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K&N air filter = better gas mileage

Discussion in 'The Lounge' started by pixelninja, Aug 31, 2005.

  1. pixelninja New Member

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    For all those that want to save a little money on gas, here's a simple thing you can do to increase your gas mileage without much effort: Go to you local auto parts store and buy yourself a K&N air filter. These filters are different than your typical air filter and allow a lot more air into your engine, increasing both horsepower and gas mileage.

    I drive an '03 Toyota Tacoma. Up until now, the best gas mileage I ever got was around 19 mpg, and that was 100% highway. Last week I went out and bought a K&N air filter. This morning I filled up for the first time since installing the new filter. By my calculations, I got 20.5 mpg. And that was driving apprximately 60% highway, 40% city. I won't know what my true highway gas mileage is until my next road trip, but I can guarantee that it'll be higher than 20.5 mpg.

    The initial investment was a bit more than a regular filter. I paid $60 for the filter and recharger kit, whereas a typical filter for my truck runs around $15-$18. This thing is, I will never buy another filter again. These filters are guaranteed for 1 million miles and all you have to do is clean them once every 30K miles or so. I only need to keep my truck for another 80K miles before I've saved money simply on filters, let alone gas. And I definitely plan on keeping this truck until it dies, which could be a couple hundred thousand miles from now (I currently have 53K on it).

    These filters won't double your gas mileage, but with prices the way they are now, every little bit helps.
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  2. N8 v2.0 Not the sharpest tool in the shed

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    I used one for about 5 years, but went back to the stock Toyota filters because they filter better.
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  3. SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    If properly maintained, that Toy oughta last you 1/2 million miles. :thumb:
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  4. jacksonpt Active Member

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    FWIW... there are numerous studies that show K&N air filters do a sub-par job filtering the air.
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  5. Hawkeye New Member

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    I would be willing to try it out on my wifes Jeep but I am to broke from putting gas in it to buy another filter.

    I think I may bite the bullet and fill her tires up to 35lbs put in a K&N and see how much better the milage is over a couple of tanks.
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  6. SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    Well, how in the heck do you think they get all that air in there? :D
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  7. Westy the teste

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    Most people do not have their tire pressure set properly and can see 10% gains in mileage by doing so.
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  8. JRB Guest

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    I need to check my air.
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  9. Raaar New Member

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    I used a K&N for a while & went back to a stock filter. The filter itself will not make much difference. I did, however, see pretty significant gains(1-2mpg & ~10 hp) with a cold air induction, intake & exhaust porting,headers, and a better exhaust system.
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  10. SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    Ahhhhhahahhahahaha. How much gas could you have purchased with the money spent on those mods? :think:
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  11. Westy the teste

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    I can't help but to think the K&N filter improving mileage is a bunch of crap. The filter allows more air to flow, more air requires more fuel. Unless this is confusing the cars computer and causing a leaner burn. So your engine is getting more air and fuel so you don't open the throttle as much and end up burning the same air and fuel you were before. Now you could argue that the engine is not working as hard to pull air through the filter but since your throttle is closed more it has to work harder to pull air through the throttle body.

    What is probably happening is you have now been more concerned about mileage and are driving differently. Don't accelerate as hard and you burn less gas. You can also run more efficiently by shifting earlier, most engines are actually most efficient at low rpm's with a wide open throttle.
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  12. N8 v2.0 Not the sharpest tool in the shed

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    I've got 203,000+ on my 1997 4Runner!

    :D:D:D
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  13. pixelninja New Member

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    Can you show me links to some of these studies? I'm genuinely interested and I don't want to do long term damage to my truck. If I've made a mistake, I'd like to know. I did a bunch of searching online before I bought the filter and only came up with anecdotal stuff, which was then refuted by more anecdotal stuff, but I didn't find any hard data saying that K&N filters would damage my motor.

    I've been driving differently for several months now, and I'm positive that this last tank of gas lasted longer.
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  14. N8 v2.0 Not the sharpest tool in the shed

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    I know there was a lot of info on the Toyota BBS a while back. Mostly applies if you live in an area that has a lot of dirt and dust in the air like the southwest etc...
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  15. jacksonpt Active Member

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    I read a lot of stuff back when I cared about my truck. I don't have any of links anymore, but a lof them were posted on toyota BBSs... I'll see if I can dig them up.

    FWIW, there are about a zillion things that can affect gas mileage - the fact that this tank of gas has lasted longer may or may not have anythign to do with an air filter. It looks like my current tank of gas is going to last me about 30 miles more than normal, and to my knowledge, nothing is different from this tank compared to the last 50 tanks I've run, but for some reason, my gas mileage is up noticably.
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  16. pixelninja New Member

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    I'd appreciate that... :thumb:
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  17. SilentJ trail builder

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    I think this is, actually, the case. After all, an engine is just a big air pump.

