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Old 16th September 2011, 09:56   #211
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by simplyself View Post
Actually, touching the brake while slowing down is not bad altogether. It facilitates quicker down shifting. What many auto mags say is pointless. Engine braking is a measure of slowing down if the warning is very adavnced, I mean, if we detect something ahead very early then we can use engine braking. But I prefer getting into neutral immediately if I detect something ahead-e.g. take a speed breaker on a road - as it is immobile, I come into neutral and coast along for, say, about 20 metres, and by the time the rear tyres come off the breaker, I would rather be into appropriate gear. This is method I prefer.

The driver may be unaware of how the ABS works. The owner should have trained the driver properly. You cannot place blame squarely on the hapless driver who may not have driven a vehicle with ABS earlier.


This method is followed by several people on the road, but it is not advised.

Coasting in neutral is a bad idea. Let me help with a few points:

- Being in neutral and coasting consumes more fuel than it would if it were in gear. The reason being that the RPM will settle into a speed that spins the engine faster. In neutral, the engine spins faster than if you're in gear and slowing down.

- Reacting to something (like the necessity to brake and drive off quickly, suddenly) will be very hard if one is in neutral and coasting.

Engine braking is the best way to slow down while approaching a traffic-signal or an intersection from a distance. One must never:

- Put it in neutral and coast along and dab the brakes gently.

- Keep the clutch completely depressed and dab the brakes and come to a halt gradually.

Google this topic for more info. Team BHP also has a thread dedicated to the same. Do read up about it and understand the issues regarding the same.

Last edited by suhaas307 : 16th September 2011 at 09:58.
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Old 16th September 2011, 10:04   #212
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by VeluM View Post
In short, in emergencies - if the car has ABS, stand on both the clutch and brake pedals and concentrate on steering with gentle input to avoid the obstacle.
Oh god, please don't spread such wrong ideas. While panic/emergency braking, you do not touch the clutch or change gears.

For emergency braking with ABS:
1) Jam the brakes fully and focus on the steering to avoid any collisions. ABS lets you steer with brakes fully pressed, that is its main purpose. Just ignore the clutch, you don't have the time to mess around with gears. Also ignore the violent kickback from the brakes, that means ABS is working.
2) Once the vehicle reaches stall point (stopping point actually), quickly switch to neutral. You can use the clutch for this, but not really necessary considering the panicky situation.

For controlled slow down (with or without ABS):
1) Gently press the brakes, and as the engine reaches stall point for that gear, engage clutch and down shift to the appropriate gear for the next speed you intend. Some people think you have to go from 5-4-3-2-1, not really. You can shift from 5 to 2, if you have slowed down enough.
2) ABS doesn't matter here because, gentle braking doesn't induce wheel locking unless you are on very slippery ground.

The wheel locking has nothing to do with speed and has everything to do with traction. ON very slippery ground, wheels can lock even at 10kmph, thus activating ABS.

You can understand these concepts very clearly if you do lot of wet trail offroading, and safely too, all under 15kmph speed. Trying to learn these on normal roads at higher speeds is risky and can be quite scary.

Last edited by Samurai : 16th September 2011 at 10:08.
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Old 16th September 2011, 10:19   #213
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai
Oh god, please don't spread such wrong ideas. While panic/emergency braking, you do not touch the clutch or change gears.

For emergency braking with ABS:
1) Jam the brakes fully and focus on the steering to avoid any collisions. ABS lets you steer with brakes fully pressed, that is its main purpose. Just ignore the clutch, you don't have the time to mess around with gears. Also ignore the violent kickback from the brakes, that means ABS is working.
2) Once the vehicle reaches stall point (stopping point actually), quickly switch to neutral. You can use the clutch for this, but not really necessary considering the panicky situation.
Thanks Samurai for stepping in. So, what they show in that video of pressing the clutch for panic situation is not correct.
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Old 16th September 2011, 10:26   #214
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
Oh god, please don't spread such wrong ideas. While panic/emergency braking, you do not touch the clutch or change gears.

For emergency braking with ABS:
1) Jam the brakes fully and focus on the steering to avoid any collisions. ABS lets you steer with brakes fully pressed, that is its main purpose. Just ignore the clutch, you don't have the time to mess around with gears. Also ignore the violent kickback from the brakes, that means ABS is working.
2) Once the vehicle reaches stall point (stopping point actually), quickly switch to neutral. You can use the clutch for this, but not really necessary considering the panicky situation.

For controlled slow down (with or without ABS):
1) Gently press the brakes, and as the engine reaches stall point for that gear, engage clutch and down shift to the appropriate gear for the next speed you intend. Some people think you have to go from 5-4-3-2-1, not really. You can shift from 5 to 2, if you have slowed down enough.
2) ABS doesn't matter here because, gentle braking doesn't induce wheel locking unless you are on very slippery ground.

