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  1. Join Date
    Oct 2002
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    4,801
    #21
    mbt, found a posting from another website and you are absolutely correct. Not that I ever doubt you, hahhaha.

    Listen, I think some of you are putting too much meaning on the word "overdrive." A three-speed automatic tranny with "overdrive" and a four-speed automatic tranny are the same thing, OK? Just as a 5-speed manual can be called a four-speed with "overdrive."

    Overdrive = top gear. 3+1=4, and 4+1=5. The word "overdrive" is a marketing gimmick from the '70s when 3-speed automatics ruled the U.S., and manufacturers wanted some special name to put on their new 4-speed automatics to make them sound magical and different.

    The point I'm trying to make is that most cars with FIVE GEARS have better highway mileage than cars with FOUR GEARS -- no matter what you call the final gear. More gears usually equals a lower final drive ratio in the top gear, making the engine turn fewer rpms per mph and resulting in better fuel economy. The Mazda Protege's 5-speed ("4 speed with overdrive" if you must) box was geared for high revs to make for peppy acceleration with its 125-hp engine; therefore it's not as fuel efficient at highway speeds as the 4-speed (er, "3-speed with overdrive") automatic tranny.
    A/T and M/T MZ3:
    Come to think of it, the Mazda3 manual tranny's top 2 gear ratios are less than 1:1. That's part of the reason I got that cool manumatic instead.
    Last edited by Karding; July 11th, 2005 at 11:39 PM.

  2. Join Date
    Dec 2004
    Posts
    430
    #22
    Quote Originally Posted by mbt
    wala naman gaanong relation yung torque sa fuel mileage... if ever, it's higher torque tends to have poorer mileage, because the factors that create big torque (e.g., displacement, forced induction) also increase consumption. on the other hand, for others, low torque and low displacement nga, pero binabawi sa revs (i.e., Honda engines)... so end result is that malakas din sa gaso at those revs.

    the amount of fuel that the engine drinks is directly related to displacement (big cylinder needs more fuel injected into it) or revs (squirting X ml of fuel 5000 times a minute is of course a greater total volume than X ml of fuel squirted 2000 times a minute). that's why shorter gearing kills mileage (kasi mas mataas yung revs at the same speed).

    diesels are a different matter though.
    yung sinasabi ko in relation with toyota and honda

    toyota has higher torque compared to honda

    and masmabilis ma achieve ng corolla ang peak torque nya compared to civic (low rpm high torque ba yun)

    i dont know the case about mazda 3
    parang in between siya ng civic at corolla

    kasi mapapansin natin yung mazda 3 2.0 has lower hp compared to civic 2.0 but has higher torque as for corolla 1.8 has lower hp than mazda 3 but has higher torque diba

    so ang pinaka oks sa consumption is corolla (sabagay 1.8 lang siya), and as for the 3 and civic halos pantay lang

    just my opinion

  3. Join Date
    Oct 2002
    Posts
    4,801
    #23
    marv, mbt hit the bullseye when he mentioned the gear ratio. See my previous post with quotation. I believe MBT's reply is in general, Honda, Mazda or Toyota.

    If only MZ3 has a better gearing or more gears while having a 150ft-lb torque, then the fuel consumption would have been better.

    i.e. 2005 Camry 2.4l A/T has an identical ratio of 0.756 compared to 2.3l MZ3 0.725. However, Camry has five gears compared to MZ3's four gears.

    Camry 24/34 vs Mazda3 2.3l 24/29

    Camry 2.4l has more gears thus the highway fuel consumption is better than the 2.3l Mazda3

    Related yata ang torque and gear ratio sa fuel consumption
    Last edited by Karding; July 12th, 2005 at 12:52 AM.

  4. Join Date
    Oct 2002
    Posts
    4,614
    #24
    marv,

    ah... hehe, i think i get what you're trying to drive at. so youre saying that perhaps an engine that produces peak torque at lower revs will be more efficient than an engine that produces a similar peak torque but at higher revs, because it (the latter) will need to be revved higher to accelerate? (tama ba, hehe?)

    mahirap din masabi hehe, because the two engines will have different fuel injector specifications (the amount of fuel injected into the cylinder per stroke), different gearing, etc... but you have a point in that an engine with good low-end torque will be able to get by with fewer revs in real-world (particularly city) driving compared to a similarly-sized engine that is peakier (although i don't think it will necessarily mean that the engine with better low-end torque will have better real-world fuel economy).

    pareng karding,

    langhya di naman ako expert ha :bwahaha: having more gears will generally improve highway fuel economy because it will allow a taller top gear. example, lets say a four-speed has the following ratios: 3.3, 2.0, 1.0, 0.7. they can't make the top gear extra-tall, like say, 0.5, because the difference from the previous gear will be too big (upshifts will drop revs too much, will affect drivability). but if they make it into a five-speed, they could, for example, use the following ratios: 3.3, 2.0, 1.0, 0.7, 0.5.

    but if the four-speed and the five-speed will have identical top gear ratios (ginawa lang mas closely-spaced yung ratios), for example, from 3.3, 2.0, 1.0, 0.7 to 3.3, 2.4, 1.3, 0.9, 0.7, there likely won't be a difference in cruising fuel economy. (this is with the same engine at yung number of tranny gears lang ang naiba)
    Last edited by mbt; July 12th, 2005 at 01:48 AM.

  5. #25
    Karding hows the fuel consumption of your Mazda 3?

  6. Join Date
    Dec 2004
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    430
    #26
    mbt tumpak hehehe

  7. Join Date
    Oct 2002
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    4,801
    #27
    Quote Originally Posted by ILuvDetailing
    Karding hows the fuel consumption of your Mazda 3?
    last measurement ko is 28mpg combined highway and city with occasional A/C. The more I go with the flow of highway traffic in California, the more fuel I consume. Typical speed on the highway is 75-80mph.

    My wife's 1.8 Sentra is rated 29/34 with A/T and mas mababa ang RPM compared to MZ3 when cruising at 75mph. Although, 128hp/130ft-lb lang yon.

  8. Join Date
    Dec 2004
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    430
    #28
    wats the conversion on km/liter karding ?

  9. Join Date
    Jun 2010
    Posts
    2
    #29
    Sorry to revive a very old thread - I am in need of a Mazda 3 2.0L engine to go in a 2007 car. I seem to have destroyed my own engine. Can anybody point me to the specs which distinguish between the different 2.0L engine types. I have seen references to VIN F and VIN G types on eBay but my VIN doesn't have an F or a G.

    Tnx

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Mazda 6 Engine = Mazda 3 2.0 engine?