Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 25th February 2012, 11:01   #361
Distinguished - BHPian
 
DerAlte's Avatar
 
Join Date: Mar 2007
Location: Bangalore
Posts: 8,066
Thanked: 2,864 Times
Default re: The ABS discussion thread

While not impossible, it is extremely rare for an ABS ECU to have failed. Perhaps you could check at another Hyundai A.S.S.? You could also test the ABS functionality by trying braking really hard (on an empty dirt road). If the ABS is OK you will feel the brake shudder even if you are trying it at 20-30Kmph.

A failed ABS ECU will not put you in harm's way as long as you are generally a careful driver, but having a dysfunctional ABS is a waste.
DerAlte is offline   Reply With Quote
Old 25th February 2012, 11:25   #362
Distinguished - BHPian
 
SS-Traveller's Avatar
 
Join Date: Jan 2009
Location: New Delhi
Posts: 6,490
Thanked: 10,019 Times
Default re: The ABS discussion thread

Quote:
Originally Posted by silverbyte View Post
The service center guy is telling me that my ABS module is reporting as "failed" in the scanner and he is suggesting that it will cost upward of 60-70 grand so I should not even try to get it replaced.
Just like that? No swap-and-check, no verification of scanner results, and what worthy advice to boot: that you shouldn't even try to get it replaced! The SCG (service centre guy) is turning out to be a seriously challenged goat.
SS-Traveller is offline   Reply With Quote
Old 17th June 2012, 12:17   #363
Senior - BHPian
 
Santoshbhat's Avatar
 
Join Date: May 2011
Location: Bangalore
Posts: 1,648
Thanked: 2,280 Times
Default Re: Accidents in India - PICS

Quote:
Originally Posted by vikram_d View Post
Nope ABS would not have helped. ABS works best on good clean roads. Throw sand or dirt into this picture and ABS goes completely bonkers. On loose surfaces like descirbed in the post, ABS will only make the braking distance longer. The problem with ABS is that it relies very heavily on the grip levels of the car/tyres. It works best when the tyres have maximum grip.
You are dead right. Precisely for this reason, sometimes I wish car makers gave us an 'ABS off' switch. At times on roads with lot of loose gravel and sand, the ABS simply unlocks the brakes and car just does not stop. A good driver one can easily modulate the brakes based on feel of grip avaialble/ loss or trasction etc... With ABS there is nothing the driver can do. At times I have have had to jump over some pretty nasty speed breakers coz the ABS just would not allow the brakes to grab the wheels.


Quote:
Originally Posted by raj_5004 View Post
Yes. ABS would have increased the braking distance but the car would not have skidded out of control. In short, the driver would have been able to steer the car to safety and thus avoid the collision.
Yes the idea of having ABS is to retain steering control which is not available when the wheels lock up. But what do you do when there is no room to steer the vehicle out of harm's way? You just want to minimise impact by reducing the speed of the vehicle. If in such a situation, the road is slippery, ABS can be counterproductive.

I am not against ABS per se. My point is that it has its downsides too. People have many misconceptions about ABS, which can be pretty dangerous.

Last edited by Santoshbhat : 17th June 2012 at 12:23.
Santoshbhat is offline   Reply With Quote
Old 17th June 2012, 13:17   #364
Senior - BHPian
 
vikram_d's Avatar
 
Join Date: Jul 2006
Location: Bangalore
Posts: 2,377
Thanked: 928 Times
Default Re: Accidents in India - PICS

The post with regards to which I wrote mentioned fine stone particles on the road. In such a case ABS would not help in anyway at all. It would lengthen the braking distance and would not help in steering the car.
vikram_d is offline   Reply With Quote
Old 17th June 2012, 15:42   #365
Senior - BHPian
 
rohanjf's Avatar
 
Join Date: Nov 2009
Location: Adelaide
Posts: 1,190
Thanked: 682 Times
Default

Quote:
Originally Posted by Santoshbhat View Post
You are dead right. Precisely for this reason, sometimes I wish car makers gave us an 'ABS off' switch. At times on roads with lot of loose gravel and sand, the ABS simply unlocks the brakes and car just does not stop.
While driving at 80 kmph on a highway, would it occur to any driver to press this button the moment she/he sees loose gravel as well as impending danger?