The wheel locking has nothing to do with speed and has everything to do with traction. ON very slippery ground, wheels can lock even at 10kmph, thus activating ABS.

You can understand these concepts very clearly if you do lot of wet trail offroading, and safely too, all under 15kmph speed. Trying to learn these on normal roads at higher speeds is risky and can be quite scary.
At last, some sense!

A bit OT: I think it's very important that the above content should be cross posted in the "Best way to use clutch, gear and brakes" thread too.

http://www.team-bhp.com/forum/techni...ar-brakes.html (The best way to use the clutch, gear and brakes)

Cheers,
Vikram
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Old 16th September 2011, 10:38   #215
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by deetjohn View Post
Thanks Samurai for stepping in. So, what they show in that video of pressing the clutch for panic situation is not correct.
Everything shown in video is correct.
There is difference between slowing down from high speed and urgent braking for sudden stoppage.
You can slow down ( e.g. at toll on E way) using brakes only, without engaging clutch initially. But in panic situation when you need complete halt, it doesn't make much difference hence advisable to press brake as along clutch (no time to think about gear change and all that).
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Old 16th September 2011, 10:50   #216
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
Oh god, please don't spread such wrong ideas. While panic/emergency braking, you do not touch the clutch or change gears.

For emergency braking with ABS:
1) Jam the brakes fully and focus on the steering to avoid any collisions. ABS lets you steer with brakes fully pressed, that is its main purpose. Just ignore the clutch, you don't have the time to mess around with gears. Also ignore the violent kickback from the brakes, that means ABS is working.
2) Once the vehicle reaches stall point (stopping point actually), quickly switch to neutral. You can use the clutch for this, but not really necessary considering the panicky situation.
Disagree with you on this. When braking in an emergency specifically, that is. There are two reasons:

1. Most cars these days have an ECU which picks up on the impending stall on its own and ups the rpm by increasing fuel input. This increased motive force would act against the braking, hence increasing (albeit marginally) the braking distance. This is a big deal during an emergency, because every inch can make a difference between life and death - ones own or that of the cause of the emergency

2. In an emergency, 99% of all drivers will Not be able to concentrate on several things at the same time. The idea is to make it as simple as possible. I'm including myself in the 99% because I've never been in a "life and death" situation outside of theory or controlled practise. The simplest thing will be to stand on the brakes and the clutch (reflex) and concentrate on steering. Once on the brakes, one doesn't need to think about them any longer, and the singular focus is only to avoid the obstacle while not steering too much to overbalance the vehicle nor steering into opposing traffic/off the road (if there is a hill-face or steep drop, etc)

Also, the engine provides appreciable braking only if running at sufficiently high rpms. For petrol engines, that is above the high 3k range. In a high speed panic situation one generally (as in the case of this Captiva driver) would be in a high gear - and with the engine turning over at relatively low rpms the engine braking isn't really worth the risk of crashing because one is thinking about when to declutch by either listening to the engine or looking at the tacho. Vibrations from the engine can be ignored because one really wouldn't notice while being treated to a foot massage by the brake pedal.

PS. My idea is not wrong, it is just my (different) opinion. If you disagree, please say so instead of accusing me of "spreading" wrong ideas. I'm pretty sure my explanation would not convince one who is used to declutching at the last instance to change. However I am also certain that a driver unfamiliar with that technique would find the method I outlined simpler.
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Old 16th September 2011, 10:50   #217
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by deetjohn View Post
Thanks Samurai for stepping in. So, what they show in that video of pressing the clutch for panic situation is not correct.
IMO, the video is absolutely right. In panic, since you do not know/have time to choose the correct gear, it would be a good idea to disengage the clutch, brake like there is no tomorrow and come to a halt/steer past the obstacle.

I am talking this from experience, if for whatever reasons you stall the engine, forget ABS even your brakes do not work and Power steering goes dead and if you are an atheist, those few secs would leave you wondering what to do!!

I stalled my car (for reasons different than incorrect gear) on a curve and ended up spin wheeling with no control whatsoever on brakes and steering!


Quote:
Originally Posted by Samurai View Post
While panic/emergency braking, you do not touch the clutch or change gears.
So you mean to say, if someone has to panic brake from say 120 KMPH and fifth gear, he just slams the brake and come to a stop and should not change the gear or disengage the tranny?

Though I get your point, the argument is for your second point where you asked to switch to neutral, where you are actually agreeing with VeluM but stated that what he is proposing is ghastly!

When we are talking about emergency braking there is little time between we started braking hard and the Vehicle started to reach the stalling point.

Quote:
Originally Posted by comfortablynumb View Post
At last, some sense!


Vikram
Looks like you are mistaken!