    I installed a straight through Magnaflow muffler on my truck and saw a 1-2MPG improvement over the OEM muffler. Then I installed a K&N FIPK (basically a cool air intake) and I saw another 2-3 MPG over the aftermarket muff. This setup sounds friggin wicked so I end up driving a lot harder and still get better mileage than before.

    As for the filtering, as long as the filter is properly oiled, then I haven't seen anything to convince me that it will hurt my engine. The danger is when the filter is improperly cleaned and left un-oiled that it will filter like crap. On the flipside, if the filter is over-oiled then that oil can coat your MAF sensor and throw a code that will give you a check engine light <- at least on my truck...Im sure it can do other things to other vehiculars as well.
    #17
  18. DRB unemployed bum

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    get to the top you stinkin' gas thread
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  19. Crashby Member

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    I just purchased a K&N filter for my '99 Accord on EBay for 39.95 shipped! :)

    Thanks for the tip!
    #19
  20. Potroast88 YouTube Boy

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    K&N filters are subpar because they are made from gauze and allow larger particles through into your engine. The best filters on the market are foam. They allow the same amount of air to flow and do a much better job of filtering. Check out www.trueflow.com.
    #20
  21. ALEXIS_DH Tirelessly Awesome

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    not really.
    the foam gets "brittle" and "cracks" when it gets old, and then little particles of the foam, alongside other particles get sucked into the engine...
    #21
  22. ALEXIS_DH Tirelessly Awesome

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    i was talking about this with my auto mechanics teacher the other day.
    he was explaining mem when i asked why i got better mpg with 97 oct than with 90 oct.
    and a paralel can be drawn here.
    if there is more air to burn by a given throtle position, then you get more power.
    even if the ecu sends more fuel to burn, its more thermically efficient in most cases to burn 1 unit of air at a given temperature at say 3000 rpm... than to open the throtle more (which sucks more air, but raises the rpm) and burn 1 unit of air at a given temperature at 4500 rpm.
    since you get more power sooner, you step less on the gas. the throtle opens less and you stay more time within the optimal rpms for thermal efficiency by reducing the need to burn gasoline at higher (and less efficient) rpms to get the same power. of course, assuming you upshift at over 2000-2500 rpm...
    #22
  23. pixelninja New Member

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    Not based on what this guy says:

    http://www.bobistheoilguy.com/airfilter/airtest1.htm

    Per his tests, a K&N cotton gauze filter is superior to an Amsoil foam filter for both filtration AND flow. He also goes on to say that cotton gauze is the best for airflow and paper is the best for filtration. Take his tests for what they're worth...some guy doing his own tests in an uncontrolled environment with debatable results.

    A guy in this thread (http://p073.ezboard.com/fspeedtrapfrm29.showMessage?topicID=140.topic) says he drove a CRX for 494,000 miles with a K&N filter in it.

    Since I posted this thread and got the replies that I got, I've scoured the net looking for info. I've pretty much found 2 sets of people, the "oh my god its going to ruin your engine (or so I heard)!" crowd and the "I've ran K&N filters for the past 10 years and haven't had a single problem" crowd. 90% of what I've found is hearsay. The other 10% is anecdotal.

    Maybe my improved gas mileage was all in my head. Maybe not. All I know is I don't think I've ever gotten over 20 mpg before. Maybe I wasted my money. Maybe not. For now, I'll keep running my K&N and not worry about it.
    #23
  24. Potroast88 YouTube Boy

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    The foam will not get brittle and crack as long as you clean it and oil it like you are supposed to.
    #24
  25. DRB unemployed bum

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    Gas Gas Gas Gas Ranch Gas Gas Gas
    #25
  26. Spitfired New Member

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    So, I've been thinking very hard about installing a Turbo in my CR-V. If I can get everything I need from the right places, this will cost me under $500. Now, assuming a conservative 40% increase in horsepower I'm thinking I could improve my milage quite a bit if I drive as I do already. My criv's engine is deffinitly underpowered for the car (its are 130~140hp I beleive) so I find that it needs to rev VERY high (4500 to 5500 range) for a smooth acceleration, and forget about going up hills. That's a nightmare.
    I love the car though. It handles great, it's reliable, and it's really quite efficient already, but do you think a turbo would help things? If the end result is 200hp, I would think that I could keep the rpms a lot lower and the engine wouldn't need to work nearly as hard.
    #26
  27. ALEXIS_DH Tirelessly Awesome