Or, while driving within the city, would it make sense for the driver to switch off ABS because the speed is less? I think not.

First of all, there should not be gravel on roads! Our laws, unfortunately, do not punish the tippers that keep dropping gravel on the move.
rohanjf is offline   Reply With Quote
Old 17th June 2012, 20:33   #366
Senior - BHPian
 
DRIV3R's Avatar
 
Join Date: Nov 2009
Location: India
Posts: 1,587
Thanked: 790 Times
Default Re: Accidents in India - PICS

Quote:
Originally Posted by rohanjf View Post
First of all, there should not be gravel on roads! Our laws, unfortunately, do not punish the tippers that keep dropping gravel on the move.
This, if implemented should end our cracked windshield woes as well!

Oh, and BTW, ABS with EBD does help in steering the car in emergency braking situations, irrespective of what surface the car is on! Period.
DRIV3R is offline   Reply With Quote
Old 17th June 2012, 21:35   #367
Senior - BHPian
 
Santoshbhat's Avatar
 
Join Date: May 2011
Location: Bangalore
Posts: 1,648
Thanked: 2,280 Times
Default Re: Accidents in India - PICS

Quote:
Originally Posted by rohanjf View Post
While driving at 80 kmph on a highway, would it occur to any driver to press this button the moment she/he sees loose gravel as well as impending danger?
No .

On one occasion I was driving through an internal state road just after heavy rains. Roads were wet and the heavy rains had washed down soil, mud, gravel etc... on to the roads. THe road itself was in bad condition and had some pretty big potholes. There were also many speed breakers along the way. Needless to say the grip levels were very poor. Keeping the conditions in mind my speeds were also very low. On many occasions when I hit the brakes (on seeing the potholes and humps) the tires would slide and ABS would unlock the brakes. As a result I was unable to modulate the brakes. Due to the ABS action, the car would just keep moving forward as the ABS was unable to hold on to the brakes since the tires were unable to grip. All this at speeds of 40 ~ 50 kph sometimes even as low as 20 kph. I am sure if I was driving a car without ABS I could have avoided thudding into some potholes or crashing over some speed bumps. On this particular drive I wished I could turn off ABS, hence my wish for the 'ABS off' switch.
Santoshbhat is offline   Reply With Quote
Old 18th June 2012, 01:03   #368
Senior - BHPian
 
khoj's Avatar
 
Join Date: Sep 2008
Location: Dilli
Posts: 2,702
Thanked: 1,230 Times
Default Re: Accidents in India - PICS

+1 to your post raj_5004 for being the only one on the subject that is spot on.

ABS is not a braking distance minimizer. It does gives the feeling though that the car is not stopping especially at speeds between say 35 to 80 kms/hr, as it actually is rolling to a standstill and not skidding away to glory (a condition confused with the brakes working at their optimum).

It is merely as Raj puts it a system that allows one to be able to successfully steer their vehicle in a situation of duress and drive out of it. That is all there is to it, no more no less.

Quote:
Originally Posted by raj_5004 View Post
Yes. ABS would have increased the braking distance but the car would not have skidded out of control. In short, the driver would have been able to steer the car to safety and thus avoid the collision.
khoj is offline   Reply With Quote
Old 18th June 2012, 01:29   #369
BHPian
 
swarnava.m's Avatar
 
Join Date: Oct 2011
Location: Mumbai/Margao
Posts: 631
Thanked: 253 Times
Default Re: Accidents in India - PICS

Quote:
Originally Posted by vikram_d View Post
...On loose surfaces like descirbed in the post, ABS will only make the braking distance longer. The problem with ABS is that it relies very heavily on the grip levels of the car/tyres. It works best when the tyres have maximum grip...
Quote:
Originally Posted by sbkumar View Post
Not sure if I got what you said right, but IMO ABS is meant to prevent wheel lock and loss of control in such circumstances ( like skidding in this case) though it may increase braking distances...
Quote:
Originally Posted by raj_5004 View Post
Yes. ABS would have increased the braking distance but the car would not have skidded out of control. In short, the driver would have been able to steer the car to safety and thus avoid the collision.
Quote:
Originally Posted by Santoshbhat View Post
Y...With ABS there is nothing the driver can do. At times I have have had to jump over some pretty nasty speed breakers coz the ABS just would not allow the brakes to grab the wheels...

