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> when automatic transmissions are consistently > outperforming humans at fuel efficiency What? So far each data sheet has shown higher fuel consumption for

> when automatic transmissions are consistently > outperforming humans at fuel efficiency What? So far each data sheet has shown higher fuel consumption for automatic vehicles.

trynumber9 10y ago
DCTs are typically 3–5% more fuel-efficient than manual transmissions.
- pedrocr 10y ago
  That's to be expected as a dual-clutch transmission is a robotically operated manual transmission with an extra degree of freedom. Most automatics are completely different technology that has always been less efficient.
silon7 10y ago
It's only correct for modern automatic transmissions. Plus sometimes start/stop. Probably not for old "3 gear with torque converter" or similiar.
- Reason077 10y ago
  Modern manual cars have start/stop technology too. However, it's more convoluted to use. You have to engage the clutch, put the shifter in neutral, and release the clutch again. Compared to automatic where you just have to hold your foot on the brake pedal. Stop/start reduces fuel consumption on test cycles like NEDC for both automatics and manuals, but I'll bet in the real world the benefit is mostly seen with automatics as many manual drivers will rarely bother to use it.
  - kifki 10y ago
    Manual car with start&stop owner here; I always use it when driving in the city, so do all of my friends. It's just slightly uncomfortable the first times, when you have to train your muscle memory.
  - edoloughlin 10y ago
    However, it's more convoluted to use. You have to engage the clutch, put the shifter in neutral, and release the clutch again This is how you should drive if you know you're going to be stopped for more than a few seconds. 'Convoluted' doesn't come into it - it's the default.
    - dogma1138 10y ago
      I want to see the people who cycle the clutch twice at a red signal.
      - Ntrails 10y ago
        When stopped you have two options in a car, sitting with your foot on the clutch (which is flat out bad) and putting the car in neutral. Putting the car in neutral is basically one meaningful action - changing gear, yes you have to depress the clutch move the gearstick to neutral and then let the clutch go - but to describe that as "cycle the clutch twice" is madness. Am I missing something?
        Dylan16807 10y ago
        You have to take it back out of neutral, making two cycles of the clutch. No madness involved.
      - mnw21cam 10y ago
        Most people in the UK? At least, if they want to pass their driving test.
      - usrusr 10y ago
        What else is there to do? I don't text in the driver's seat, putting the gear in neutral gives my limbs something to do. (It happens to involve the clutch, but that is "automatic", as in "muscle memory", even though I drive less than once a month)
      - apetrovic 10y ago
        If I'm expecting to stop more than few seconds, I put my car in neutral. Every time. For last, let's see, 28 years since I have my driving license.
  - rlpb 10y ago
    > You have to engage the clutch, put the shifter in neutral, and release the clutch again. That's both a long-winded and incorrect way of putting it. If you are stopped, then you're either already in neutral with the clutch released or the clutch is already engaged. There is no other way. Really, the rule is just "you have to have the clutch released". For experienced drivers of manual transmissions, this is one smooth action.
  - beefield 10y ago
    > Stop/start reduces fuel consumption on test cycles like NEDC I would like to know: 1. How long you need to idle to recharge the electricity to battery you use to restart the engine? 2. Does NEDC and others require that the battery has same state of charge at the end of the cycle as when beginning?
    - Reason077 10y ago
      Not really an issue. The energy used to restart the engine is small compared to the fuel savings. An electric starter motor is very efficient compared to a combustion engine at idle. Stop/start will automatically disable if the battery has a low state of charge.
  - aluhut 10y ago
    Just have to hold your food on the brake? It's a pain...and depending on the break, it really may become pain. Usually if I drive my manual private car, I disengage the gear already on the way to the red light. It just rolls. I break, motor turns off. When I want to start, I push the clutch, motor turns on, off you go. The good thing is, If I want the motor to launch, I can by pushing the clutch slightly. I can also release it and put my legs wherever I want. I can relax. Holding one leg constantly on the break is just annoying. For you, your leg and the guy behind you who has to look into that bright red light pointlessly shining in his eyes.
    - Reason077 10y ago
