13 ms·

Has the art of using the engine to slow down become so unknown that it is no longer considered a way to slow down a vehicle?

monochromatic 14y ago
It's not nearly as effective as braking.
- k00pa 14y ago
  I can drive without using brakes at all... And I do slow down. Brakes are when I need to slow down fast.
- X-Istence 14y ago
  In most cases though if you pay attention to the road and the conditions around you, engine braking can be used quite effectively, and it is not as jarring as braking using the brakes. This helps when you've got friends/family that easily get car sick, mainly due to the jerky motions from people hitting the gas too hard, and slamming on their brakes. I use my engine to brake about as much as I use my brakes. It provides for a smoother ride overall. That being said, engine braking tends to only work really well with stick shifts...
roel_v 14y ago
Only works on stick shifts.
- mpyne 14y ago
  It also works on automatics that can be command-shifted, which are becoming somewhat more common.
- TorKlingberg 14y ago
  Some automatic transmissions allow the driver to force a lower gear to engine break. It is not used as often, but can be useful in long slopes to avoid overheating the breaks and reduce wear.
  - roel_v 14y ago
    AFAIK mine does it automatically (i.e., when driving down a slope, it engine brakes to avoid acceleration). Then again we don't have that many slopes so maybe I misinterpreted what was happening the few times I drove down a parking garage :)
    - luser001 14y ago
      What car? Without cruise control? My car doesn't downshift unless I've set it on cruise control at an intermediate speed like 55 mph and it is a long downhill slope. I understand why: it's most efficient to drive in the highest gear even at speeds as low as 45 mph in a manual. I would imagine it's similar for automatics too.
      - roel_v 14y ago
        2006 BMW X3, yes without cruise control on. I'm not sure if it downshifts - what I meant was that the transmission adjusts itself to brake on the engine when coasting downhill, so that you don't have to brake in order to not accelerate downhill.
        OldSchool 14y ago
        Interesting, I first saw this automatic trans behavior as early as about Y2K in a midrange Mercedes but only with the cruise control on, and it did actually downshift to set up the engine braking effect. I've never encountered it with cruise control off though. Ford trucks with a Tow/Haul button enabled will do exactly what you describe though, especially if you tap the brake for an instant while going downhill.
        bradleyland 14y ago
        I can vouch for this; I think this is a BMW thing. Our 2012 X3 does the same thing. If you let off the gas while going down hill, you can see the RPMs on the tach rise as the transmission downshifts. I was really pleased with the feature on a trip to Asheville last fall.
    - deleted 14y ago
- monochromatic 14y ago
  Every automatic I've ever seen allows you to shift to a lower gear.
  - roel_v 14y ago
    Not unconditionally - yes you can switch to a 'manual' mode, but it won't let you e.g. shift to 1st gear when you're driving 100. The manual shifting is useful when driving on steep slopes, mostly. Furthermore, the gear selector certainly won't let you slip the clutch a little bit, like what you need for engine braking.
    - X-Istence 14y ago
      You shouldn't be slipping the clutch while engine braking. At that point you are simply moving the braking from the brake pads/rotors which are designed for it to the clutch disk/friction material... which is definitely not designed for it. Engine braking works well when you rev-match as you downshift, then when in the lower gear simply let off the gas completely. You will slow down, and at that point your drive/axle is pretty much directly connected to the engine which is simply turning without gas being injected into it, thus using the compression cycle to slow you down. In a manual car you don't want to shift to 1st gear when you are driving 100. That's bloody insane (Whether that is 100 km/h or 100 mph).
      - roel_v 14y ago
        You're driving 100, in 5th. You want to decelerate, so you press down the clutch, put the stick into 4th gear, then slowly release the clutch until you feel it gripping, and you do this until the rpms are low enough to switch to the 3rd in the same way. I don't know much about cars, but that process seems to be what you mean by 'rev matching'. While doing that, the clutch is slipping (even if just a bit), that's what I meant. I think you think I was saying that you switch to 1st and let the clutch come up until you stand still, but that's not what I meant.
        X-Istence 14y ago
- AUmrysh 14y ago
  My auto Mazda 3 has 'manumatic' shifting, and you can downshift to slow down in it. I guess it's not really the same though as the computer does a lot of shifting and timing for you even in manumatic mode.
  - woogley 14y ago
    I have this same car and exclusively use this technique in tunnel traffic. The computer has saved me a few times from accidentally shifting into 1st gear at 40mph ..
- sageikosa 14y ago
  Ford Freestyle with continuously variable transmission. Revs the engine way up on downhills.
- X-Istence 14y ago