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    i really doubt you could pull that for under 500.
    just the turbo alone will run at least you that much. then if you think about the new manifolds you´ll need new or improved injectors, pumps, ecu, pipes, welds, an intercooler... and that is assuming your na pistons and compression can take that, which is highly unlikely.
    and even if you pull it out, your cv joints and the engine mounts would probably not chew nicely an extra 40% hp on your crv, thus reducing you ability to put it to the ground...
    #27
  28. James | Go-Ride New Member

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    I can vouch for MPG and HP improvements with the K&N filter. I have an '04 Silverado (and, hence, no money for food and drink PBR, not that there's anything wrong with that) and I went from averaging 14 and 18 (with the fuel test, not according to the computer) to 16 and 20. I haven't put the whip on a dyno to test the HP and torque gains but my accelleration increased notably and I can pull longer on inclines under load. I hadn't heard about any problems with K&N filters, my guess would be those were rumors started by Amsoil and other competing companies.
    #28
  29. Spitfired New Member

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    Hrm. you're right.
    I'm just gonna design some sort of sick nasty air intake then.
    #29
  30. dexter Active Member

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    go with an amsoil much better foam filter. kand n's let in to much **** and cost too much
    #30
  31. beestiboy New Member

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    K&N 1mpg better
    tornado in the intake 1.5mpg.

    2500 mi of tracking the mpg for each piece installed and prior to either piece installed

    45000 mi so far with both installed saved me so far 250 gallons of fuel (now average 22.5 vs 20) you can do the math for savings in your area, i have payed roughly $2.50 in the bay area over the last year and a half Thats about $625, plus it feels like the car is more powerfull over all. My investment was about $125 for both and an additional $15 per year for the cleaner and oil. I dont plan on having the car at 200,000 mi so if it does do damage oh well.
    #31
  32. teambender New Member

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    I put a K&N in my GTI and I also noticed an improvement in MPG.

    But I do have to say the old paper element looked like someone tried to build a sand castle in it.
    #32
  33. ufdff15 New Member

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    i also noticed that i was getting better mileage and more power. Full Syn Oil also helps with mileage.
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  34. manhattanprjkt83 Rusty Trombone

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    first thought as well... :think:
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  35. luken8r New Member

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    i dont believe anyone who says the k&n setup allows more crud into the engine

    i have one on my ZJ. earlier this month while up in maine i was on this dirt road following someone else for ~35 miles or so. this was a well maintained dirt road but was also VERY dusty, especially fowllowing someone else for this distance. the dust got everywhere, teh real fine stuff was all over the interior, after working through the HVAC ducts (windows were up) and the exterior of my jeep was no longer red. so after the 70 mile round trip on this road, i get back and crack open my air intake. i take the filter off and the engine side of the intake was bone dry and not a speck of dust to be found. with the very fine particules all over the exterior and interior of the jeep, i would though that something would have gotten through, but it was 100% clean. take it with a grain of salt, but in my experience it is perfectly safe and a good filtrate
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  36. Raaar New Member

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    Is it cost effective? Gas is hitting $5 a gallon in some places. If you can increase your mileage by 10% you cut your effective gas cost by $.50 per gal (at $5 per gal). If you have a 20 gal tank you recoupe $5 every time you fill up completely. At that rate you could recoupe your money fairly quickly($20 savings per mo=$240 in the first year).

    btw, the vehicle I was refering to was an old CJ7 that I installed a TBI 350 in, as well as on OD transmission, 3/4 ton axles, and a bunch of other crap. Needless to say, it wasn't built to be economical. But even with double the HP of stock, much larger tires, and increased wind resistence, my gas mileage actually went up 2 mpg over the original 6 cyl.
    #36
  37. SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    :think:

    Ummm....... you're being pretty generous to your argument by assuming gas is going to cost $5/gallon in perpetuity.

    How much did those mods cost?
    #37
  38. James | Go-Ride New Member

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    Gas has been over $5 per gallon for quite some time throughout most of Europe and the Pacific/Australia. The US is going to catch up at some point, and I can't recall any period in US history when energy prices actually dropped on a long-term level after catching up to inflation and more globally-equated levels.
    #38
  39. SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    But why is that?
    The US will never catch up to Euro gas prices unless one of two things happens.
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  40. pixelninja New Member

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    If the oil barons of the world have anything to say about it, it will. I'm sure they'll come up with all sort of excuses to explain the high prices and eventually the sheep, er, population of the US will just get used to it.
    #40