      Just have to hold your food on the brake? It's a pain...and depending on the break, it really may become pain. Oh, with an automatic you have the option of putting it in Park also. Certainly, it's a good idea to do that if you're stopped for more than a few seconds. You don't have to keep your foot on the brake, but doing so is enough to activate stop/start.
henrikschroder 10y ago
I should probably have qualified my statement with an "over time, in real driving conditions". In a measured test, with a skilled driver, who does the right thing for the entirety of the test, it is most likely that he or she will be more efficient with a manual transmission than with an automatic. However, in real life, for real humans, over a longer period of time, the drivers with modern automatic transmissions will be more fuel efficient than drivers with similar cars and manual transmissions, because the automatic transmission is a reliable machine that will do the same thing, every time. It doesn't care if you had your morning coffee or not, if some asshole cut you off, or if you got distracted or bored or spaced out and forgot to change your gear to the right one. And, disregarding the disruption the EVs will be, technology constantly improves, while human skill is fairly constant, so it was just inevitable that automatic transmissions would one day overtake manual transmissions in terms of speed and efficiency. Arguing otherwise is just irrational nostalgia.
- deleted 10y ago
  [deleted]
- kalleboo 10y ago
  I'd love to see some kind of study that went deep into how the results pan out over a certain population and why. My own anecdote is that I'm a better driver in a manual. I'm a lazy driver, and lazy in a manual means avoiding stopping/gear changes by anticipating green lights and so on. Being lazy in an automatic results in more stop and go for me because it's no more effort. I could be as efficient in an automatic, if I put in the effort (which I would probably do if I knew my numbers were going into a study).
  - henrikschroder 10y ago
    Many modern cars are completely drive-by-wire, and have a mode selector inbetween your controls and the car, which forces you into more fuel-efficient driving, e.g. ignoring if you push the speeder all the way down, and accelerating the car at an efficient pace instead. The more sensors and processing you get in a car, the better the car can be a this. Other modern cars have an "eco display" or similar, which gamifies the experience. My previous car had some progress bars for different aspects, and I spent several boring commutes trying to get to a perfect 100%. (I did it once, I was so happy! Usually only got it to 98% before I hit the city and got stuck in traffic again) Making automatics more efficient is a technological optimization problem. Making manuals more efficient is a human skill problem. I know which side I'd bet on in the long run. (Hint: Not the human)
Tomte 10y ago
Sure, for professional racing drivers. The vast majority, certainly >90%, of people who claim to be driving more efficiently manually are simply mistaken. It's mostly observation bias. They recognize those two situations a day where they really have the upper hand. For a second or two. They don't realize that in most other driving situations they don't even come close.
- amelius 10y ago
  > Sure, for professional racing drivers. But note that the transmission in F1 cars is semi-automatic [1] [1] https://www.formula1.com/en/championship/inside-f1/understanding-f1-racing/power-unit---gearbox.html https://www.formula1.com/en/championship/inside-f1/understan...
  - userbinator 10y ago
    The only "automatic" part of that transmission is the clutch. The driver still has to select the gear, and I think that's what the whole discussion here about manual vs. automatic is focusing on.
    - monk_e_boy 10y ago
      They drive to the beeps, so the computer is beeping in their ear when it is time to change. And they don't shift through neutral to select a gear. They may as well be automatic for all the input an F1 driver has
      - rlau26 10y ago
        The computer beeping is merely a reminder and I'm betting most drivers will even disregard it after they are familiar with the track they are on. Gear changes happen so often and so quickly that waiting for a computer to tell you when to shift is a sure sign of unfamiliarity with the track layout and it's also a hit to one's concentration (ex. if they're trying to pass the car ahead or block the one behind). Anyone that does any sort of track driving consistently should know what gear their car should be in for each corner long before a race.
vmasto 10y ago
Source please?
kyrra 10y ago
False. Maybe that used to be true, but it's been shifting. Automatics are more efficient than manuals. Examples: https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=7&year=2016&make=Honda&model=Accord&srchtyp=ymm https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform... https://www.fueleconomy.gov/feg/bymodel/2016_Mazda_6.shtml https://www.fueleconomy.gov/feg/bymodel/2016_Mazda_6.shtml

