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View Poll Results: Does a non-moving A/T car consume more fuel if the shifter is in D or N ??

Voters
65. You may not vote on this poll
  • consumes more fuel in D

    44 67.69%
  • consumes more fuel in N

    0 0%
  • I don't know.

    17 26.15%
  • I would like a faux sunroof for my car.

    4 6.15%
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Results 1 to 10 of 44
  1. Join Date
    Oct 2002
    Posts
    29,320
    #1
    Does a non-moving A/T car consume more fuel if the shifter is in D or N ??

    Imagine the situation is you are waiting for the traffic light to change from red to green.
    Last edited by ghosthunter; September 21st, 2007 at 11:33 AM.

  2. #2
    D consumes more kasi engaged ang tranny and braking it counter-acts the action of the tranny--kaya nga bumabagsak yung idle speed ng engine...

    N- is just in neutral--free moving ang a/t...

    eto pagkakaintindi ko..

  3. Join Date
    Mar 2004
    Posts
    2,053
    #3
    How about for short stops (e.g. less than 1 minute)?
    Will transitioning from D-to-N then N-to-D for short stops consume more fuel than just sticking to D?

  4. Join Date
    Nov 2005
    Posts
    1,985
    #4
    Whatever fuel you conserve won't be worth the cost of a new tranny caused by the wear and tear you cause from shifting back and forth for short stops. The rpm variation between D and N is really negligible to matter, you'd save more fuel by driving smart.

  5. #5
    kung madali lang ang traffic light, say less than 30 secs--leave to d lang..pero kung jam na iba na usapan yan...

    ang mahirap is ung filipino-traffic situation called: tutukan--where in ayaw mo pasingit sa mga pilit na sumisingit..

  6. Join Date
    Nov 2005
    Posts
    7,717
    #6
    D is my vote. not only gas consumption but also brakes and battery.

  7. Join Date
    Sep 2006
    Posts
    593
    #7
    kung quick stops lang, say a minute or less, ok lang iwan sa D. Pero kung matagal na stops, i think its better to put it in P.

    Not sure how true it is but I read somewhere that leaving an AT tranny in the N position for extended periods will starve the tranny of ATF.

  8. Join Date
    Apr 2007
    Posts
    2,283
    #8
    I would be more concerned about the stress you put on a transmission by leaving it in "D" position in a traffic jam, because it is engaged in "D" and it is suppose to be moving, IMO, it is better to shift to "N" when the car is in standby mode.

  9. Join Date
    Oct 2002
    Posts
    15,525
    #9
    Quote Originally Posted by ronw123w124 View Post
    I would be more concerned about the stress you put on a transmission by leaving it in "D" position in a traffic jam, because it is engaged in "D" and it is suppose to be moving, IMO, it is better to shift to "N" when the car is in standby mode.
    +1 here. even though the stops are quite low like let's say, 30 seconds, it is still moving, so the load is on the transmission as well as on the brakes.

    it is better if even in short stops, that you put it in neutral. you save gas, you save your brakes, you save your transmission. and besides, i think modern AT assemblies are very durable to do that.all it takes is one click of your hand.

  10. Join Date
    Aug 2004
    Posts
    22,710
    #10
    Why will putting it in "N" starve it or destroy it? The internal oil pump is continuously active as long as the engine is on. Whether or not there's any load on the torque converter, the internal fans are still spinning, so it's still being lubricated continuously.

    Putting it into neutral then into drive at idle does not damage anything, as the clutches are stopping a light disc spinning at merely 800 rpm.

    There is much more stress and heat on the whole torque converter assembly when accelerating before the converter locks-up (at somewhere between 2000-3500 rpm, depending on the car) than there is in shifting to Neutral at the stoplight.

    You can feel this on some high-powered engines... the stress on torque converters during pre-lock-up acceleration is really high, and you can feel the heat coming off the transmission housing by your leg. That's why most stock converters are built to lock-up at low rpms, to minimize the amount of time during which the two ends are spinning at different speeds.

    When you put it in "D" at the lights, you connect one end of torque converter to the drivetrain. So one end is spinning at 800-900 rpms, the other is locked to your drivetrain, which is locked in place by your brakes. This generates load, which uses up fuel... and it also generates heat. Tons of heat if you're sitting at a light for more than half-a-minute.

    This heat leads to the premature breakdown of your transmission fluid, which will harm your torque converter, which will lead to an awful overhaul bill in the future.

    And an awful amount of burned brake pads in the short-term, too.

    So... if the manufacturers want to limit the time that the torque converter spends unlocked and under load... shouldn't you, too? ;)
    Last edited by niky; September 21st, 2007 at 03:00 PM.

    Ang pagbalik ng comeback...

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