[Auto Talk] Can regularly shifting to Neutral on an automatic gear damage it?

Discussion in 'Lounge' started by Adrian Wong, May 14, 2008.

  1. mikegas

    mikegas Newbie

    1 person likes this.
  2. Mac Daddy

    Mac Daddy Pickin' Da Gitfiddle

  3. rogue_tomato

    rogue_tomato Newbie

  4. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Ahh.. the tailgate tip is correct. Most people assume that having the tailgate up will impede airflow and increase fuel consumption.

    I also use less-viscous engine oil, switching from 5W-50 to 10W-30. That did give me a noticeable improvement in fuel consumption.

    Hmm.. Must remember to pump petrol when it's cooler... Hehe... That's a useful tip. :thumb:

    Too bad it didn't mention anything about shifting in and out of neutral while the car's moving. Hehe.. Nice find though, mikegas! +rep! :thumb:
  5. Chai

    Chai Administrator Staff Member

    Because it's not a good way to save fuel!
  6. plasma

    plasma Newbie

    Haven't been here for quite some time but here's my take on the issue.

    Here are the typical recommendations and my thoughts on them.

    1. Keep in D while coasting downhill (or use low gear)
    - Depending on the incline, your engine may rev up.
    - I think this serves as a safety guide more than a fuel saving tip.
    - It's important to note that there is a minimal amount of fuel required to achieve a said RPM. If it goes above 2k, I'm pretty darn sure you're using more fuel than going into N.
    - I rather have wear and tear on my brake pads than on the engine by doing engine braking

    2. Don't shift to N at traffic lights, keep in D.
    - I don't wanna accidentally release my brake and scratch the guy in front
    - I know that having the torque converter on means I'm increasing wear and tear on both the brakes and the clutch plate.

    3. Don't shift to N when slowing down, keep it in D. Shifting back and forth between D and N will increase clutch plate wear
    - If you're braking with D engaged, you'll be wearing out the clutch anyway - in fact continuously.
    - Some say that engine braking (by keeping in D) will help reduce brake pad wear - again, I rather have wear & tear on my brake pads, thank you.
    - The auto-transmission shift gears down sequentially as you slow down anyway, clutch is automatically disengaged and engaged.
    - I'm not driving a too old car, I don't have to worry about the auto-transmission hunting gears when I shift to D before coming to a complete halt.

    In conclusion, I shift back and forth between D and N. I think shifters are called that for a reason, they're made to shift. If my manual shifter can last a lifetime of shifting, I bet the auto one can too.
    I handle my car well enough to not have to rely on safety measures that use more fuel.
  7. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Keeping the auto transmission in D will definitely rev up the engine. Instead of idling at around 900 RPM, my car's engine idles at around 1600 RPM going down hill when engaged in drive mode.

    Of course, there's also the problem of the engine automatically braking the car as it goes downhill. Instead of coasting and even accelerating downhill, I have to step on the pedal to keep the speed up.

    I'm confused about no. 2 though. Why not shift to N at the traffic lights. If you do, you won't have to worry about hitting the guy in front.

    Hmm.. As for no. 3, the auto transmission actually uses a torque converter, right? So, being continuously engaged should not wear it down. But if that's true, then disengaging and engaging it again and again should also not wear it down. I'm confused! :haha: :haha:
  8. Chai

    Chai Administrator Staff Member

    Looks like you never have auto box breaking down on you before. I've seen and driven a few cars till the auto-box have to be replaced. Good luck. :p

    Engine braking wears engine? What exactly does it wear? :p Engine probably last far longer than any other parts of the car including gearbox, brakes, clutch etc. Do you know that when the transmission is not engaged to the engine, it's easier to lose control of your car, not even constant braking will save you, unless you are travelling very slow. There's a reason why road signs warn you to use low gear when going down hill.

    The thing that worries me is, most auto-box tend to give problems after 10 years. But manual gearbox is still perfectly fine, and in most cases, last longer than engine, but I most probably changed to a newer car by then. :lol:
    Last edited: May 23, 2008
  9. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Wah... What cars were those? And how much did it cost you?

    Hmm.. My biggest worry going downhill for extended periods of time (like in Genting) is the brakes overheating and becoming useless.
  10. NeoSquall

    NeoSquall Newbie

    always go down hill in gear.. let the help you brake.. haha.. safety feature.. so that ur brakes wont overheat.. its not sexy to have your brakes overheating.. its very very very scary... happened to me after a spirited run downhill.. braking distance doubled..

    actually... is it true that when your foot is off the throttle and you are in gear going downhill and your car revs more than 3k RPM you are consuming more fuel compared to idling at low RPM? think about it.. your foot is off the throttle.. butterfly valve is closed.. little air is going thru your MAP sensor(if you have TPS.. then the butterfly valve will inform the ECU).. thus making the ECU think that you are in idle mode.. which means its the same as putting it to N..

    sensible? if more fuel is going in.. dont you think you will go downhill faster because its the same as you stepping down on the throttle..?

    man.. Im bad in explaning.. :wall: :wall: :wall: haha.. hope you guys understand..
  11. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Okay, so even if the engine revs go up while you are going downhill (without stepping on the pedal), it's actually idling and virtually in neutral? :think:

    Well, the pistons are still pumping. I'm just not sure if they are pumping air or actual combustion is taking place.
  12. Chai

    Chai Administrator Staff Member

    Personally driven Proton Saga, old Camry.
  13. Chai

    Chai Administrator Staff Member


    RPM and fuel consumption are not directly connected. If your foot is off the pedal, the engine is not using more petrol than at idle, that's why the engine is slowing down. It shouldn't use more fuel when you are in gear going down hill, unless you are on the pedal.
  14. wiiz

    wiiz Just Started

  15. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Hmm.. I see. So I guess the increased FC comes from having to press the pedal (due to loss of speed from engine braking).
  16. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Hmm.. Their explanations sound a bit iffy. Besides, I thought the engineers would have developed the most optimal operating settings for the engine. Seems a little unlikely for a few guys to improve on that. :think:
  17. wiiz

    wiiz Just Started

    yeah..that's why we need u to try 1st.:haha:
    anyway, they claimed that the program was developed by hyundai racing team, and they fine tuned some parameters to suite our fuel/wheather conditions (or something like that :mrgreen: ).
  18. Adrian Wong

    Adrian Wong Da Boss Staff Member

    ROTFL!!! So my car's the guinea pig la.. :haha: :haha:

    But frankly, for such software modding, it's really expensive. What I spend on it, I could just use it to pay for petrol. :haha: :haha:

    It doesn't reduce fuel consumption btw, just increases power and torque. Even so, I wonder if it's even possible to boost power and torque by so much in naturally-aspirated engines without the use of turbocharger.
  19. mikegas

    mikegas Newbie

    YES, NA car still can be modded to increase power and torque. There are stuff like race chip, more induce air intake and out.. etc. You can even put in an engine management unit which can be hook up to computer to tune. These are very popular with car modder esp playing vtec, mivec and such. I got a mechanic fren who does this for living, if you wish I can intro you.

    Of course, car modder would not bother much about fuel consumption, always more power. A trade between the two, power or economical plus comfort or performance.

    A good example of car is the Honda City VTEC and IDSI. The price of the Honda City VTEC is extra RM 5K. The performance is maybe extra 30hp. However, the IDSI is winner in economical, as a full tank of that car can go extra 100km than that of VTEC. I got the VTEC version cause want performance...
  20. Chai

    Chai Administrator Staff Member

    I don't think the difference is as much as 30bhp.

    Piggyback controller costs about RM1k+, it will not save petrol definitely.

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