> when automatic transmissions are consistently > outperforming humans at fuel efficiency What? So far each data sheet has shown higher fuel consumption for automatic vehicles.

trynumber9 10y ago

DCTs are typically 3–5% more fuel-efficient than manual transmissions.

pedrocr 10y ago
That's to be expected as a dual-clutch transmission is a robotically operated manual transmission with an extra degree of freedom. Most automatics are completely different technology that has always been less efficient.

silon7 10y ago

It's only correct for modern automatic transmissions. Plus sometimes start/stop. Probably not for old "3 gear with torque converter" or similiar.

Reason077 10y ago
Modern manual cars have start/stop technology too. However, it's more convoluted to use. You have to engage the clutch, put the shifter in neutral, and release the clutch again. Compared to automatic where you just have to hold your foot on the brake pedal. Stop/start reduces fuel consumption on test cycles like NEDC for both automatics and manuals, but I'll bet in the real world the benefit is mostly seen with automatics as many manual drivers will rarely bother to use it.
- kifki 10y ago
  Manual car with start&stop owner here; I always use it when driving in the city, so do all of my friends. It's just slightly uncomfortable the first times, when you have to train your muscle memory.
- edoloughlin 10y ago
  However, it's more convoluted to use. You have to engage the clutch, put the shifter in neutral, and release the clutch again This is how you should drive if you know you're going to be stopped for more than a few seconds. 'Convoluted' doesn't come into it - it's the default.
  - dogma1138 10y ago
    I want to see the people who cycle the clutch twice at a red signal.
    - Ntrails 10y ago
      When stopped you have two options in a car, sitting with your foot on the clutch (which is flat out bad) and putting the car in neutral. Putting the car in neutral is basically one meaningful action - changing gear, yes you have to depress the clutch move the gearstick to neutral and then let the clutch go - but to describe that as "cycle the clutch twice" is madness. Am I missing something?
      - Dylan16807 10y ago
        You have to take it back out of neutral, making two cycles of the clutch. No madness involved.
    - mnw21cam 10y ago
      Most people in the UK? At least, if they want to pass their driving test.
    - usrusr 10y ago
      What else is there to do? I don't text in the driver's seat, putting the gear in neutral gives my limbs something to do. (It happens to involve the clutch, but that is "automatic", as in "muscle memory", even though I drive less than once a month)
    - apetrovic 10y ago
      If I'm expecting to stop more than few seconds, I put my car in neutral. Every time. For last, let's see, 28 years since I have my driving license.
- rlpb 10y ago
  > You have to engage the clutch, put the shifter in neutral, and release the clutch again. That's both a long-winded and incorrect way of putting it. If you are stopped, then you're either already in neutral with the clutch released or the clutch is already engaged. There is no other way. Really, the rule is just "you have to have the clutch released". For experienced drivers of manual transmissions, this is one smooth action.
- beefield 10y ago
  > Stop/start reduces fuel consumption on test cycles like NEDC I would like to know: 1. How long you need to idle to recharge the electricity to battery you use to restart the engine? 2. Does NEDC and others require that the battery has same state of charge at the end of the cycle as when beginning?
  - Reason077 10y ago
    Not really an issue. The energy used to restart the engine is small compared to the fuel savings. An electric starter motor is very efficient compared to a combustion engine at idle. Stop/start will automatically disable if the battery has a low state of charge.
- aluhut 10y ago
  Just have to hold your food on the brake? It's a pain...and depending on the break, it really may become pain. Usually if I drive my manual private car, I disengage the gear already on the way to the red light. It just rolls. I break, motor turns off. When I want to start, I push the clutch, motor turns on, off you go. The good thing is, If I want the motor to launch, I can by pushing the clutch slightly. I can also release it and put my legs wherever I want. I can relax. Holding one leg constantly on the break is just annoying. For you, your leg and the guy behind you who has to look into that bright red light pointlessly shining in his eyes.
  - Reason077 10y ago
    Just have to hold your food on the brake? It's a pain...and depending on the break, it really may become pain. Oh, with an automatic you have the option of putting it in Park also. Certainly, it's a good idea to do that if you're stopped for more than a few seconds. You don't have to keep your foot on the brake, but doing so is enough to activate stop/start.