  And every single last automatic. Besides D there is always a couple others, like 1, 2, 3 that are used for getting out of sticky situation or when you need a lot of torque... those also apply for engine braking. Do I suggest engine braking in an automatic in the general case? No, generally because the torque converter isn't too happy unless it was specifically designed for it. However if you are going down a steep mountain you better downshift even in an automatic and use the engine, or when you get to the bottom your rotors will be glowing red, your brake pads will be disintegrated, your brake fluid will be boiling and your car will be smelled from miles away. Yes, I have seen people brake all the way down the I-70 coming over the vail pass in Colorado, and it isn't pretty... if it doesn't break everything your rotors are going to be warped completely...
  - luser001 14y ago
    Kids, listen to this man. :) When I was newbie, I didn't downshift and was instead keeping the brakes lightly pressed. After a few mins of this, when I pressed them a little harder to slow down more (at a turn), the pedals sickeningly went way more than they were supposed to. Remembered in a flash what had happend. Thankfully, I was able to pull over and let the brakes cool a bit. The brake fluid had overheated and turned into a compressible liquid (if you remember your Pascal's Law (iirc), hydraulics can only work if the fluid is nearly incompressible).
    - X-Istence 14y ago
      Eh, I'm 24 years old ... in the crowd here on HN I would be considered part of that "kids" :P
hackmiester 14y ago
If this was written by an American, yes. I don't know many people who know what "engine braking" is. A very slightly higher number of people I know are capable of driving a standard shift vehicle. Most people know what a manual transmission is, but not everyone.
- ry0ohki 14y ago
  This was my first thought too. People use their brakes way too much (and usually because they drive automatic transmissions)
  - X-Istence 14y ago
    Each time you use the brakes, the energy has to be dissipated somehow, and that is done by heating up the brake pads and rotors. I know people that will use brakes the entire way down a mountain, even in a stick shift but even more so in an automatic... and then wonder why it smells like overheating brakes and why their rotors are glowing red. Then comes the weird feeling while braking because the rotors are warped...
- Isamu 14y ago
  The US is a big place. Those who live in mountain states certainly know to downshift rather than burn out their brakes.
  - hackmiester 14y ago
    I live in a state that has a few mountains (not a mountainous state, though). A lot of people I know just have shitty brakes now. I have no idea why knowledge of downshifting is not getting out. Even an automatic transmission will support it.
- eitland 14y ago
  We hardly have automatic transmissions in Scandinavia, in fact I had to explain it to my wife just the other day when she were using a rental car. Also you have to use manual in driving schools including at the exam or you will get a second class license that only counts for automatic cars.
jamesjguthrie 14y ago
It was completely frowned upon in my driving education (around 7 years ago) - and my driving school was/is the most popular in the UK. I always do a combination of down-shifting and braking as this saves fuel vs purely engine braking and I'm using my brakes what they were designed for; and you don't ever want to try emergency braking with cold brakes.
- k00pa 14y ago
  Something wrong with your driving education then...
  - prawks 14y ago
    It's pretty simple to see that traditional braking triggers brake lights, while engine braking does not. Brake lights are there for safely, to prevent rear-ends. I'd be shocked if any driving education program encouraged engine braking. On a slightly different note, if your rev-matching isn't smooth when you downshift to engine brake, you're just using your clutch to slow the car, which is a much more expensive part to replace than brake pads/rotors.
    - X-Istence 14y ago
      In most cases when it is appropriate to use engine braking the person behind you has to already start matching your speed. In situations where you have to brake suddenly and quickly brake lights can warn the other driver, but in most cases when you are downshifting to engine brake you are slowing down slowly enough that the person behind you can make proper adjustments simply based upon the fact that they are now getting closer to you. It's a human PID loop! As for rev matching, yes, completely agreed, if you can't rev match your down shifts then engine braking is indeed going to use your clutch and that is more expensive to replace. However, if you are driving a stick shift car and you don't know how to properly rev-match on downshifts how will you easily get up the mountain where shifting from fifth to fourth to third is sometimes required simply to keep up with traffic properly? I can go from fifth at 3k to fourth at 5k without issues. Rev-matching in a stick shift is very important outside of the engine braking use case.
lutusp 14y ago
> Has the art of using the engine to slow down become so unknown that it is no longer considered a way to slow down a vehicle? Most cars now have automatic transmissions, and in many such cars the habit of slowing down by downshifting will destroy the transmission's bands and wear down the rear differential, neither of which is designed for the stress caused by downshifting. I'm not speaking hypothetically -- I mostly drive manual transmissions and I'm accustomed to downshifting to slow down. I then acquired a car with an automatic transmission, but didn't change my behavior. Within 20,000 miles I had destroyed the transmission and the rear differential.

