Lower restriction filter / cold air intake = better MPG?

Discussion in 'General Motoring' started by Charles Lasitter, Apr 8, 2006.

  1. (aside from the obvious tips on driving slower ...)

    I've read a number of posts suggesting that a low restriction
    cotton-gauze filter can marginally increase fuel economy and power.
    I've heard other speak in favor of mods like cold air intake, headers,
    cat-back exhaust providing marginal benefit.

    Assuming that the maintenance is all kosher and the proper driving
    techniques are in place, what mods (in the few hundred dollar range)
    would hold some promise of delivering improved fuel economy for an '05
    Accord LX i4 M5?
    | Charles Lasitter | Mailing/Shipping |
    | 401/728-1987 | 14 Cooke St |
    | cl+at+ncdm+dot+com | Pawtucket RI 02860 |
    Charles Lasitter, Apr 8, 2006
  2. Charles Lasitter

    Eric Guest

    Perhaps, but then you might shorten the engine's life span since you could
    be reducing the filtering capacity of the intake system. If I remember
    correctly, there have been some posts on this newsgroup of people stating
    that their engines have starting to burn oil after driving around with these
    "low restriction" intake systems for a while.
    Eric, Apr 8, 2006
  3. Charles Lasitter

    Brian Smith Guest

    That could be one of the reasons every time I am behind one of the garbage
    can muffler equipped cars, that I either smell the odour of burning oil or
    am at a loss as to where the road is due to the cloud of oil smoke in front
    of me.
    Brian Smith, Apr 8, 2006
  4. I'm not having that much luck finding empiracle data on this topic,
    but this test of K&N filters was a start:


    The subject is not without controversy, but I'd love to see more
    references to careful testing of the filtration and performance gains.
    | Charles Lasitter | Mailing/Shipping |
    | 401/728-1987 | 14 Cooke St |
    | cl+at+ncdm+dot+com | Pawtucket RI 02860 |
    Charles Lasitter, Apr 9, 2006
  5. Charles Lasitter

    L Alpert Guest

    We use the endearing term "Honda Turds"....
    L Alpert, Apr 9, 2006
  6. Charles Lasitter

    doug Guest

    Cold air intake can help increase HP - but also uses more fuel to do it.
    Unless the efficiency of the engine has magically improved, you need to put
    more energy (gasoline) in to get more energy (HP) out. When you consider
    that the engine in your '05 has been finely tuned to give you the best
    balance of power, economy and driveability, it's hard to imagine that any
    aftermarket bolt-on can do it better. My 2 cents worth.

    doug, Apr 9, 2006
  7. Charles Lasitter

    Brian Smith Guest

    Fortunately, it's not only Honda products that have this problem.
    Brian Smith, Apr 9, 2006
  8. I think you're largely correct, but it's worth bearing in mind that they
    are engineering the car for the needs of a mass audience and doing so at
    the lowest possible cost.

    So in theory, at least, if you were willing to spend hundreds more on
    the exhause system, or the air intake system, or another wad on the
    suspension system, you might get a car more to your liking in terms of
    specific aspects of performance or handling.

    If a selective investment gives me a little better fuel economy, or a
    little better performance at the same MPG, I'll take that as a win. At
    least until I win the lottery, and then I'll forget about all the
    tweaking, and just pop for a Beemer 550i.
    | Charles Lasitter | Mailing/Shipping |
    | 401/728-1987 | 14 Cooke St |
    | cl+at+ncdm+dot+com | Pawtucket RI 02860 |
    Charles Lasitter, Apr 9, 2006
  9. Charles Lasitter

    Jim Yanik Guest

    WRT cold air intakes,they generate a lot more noise,and auto engineers are
    designing for a larger market that would not tolerate the extra noise.
    The same goes for low restriction exhaust systems.
    Jim Yanik, Apr 10, 2006
  10. Charles Lasitter

    TeGGeR® Guest

    Here's a better one.

    A K&N filter will allow lots more dirt into your engine, grinding your
    rings, bores and bearings much more quickly. It will increase the amount of
    abrasive silica in your oil. It will gum up the IAC/EACV much more quickly.

    Any performance gains on a road-going Honda are likely to be measurable
    only with a dynamometer. Hondas, like most small-capacity 4-cylinder
    engines, do not have excessive intake restriction to begin with.

    See my link above. I would NEVER use a K&N on ANY Honda that I intended to
    make last for a long time.
    TeGGeR®, Apr 10, 2006
  11. Everyone agrees that dirt in the oil is bad, and the URL you provided
    has information in the form of graphs, which is useful, but here's the
    question I have trouble with:

    Both had tests with ISO 5011 standards, and page I found used other
    standards for additional tests, and the results quoted there cast K&N in
    a more favorable light.