henrikschroder 10y ago

I should probably have qualified my statement with an "over time, in real driving conditions". In a measured test, with a skilled driver, who does the right thing for the entirety of the test, it is most likely that he or she will be more efficient with a manual transmission than with an automatic. However, in real life, for real humans, over a longer period of time, the drivers with modern automatic transmissions will be more fuel efficient than drivers with similar cars and manual transmissions, because the automatic transmission is a reliable machine that will do the same thing, every time. It doesn't care if you had your morning coffee or not, if some asshole cut you off, or if you got distracted or bored or spaced out and forgot to change your gear to the right one. And, disregarding the disruption the EVs will be, technology constantly improves, while human skill is fairly constant, so it was just inevitable that automatic transmissions would one day overtake manual transmissions in terms of speed and efficiency. Arguing otherwise is just irrational nostalgia.

deleted 10y ago
[deleted]
kalleboo 10y ago
I'd love to see some kind of study that went deep into how the results pan out over a certain population and why. My own anecdote is that I'm a better driver in a manual. I'm a lazy driver, and lazy in a manual means avoiding stopping/gear changes by anticipating green lights and so on. Being lazy in an automatic results in more stop and go for me because it's no more effort. I could be as efficient in an automatic, if I put in the effort (which I would probably do if I knew my numbers were going into a study).
- henrikschroder 10y ago
  Many modern cars are completely drive-by-wire, and have a mode selector inbetween your controls and the car, which forces you into more fuel-efficient driving, e.g. ignoring if you push the speeder all the way down, and accelerating the car at an efficient pace instead. The more sensors and processing you get in a car, the better the car can be a this. Other modern cars have an "eco display" or similar, which gamifies the experience. My previous car had some progress bars for different aspects, and I spent several boring commutes trying to get to a perfect 100%. (I did it once, I was so happy! Usually only got it to 98% before I hit the city and got stuck in traffic again) Making automatics more efficient is a technological optimization problem. Making manuals more efficient is a human skill problem. I know which side I'd bet on in the long run. (Hint: Not the human)

Tomte 10y ago

Sure, for professional racing drivers. The vast majority, certainly >90%, of people who claim to be driving more efficiently manually are simply mistaken. It's mostly observation bias. They recognize those two situations a day where they really have the upper hand. For a second or two. They don't realize that in most other driving situations they don't even come close.

amelius 10y ago
> Sure, for professional racing drivers. But note that the transmission in F1 cars is semi-automatic [1] [1] https://www.formula1.com/en/championship/inside-f1/understanding-f1-racing/power-unit---gearbox.html https://www.formula1.com/en/championship/inside-f1/understan...
- userbinator 10y ago
  The only "automatic" part of that transmission is the clutch. The driver still has to select the gear, and I think that's what the whole discussion here about manual vs. automatic is focusing on.
  - monk_e_boy 10y ago
    They drive to the beeps, so the computer is beeping in their ear when it is time to change. And they don't shift through neutral to select a gear. They may as well be automatic for all the input an F1 driver has
    - rlau26 10y ago
      The computer beeping is merely a reminder and I'm betting most drivers will even disregard it after they are familiar with the track they are on. Gear changes happen so often and so quickly that waiting for a computer to tell you when to shift is a sure sign of unfamiliarity with the track layout and it's also a hit to one's concentration (ex. if they're trying to pass the car ahead or block the one behind). Anyone that does any sort of track driving consistently should know what gear their car should be in for each corner long before a race.

vmasto 10y ago

Source please?

kyrra 10y ago

False. Maybe that used to be true, but it's been shifting. Automatics are more efficient than manuals. Examples: https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=7&year=2016&make=Honda&model=Accord&srchtyp=ymm https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform... https://www.fueleconomy.gov/feg/bymodel/2016_Mazda_6.shtml https://www.fueleconomy.gov/feg/bymodel/2016_Mazda_6.shtml