I am not against ABS per se. My point is that it has its downsides too. People have many misconceptions about ABS, which can be pretty dangerous.
Quote:
Originally Posted by vikram_d View Post
The post with regards to which I wrote mentioned fine stone particles on the road. In such a case ABS would not help in anyway at all. It would lengthen the braking distance and would not help in steering the car.
So, in layman terms, in a single statement, how right or wrong is it to say that ABS actually increases our stopping distance? In other words, it reduces the braking capacity as compared to a car without ABS?
swarnava.m is offline   Reply With Quote
Old 18th June 2012, 02:11   #370
BHPian
 
Off Roadie's Avatar
 
Join Date: Jul 2008
Location: Mumbai
Posts: 279
Thanked: 115 Times
Default

Quote:
Originally Posted by rohanjf

While driving at 80 kmph on a highway, would it occur to any driver to press this button the moment she/he sees loose gravel as well as impending danger?

Or, while driving within the city, would it make sense for the driver to switch off ABS because the speed is less? I think not.

First of all, there should not be gravel on roads! Our laws, unfortunately, do not punish the tippers that keep dropping gravel on the move.
I agree to your points here but let's say if I were driving during the rains I would like the option of keeping the ABS off throughout.
There are quite a few instances where one may like to keep the ABS off so it is always better to have an option than not have one at all.
Off Roadie is offline   Reply With Quote
Old 18th June 2012, 02:16   #371
Distinguished - BHPian
 
Thad E Ginathom's Avatar
 
Join Date: Jun 2007
Location: Chennai
Posts: 7,204
Thanked: 5,818 Times
Default Re: Accidents in India - PICS

ABS only comes into action when your car would be skidding anyway. Thus, unless you drive, minute by minute, from one emergency to another, it doesn't even figure in your stopping, or your stopping distances for what, hopefuly, is almost all of your driving experience.

With (or without) respect, to all those who say, "Without ABS, I could have stopped," show me the control experiment in which you did. No, you cannot pump your brakes many times a second.

It is not much good on ice, or on loose grit --- but then, neither are cars without it.

Last edited by benbsb29 : 18th June 2012 at 14:56. Reason: Edited to be in context.
Thad E Ginathom is offline   (1) Thanks Reply With Quote
Old 18th June 2012, 04:08   #372
BHPian
 
Parthasarathig's Avatar
 
Join Date: Nov 2011
Location: Pothole-city
Posts: 887
Thanked: 487 Times
Default

Please read through the long post patiently.

IIRC the skidding of tyres in rains happens due to something called aquaplaning. This occurs when the car tyre comes onto water on the road and the water forms a layer between the road and the tyre. So when you brake the car, wheels lock up and as there is no traction in the tyres due to the water, the car starts skidding and you could almost end up in a bad crash.

The trick of driving in the rains(as id read in an auto mag) is not to keep the brakes pressed but to press and release and then press and release. What this does is keeps the tyre rotating, so in case its aquaplaned, on rotating the tyre drives away the water and stays in contact with the road.

This of course was in the days when there was very few ABS enabled cars in the sub 10lac category in the country almost about 10 years back and the author happened to have mentioned this method to be applied in ABS deficient cars.

What the author was trying to do in a normal car was the same as ABS will be doing i.e prevent wheels from locking up and therefore prevent aquaplaning as the wheels keep rotating.
Thus ABS actually helps to drive to safety in case of loss of contact with the road due to watery surface. ABS combined with EBD all the more helps as the brake force gets distributex to the wheel having the most traction i.e in more contact with the road, and thus in turn helps you to steer clear of the danger.

The basic idea here is loss of traction that causes the accidents. Our cars dont come with ESP or TCS both of which are synonyms for traction control systems which transfer power to the wheel having the most traction unlike EBD which brakes the wheel with the most traction.

If ABS is combined with TCS then driving in the rains or lose gravel will be much more safer. With ABS i feel we are safe only on the plain roads. But not on gravel for which i feel tcs makes it much more safer with consistent traction and power to the appropriate wheel.