Last edited by anilisanil : 16th September 2011 at 10:59.
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Old 16th September 2011, 11:14   #218
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

I agree with Samurai totally. You do not declutch (let alone go into Neutral) until the vehicle is almost stationary.

Rather get a stalled engine (if you must) than increase the stopping distance.
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Old 16th September 2011, 11:16   #219
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by sgiitk View Post

Rather get a stalled engine (if you must) than increase the stopping distance.
And lose the control over power steering and lose all the braking, good!
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Old 16th September 2011, 11:21   #220
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by VeluM View Post
Disagree with you on this. When braking in an emergency specifically, that is.

-----------------xxxxxxxxxxxxx-----------------------

by either listening to the engine or looking at the tacho. Vibrations from the engine can be ignored because one really wouldn't notice while being treated to a foot massage by the brake pedal.

PS. My idea is not wrong, it is just my (different) opinion. If you disagree, please say so instead of accusing me of "spreading" wrong ideas. I'm pretty sure my explanation would not convince one who is used to declutching at the last instance to change. However I am also certain that a driver unfamiliar with that technique would find the method I outlined simpler.

Yeah, i was wondering about this too.
If your instinct is to go for both brakes and clutch, go for it.
If youve learnt otherwise, use that.

but dont try to learn in actual situations.

You stall, and you lose every power assisted function.
that is not going to help anyone, except your repair centre.
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Old 16th September 2011, 11:24   #221
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by anilisanil View Post

So you mean to say, if someone has to panic brake from say 120 KMPH and fifth gear, he just slams the brake and come to a stop and should not change the gear or disengage the tranny?

Though I get your point, the argument is for your second point where you asked to switch to neutral, where you are actually agreeing with VeluM but stated that what he is proposing is ghastly!

When we are talking about emergency braking there is little time between we started braking hard and the Vehicle started to reach the stalling point.
Quote:
Originally Posted by VeluM View Post
2. In an emergency, 99% of all drivers will Not be able to concentrate on several things at the same time. The idea is to make it as simple as possible. I'm including myself in the 99% because I've never been in a "life and death" situation outside of theory or controlled practise. The simplest thing will be to stand on the brakes and the clutch (reflex) and concentrate on steering. Once on the brakes, one doesn't need to think about them any longer, and the singular focus is only to avoid the obstacle while not steering too much to overbalance the vehicle nor steering into opposing traffic/off the road (if there is a hill-face or steep drop, etc)



PS. My idea is not wrong, it is just my (different) opinion. If you disagree, please say so instead of accusing me of "spreading" wrong ideas. I'm pretty sure my explanation would not convince one who is used to declutching at the last instance to change. However I am also certain that a driver unfamiliar with that technique would find the method I outlined simpler.


Braking suddenly from 120 km/h does not require one to press the clutch. You press the clutch only when the car falls out of its power-band completely, and when the car is almost stationary or crawling, at which point you either switch to neutral or 1st gear, or 2nd, depending on the speed you're doing, once you've braked.

This is how it is done.

The clutch is never depressed, while braking. The basic function of the clutch is to facilitate smooth changing of gears. When you brake suddenly, you are not changing gears, you're coming to a halt, or a slow crawl.

Some argue that it is necessary to press the clutch, because it is easier to do so, considering that the speed is shed so quickly and the correct gear must be chosen after. Some argue that it will stall, if you don't press the clutch, but that's untrue. if you are not quick to react, you are bound to stall.

So if you are not quick to react, pressing the clutch is the easy way out. But it isn't the correct way. If you can't react quick enough, then I'm sorry but, one is not fit to drive on the highway in the first place. Just because it is a simpler technique doesn't make it the correct technique. It's just the simpler way out.

It's not just about concentrating on several things at once. The braking and then depressing of the clutch should come naturally and in a reflex manner. First brake, when you're almost at a crawl, then engage clutch and switch gear. You say 99% of the drivers cannot concentrate on such things. there is nothing to concentrate on here, this should happen by reflex, like how one changes gear by reflex, or turns the steering by reflex.

If you need to concentrate on getting it right, then I'm afraid the highway is still not the place to drive, for you, and for 99% of the others.

Last edited by suhaas307 : 16th September 2011 at 11:34.
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Old 16th September 2011, 11:41   #222
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by suhaas307 View Post
Braking suddenly from 120 km/h does not require one to press the clutch. You press the clutch only when the car falls out of its power-band completely, and when the car is almost stationary or in crawl, at which point you either switch to neutral or 1st gear, or 2nd, depending on the speed you're doing, once you've braked.

This is how it is done.

The clutch is never depressed, while braking. The basic function of the clutch is to facilitate smooth changing of gears. When you brake suddenly, you are not changing gears, you're coming to a halt, or a slow crawl.