monochromatic 14y ago

It's not nearly as effective as braking.

k00pa 14y ago
I can drive without using brakes at all... And I do slow down. Brakes are when I need to slow down fast.
X-Istence 14y ago
In most cases though if you pay attention to the road and the conditions around you, engine braking can be used quite effectively, and it is not as jarring as braking using the brakes. This helps when you've got friends/family that easily get car sick, mainly due to the jerky motions from people hitting the gas too hard, and slamming on their brakes. I use my engine to brake about as much as I use my brakes. It provides for a smoother ride overall. That being said, engine braking tends to only work really well with stick shifts...

roel_v 14y ago

Only works on stick shifts.

mpyne 14y ago
It also works on automatics that can be command-shifted, which are becoming somewhat more common.
TorKlingberg 14y ago
Some automatic transmissions allow the driver to force a lower gear to engine break. It is not used as often, but can be useful in long slopes to avoid overheating the breaks and reduce wear.
- roel_v 14y ago
  AFAIK mine does it automatically (i.e., when driving down a slope, it engine brakes to avoid acceleration). Then again we don't have that many slopes so maybe I misinterpreted what was happening the few times I drove down a parking garage :)
  - luser001 14y ago
    What car? Without cruise control? My car doesn't downshift unless I've set it on cruise control at an intermediate speed like 55 mph and it is a long downhill slope. I understand why: it's most efficient to drive in the highest gear even at speeds as low as 45 mph in a manual. I would imagine it's similar for automatics too.
    - roel_v 14y ago
      2006 BMW X3, yes without cruise control on. I'm not sure if it downshifts - what I meant was that the transmission adjusts itself to brake on the engine when coasting downhill, so that you don't have to brake in order to not accelerate downhill.
      - OldSchool 14y ago
        Interesting, I first saw this automatic trans behavior as early as about Y2K in a midrange Mercedes but only with the cruise control on, and it did actually downshift to set up the engine braking effect. I've never encountered it with cruise control off though. Ford trucks with a Tow/Haul button enabled will do exactly what you describe though, especially if you tap the brake for an instant while going downhill.
      - bradleyland 14y ago
        I can vouch for this; I think this is a BMW thing. Our 2012 X3 does the same thing. If you let off the gas while going down hill, you can see the RPMs on the tach rise as the transmission downshifts. I was really pleased with the feature on a trip to Asheville last fall.
  - deleted 14y ago
monochromatic 14y ago
Every automatic I've ever seen allows you to shift to a lower gear.
- roel_v 14y ago
  Not unconditionally - yes you can switch to a 'manual' mode, but it won't let you e.g. shift to 1st gear when you're driving 100. The manual shifting is useful when driving on steep slopes, mostly. Furthermore, the gear selector certainly won't let you slip the clutch a little bit, like what you need for engine braking.
  - X-Istence 14y ago
    You shouldn't be slipping the clutch while engine braking. At that point you are simply moving the braking from the brake pads/rotors which are designed for it to the clutch disk/friction material... which is definitely not designed for it. Engine braking works well when you rev-match as you downshift, then when in the lower gear simply let off the gas completely. You will slow down, and at that point your drive/axle is pretty much directly connected to the engine which is simply turning without gas being injected into it, thus using the compression cycle to slow you down. In a manual car you don't want to shift to 1st gear when you are driving 100. That's bloody insane (Whether that is 100 km/h or 100 mph).
    - roel_v 14y ago
      You're driving 100, in 5th. You want to decelerate, so you press down the clutch, put the stick into 4th gear, then slowly release the clutch until you feel it gripping, and you do this until the rpms are low enough to switch to the 3rd in the same way. I don't know much about cars, but that process seems to be what you mean by 'rev matching'. While doing that, the clutch is slipping (even if just a bit), that's what I meant. I think you think I was saying that you switch to 1st and let the clutch come up until you stand still, but that's not what I meant.
      - X-Istence 14y ago
AUmrysh 14y ago
My auto Mazda 3 has 'manumatic' shifting, and you can downshift to slow down in it. I guess it's not really the same though as the computer does a lot of shifting and timing for you even in manumatic mode.
- woogley 14y ago
  I have this same car and exclusively use this technique in tunnel traffic. The computer has saved me a few times from accidentally shifting into 1st gear at 40mph ..
sageikosa 14y ago
Ford Freestyle with continuously variable transmission. Revs the engine way up on downhills.
X-Istence 14y ago
And every single last automatic. Besides D there is always a couple others, like 1, 2, 3 that are used for getting out of sticky situation or when you need a lot of torque... those also apply for engine braking. Do I suggest engine braking in an automatic in the general case? No, generally because the torque converter isn't too happy unless it was specifically designed for it. However if you are going down a steep mountain you better downshift even in an automatic and use the engine, or when you get to the bottom your rotors will be glowing red, your brake pads will be disintegrated, your brake fluid will be boiling and your car will be smelled from miles away. Yes, I have seen people brake all the way down the I-70 coming over the vail pass in Colorado, and it isn't pretty... if it doesn't break everything your rotors are going to be warped completely...
- luser001 14y ago
  Kids, listen to this man. :) When I was newbie, I didn't downshift and was instead keeping the brakes lightly pressed. After a few mins of this, when I pressed them a little harder to slow down more (at a turn), the pedals sickeningly went way more than they were supposed to. Remembered in a flash what had happend. Thankfully, I was able to pull over and let the brakes cool a bit. The brake fluid had overheated and turned into a compressible liquid (if you remember your Pascal's Law (iirc), hydraulics can only work if the fluid is nearly incompressible).
  - X-Istence 14y ago
    Eh, I'm 24 years old ... in the crowd here on HN I would be considered part of that "kids" :P