    So what are the key differences between the tests, and what is the rate
    of filtration that Honda sets as "good enough" for its engines? How
    does the factory issued filter perform?
    | Charles Lasitter | Mailing/Shipping |
    | 401/728-1987 | 14 Cooke St |
    | cl+at+ncdm+dot+com | Pawtucket RI 02860 |
    Charles Lasitter, Apr 10, 2006
  12. Charles Lasitter

    jim beam Guest

    why don't you address the real point? hondas don't have restrictive
    intakes unlike say a 5.6L dodge whose ducting is narrower than a 1.5L
    civic. "cold air" is mostly unnecessary unless you're right at the top
    of the power band. and even then, in my experience, most people that
    consider themselves hot-shots off the lights change /way/ too early and
    /never/ get into a rev range where there could be any advantage. [not
    counting the stock system's advantages of resonance tuning of course.]

    i gun my [motor all stock] civic pretty hard, use the full rev range,
    and guess what, i can drag most riced civics up to about 60. why?
    because i have everything adjusted perfectly, /not/ because i ponce
    about with a stupid air intake that i don't need. save your money - use
    oem filtration and enjoy both better mid-range performance and longer
    engine life.
    jim beam, Apr 11, 2006
  13. Of course, any gasoline engine running at less than wide-open throttle has
    intake restriction, regardless of the air intake or filter... it's called a
    throttle plate. Any benefit of intake or exhaust mods can only be felt at
    full throttle and high rpms. I've never understood the attraction myself.

    Michael Pardee, Apr 11, 2006
  14. Charles Lasitter

    Jim Yanik Guest

    I guess you never have removed the intake on one.They are restrictive AND
    suck hot underhood air.The intake makes all sorts of turns,has a resonator
    tank,and the final duct to the throttle body is corrugated,not smooth.

    Again,not true.I got much better low-end performance on my 94 Integra
    GSR,with a $60 chinese CAI off Ebay.It's filter is as good as the OEM
    filter.IIRC,they use the same material.
    You could feel the difference in performance.
    Jim Yanik, Apr 11, 2006
  15. Charles Lasitter

    Jim Yanik Guest

    to add to my previous post;Honda Tuning Magazine flowbench and dynoTESTED
    CAIs and short ram intakes and documented the power and torque gains.
    With a benchmark test of the OEM system to compare against.
    Jim Yanik, Apr 11, 2006
  16. Charles Lasitter

    Jim Yanik Guest

    altering the length of the intake alters the HP and torque at any given
    RPM,and ingesting colder air allows the ECU to add more fuel,making more
    power,regardless of what RPM.
    Honda Tuning Magazine's dyno test graphs showed that,in their intake
    systems testing a couple of years ago.
    Jim Yanik, Apr 11, 2006
  17. Charles Lasitter

    doug Guest

    You're missing the point of the OP - he wants a little more power and a
    little better economy. If "colder air allows the ECU to add more fuel" he's
    going to lose MPG, not gain. The point of whether or not he gets more HP out
    of a CAI is moot.

    doug, Apr 11, 2006
  18. In addition to the advertising hype there are obviously different
    opinions on the issue of filters and CAIs, and this exchange of views is
    almost exactly what I was hoping for.

    I'm really not expecting any of these mods to pay for themselves in
    terms of fuel economy, and I am not interested in HP gains that are so
    small they can be measured on a dyno but not felt.

    The factory setup is almost always going to be best for the largest
    number of drivers, and I appreciate your comments.

    One thing I find curious is the absence of CAI listings for '05 2.4L
    Accords. I was just out trying to follow the air inlet path, and it
    seems to end just forward of the drivers front wheelwell.

    It's shielded, no doubt to protect against water ingestion, but it seems
    that this location would normally provide it with a source for
    (relatively) cold air.
    | Charles Lasitter | Mailing/Shipping |
    | 401/728-1987 | 14 Cooke St |
    | cl+at+ncdm+dot+com | Pawtucket RI 02860 |
    Charles Lasitter, Apr 11, 2006
  19. Charles Lasitter

    Jim Yanik Guest

    You don't get increased power AND increased fuel economy at the same time.
    However,having more power output at a given throttle opening,you can back
    off on the throttle and use less fuel and not suffer a performance
    loss(from original).
    With the added benefit of having more power available when wanted.

    IMO,driving -style- is more influential on fuel economy,gentler starts and
    coasting when possible do more for fuel economy than any mods.
    Sure,he could strip out excess weight like insulation,unused seats,clean
    out the trunk,no spare tire,but that's impractical.(and unwise)
    Jim Yanik, Apr 11, 2006
  20. Charles Lasitter

    Jim Yanik Guest

    Honda Tuning Magazine's tests got 20 hp gains on an RSX with the CAIs,5-7
    hp with short rams.I could definitely feel the gain on my GSR after the CAI
    was put in. IMO,a short ram was not worth the trouble or cost.
    Like in my Integra,you may find that the intake curves UP into the top of
    the fender and back into the engine compartment,along with a resonator tank
    in that wheelwell area.The Type-R difference is that the pipe ends at the
    top inside of the fender,not reentering the engine compartment.The length
    of the intake piping increases low-end torque,I've read.

    Not when the pipe loops back into the engine compartment.(like my Integra)

    One Integra modder had a diagram of the Integra intake plumbing on their
    website,and a copy of the Type-R's intake,too.
    Jim Yanik, Apr 11, 2006
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