usually just drive around town and with the traffic the way it is here my mileage is always fluctuating anyway.
    And one side note. I kept my last S-10 for 13 years and I intend to do the same with this one. So if I only buy one air filter (at $39.95 btw) vs 5-10 over its lifetime, what have I lost?
  • JTOJTO Member Posts: 28
    In my mustang ('90 5.0) I noticed a difference in the seat-of-my-pants with the K&N. For the $10(used) I spent, IT WAS WORTH EVERY PENNY! Now in my '95 Dodge Ram (1500, 5.2L), it's not as noticable... my mileage went down slightly,though (just under 1 mpg). For the $45(new) I spent it has paid for it self (barely :)
  • JTOJTO Member Posts: 28
    ....I ment the mileage went up.
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