Some argue that it is necessary to press the clutch, because it is easier to do so, considering that the speed is shed so quickly and the correct gear must be chosen after. Some argue that it will stall, if you don't press the clutch, but that's untrue. if you are not quick to react, you are bound to stall.

So if you are not quick to react, pressing the clutch is the easy way out. But it isn't the correct way. If you can't react quick enough, then I'm sorry but, one is not fit to drive on the highway in the first place.
I'm sorry, but your argument is opinionated and also pointless. Just because one person can react within a tenth of a second doesn't mean everyone can. Let us not bring reaction times into this argument because it adds nothing to the discussion.

It is agreed, however that there are two different ways of reacting in an emergency. Both have been outlined, and everyone is free to choose whichever suits them best. To each his own.

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but dont try to learn in actual situations.
Completely!
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Old 16th September 2011, 11:42   #223
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by suhaas307 View Post
Braking suddenly from 120 km/h does not require one to press the clutch. You press the clutch only when the car falls out of its power-band completely, and when the car is almost stationary or crawling, at which point you either switch to neutral or 1st gear, or 2nd, depending on the speed you're doing, once you've braked.
Take the case of Honda city. Braking distance of Honda city for 60 MPH-0 MPH is 123 feet.

To convert into meters, a City sedan if braked properly loses 97 KMPH (27 m/s) in a distance of 37 meters. That is about 1.4 secs, so what do you do in 1,4 secs? Start with just braking, look around to see if my engine is going to stall and then switch to neutral?

Thank you, but I am not a super computer.

Yes, I agree with you on how normal braking should be done. But in emergency we need to stop in a matter of seconds!!
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Old 16th September 2011, 11:51   #224
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by VeluM View Post
I'm sorry, but your argument is opinionated and also pointless. Just because one person can react within a tenth of a second doesn't mean everyone can. Let us not bring reaction times into this argument because it adds nothing to the discussion.

It is agreed, however that there are two different ways of reacting in an emergency. Both have been outlined, and everyone is free to choose whichever suits them best. To each his own.



Completely!
To call my argument opinionated and 'pointless', is rather juvenile.

If you cannot react quick enough, then you ought not to be driving at 120-140 km/h in the first place, my friend. It's as simple as that.

Quote:
Originally Posted by anilisanil View Post
Take the case of Honda city. Braking distance of Honda city for 60 MPH-0 MPH is 123 feet.

To convert into meters, a City sedan if braked properly loses 97 KMPH (27 m/s) in a distance of 37 meters. That is about 1.4 secs, so what do you do in 1,4 secs? Start with just braking, look around to see if my engine is going to stall and then switch to neutral?

Thank you, but I am not a super computer.

Yes, I agree with you on how normal braking should be done. But in emergency we need to stop in a matter of seconds!!
You don't have to be a supercomputer to drive correctly.

All it needs is practice, dedication, and the adopting correct method. Such things cannot be calculated in meters and seconds. If you have to brake, you have to brake. And when you know that you are going to come to a halt, or slow down to a crawl, then you need to be ready to change to a lower gear as soon as you come to a halt. You don't 'look around', you feel the car. So when you apply the brakes on your car, you should know, by the sound of the engine and the speed you're coming down to, as to which gear is appropriate for the same. That doesn't mean you keep the clutch pressed the whole time, so that it makes things easier for you.

Last edited by suhaas307 : 16th September 2011 at 11:52.
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Old 16th September 2011, 12:00   #225
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by suhaas307 View Post


You don't have to be a supercomputer to drive correctly.

All it needs is practice, dedication, and the adopting correct method. Such things cannot be calculated in meters and seconds. If you have to brake, you have to brake. And when you know that you are going to come to a halt, or slow down to a crawl, then you need to be ready to change to a lower gear as soon as you come to a halt. You don't 'look around', you feel the car. So when you apply the brakes on your car, you should know, by the sound of the engine and the speed you're coming down to, as to which gear is appropriate for the same. That doesn't mean you keep the clutch pressed the whole time, so that it makes things easier for you.

Ah! come on mate! It is good you could do a lot in those few seconds, I mean it really. But for most people it is less than even the reaction time! I mean we are taking about milliseconds!!

And I wonder how does it make it wrong to depress the clutch when you want to stop to a halt from high speeds. If you care to explain? How wrong is this wrong and why?

And what do you feel in the car for those few seconds? What if the road is undulated, what if you are on ABS and it is juddering, what if the music volume is bit high, what if the windows are down and someone is honking?

If I were you, I would rather concentrate on braking and steering past than wondering when to and to which gear to change to. And what if in panic you switch to a wrong gear?

Whatever may be the answer, lets agree to disagree! To each his own!!

Last edited by anilisanil : 16th September 2011 at 12:11.
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