hackmiester 14y ago

If this was written by an American, yes. I don't know many people who know what "engine braking" is. A very slightly higher number of people I know are capable of driving a standard shift vehicle. Most people know what a manual transmission is, but not everyone.

ry0ohki 14y ago
This was my first thought too. People use their brakes way too much (and usually because they drive automatic transmissions)
- X-Istence 14y ago
  Each time you use the brakes, the energy has to be dissipated somehow, and that is done by heating up the brake pads and rotors. I know people that will use brakes the entire way down a mountain, even in a stick shift but even more so in an automatic... and then wonder why it smells like overheating brakes and why their rotors are glowing red. Then comes the weird feeling while braking because the rotors are warped...
Isamu 14y ago
The US is a big place. Those who live in mountain states certainly know to downshift rather than burn out their brakes.
- hackmiester 14y ago
  I live in a state that has a few mountains (not a mountainous state, though). A lot of people I know just have shitty brakes now. I have no idea why knowledge of downshifting is not getting out. Even an automatic transmission will support it.
eitland 14y ago
We hardly have automatic transmissions in Scandinavia, in fact I had to explain it to my wife just the other day when she were using a rental car. Also you have to use manual in driving schools including at the exam or you will get a second class license that only counts for automatic cars.

jamesjguthrie 14y ago

It was completely frowned upon in my driving education (around 7 years ago) - and my driving school was/is the most popular in the UK. I always do a combination of down-shifting and braking as this saves fuel vs purely engine braking and I'm using my brakes what they were designed for; and you don't ever want to try emergency braking with cold brakes.

k00pa 14y ago
Something wrong with your driving education then...
- prawks 14y ago
  It's pretty simple to see that traditional braking triggers brake lights, while engine braking does not. Brake lights are there for safely, to prevent rear-ends. I'd be shocked if any driving education program encouraged engine braking. On a slightly different note, if your rev-matching isn't smooth when you downshift to engine brake, you're just using your clutch to slow the car, which is a much more expensive part to replace than brake pads/rotors.
  - X-Istence 14y ago
    In most cases when it is appropriate to use engine braking the person behind you has to already start matching your speed. In situations where you have to brake suddenly and quickly brake lights can warn the other driver, but in most cases when you are downshifting to engine brake you are slowing down slowly enough that the person behind you can make proper adjustments simply based upon the fact that they are now getting closer to you. It's a human PID loop! As for rev matching, yes, completely agreed, if you can't rev match your down shifts then engine braking is indeed going to use your clutch and that is more expensive to replace. However, if you are driving a stick shift car and you don't know how to properly rev-match on downshifts how will you easily get up the mountain where shifting from fifth to fourth to third is sometimes required simply to keep up with traffic properly? I can go from fifth at 3k to fourth at 5k without issues. Rev-matching in a stick shift is very important outside of the engine braking use case.

lutusp 14y ago

> Has the art of using the engine to slow down become so unknown that it is no longer considered a way to slow down a vehicle? Most cars now have automatic transmissions, and in many such cars the habit of slowing down by downshifting will destroy the transmission's bands and wear down the rear differential, neither of which is designed for the stress caused by downshifting. I'm not speaking hypothetically -- I mostly drive manual transmissions and I'm accustomed to downshifting to slow down. I then acquired a car with an automatic transmission, but didn't change my behavior. Within 20,000 miles I had destroyed the transmission and the rear differential.