Feel free to correct me if Im wrong.

Regards.
Parthasarathig is offline   Reply With Quote
Old 18th June 2012, 07:18   #373
Senior - BHPian
 
mayankk's Avatar
 
Join Date: Apr 2010
Location: New Delhi
Posts: 3,988
Thanked: 3,097 Times
Default

Quote:
Originally Posted by Parthasarathig
Please read through the long post patiently.

IIRC the skidding of tyres in rains happens due to something called aquaplaning. This occurs when the car tyre comes onto water on the road and the water forms a layer between the road and the tyre. So when you brake the car, wheels lock up and as there is no traction in the tyres due to the water, the car starts skidding and you could almost end up in a bad crash.

The trick of driving in the rains(as id read in an auto mag) is not to keep the brakes pressed but to press and release and then press and release. What this does is keeps the tyre rotating, so in case its aquaplaned, on rotating the tyre drives away the water and stays in contact with the road.

This of course was in the days when there was very few ABS enabled cars in the sub 10lac category in the country almost about 10 years back and the author happened to have mentioned this method to be applied in ABS deficient cars.

What the author was trying to do in a normal car was the same as ABS will be doing i.e prevent wheels from locking up and therefore prevent aquaplaning as the wheels keep rotating.
Thus ABS actually helps to drive to safety in case of loss of contact with the road due to watery surface. ABS combined with EBD all the more helps as the brake force gets distributex to the wheel having the most traction i.e in more contact with the road, and thus in turn helps you to steer clear of the danger.

The basic idea here is loss of traction that causes the accidents. Our cars dont come with ESP or TCS both of which are synonyms for traction control systems which transfer power to the wheel having the most traction unlike EBD which brakes the wheel with the most traction.

If ABS is combined with TCS then driving in the rains or lose gravel will be much more safer. With ABS i feel we are safe only on the plain roads. But not on gravel for which i feel tcs makes it much more safer with consistent traction and power to the appropriate wheel.

Feel free to correct me if Im wrong.

Regards.
sorry,but aquaplaning has nothing to do with brakes.
anytime time contact is lost,in this case, between the tyre and road surface because of a layer of water between them....aquaplaning.
doesnt matter if the tyre is rotating or on brakes.
abs,ebd,anything wont help if all wheels of the car have this ,er, tiff with water.
mayankk is online now   (1) Thanks Reply With Quote
Old 18th June 2012, 11:03   #374
BHPian
 
Parthasarathig's Avatar
 
Join Date: Nov 2011
Location: Pothole-city
Posts: 887
Thanked: 487 Times
Default

Quote:
Originally Posted by mayankk

sorry,but aquaplaning has nothing to do with brakes.
anytime time contact is lost,in this case, between the tyre and road surface because of a layer of water between them....aquaplaning.
doesnt matter if the tyre is rotating or on brakes.
abs,ebd,anything wont help if all wheels of the car have this ,er, tiff with water.
now i feel kinda scared. Then what is the safest option for driving on rainy roads? I frequently travel in buses too on highways. So how safe are buses with regards to this? Especially ksrtc buses.
The only safe option im guessing now is to drive very slowly in watery roads.
And regarding gravel, tcs does help. As ive seen many landrover videos having a tcs option labelled as gravel.
Parthasarathig is offline   Reply With Quote
Old 18th June 2012, 11:10   #375
Senior - BHPian
 
mayankk's Avatar
 
Join Date: Apr 2010
Location: New Delhi
Posts: 3,988
Thanked: 3,097 Times
Default

Quote:
Originally Posted by Parthasarathig

now i feel kinda scared. Then what is the safest option for driving on rainy roads? I frequently travel in buses too on highways. So how safe are buses with regards to this? Especially ksrtc buses.
The only safe option im guessing now is to drive very slowly in watery roads.
And regarding gravel, tcs does help. As ive seen many landrover videos having a tcs option labelled as gravel.
Slow down when wet.
Give the tyre time to part the water, either by diverting it or displacing it.

I really don't have any idea of buses.
I am assuming their mass and relatively low speed could help prevent aquaplaning, but I may also be talking through my hat.
mayankk is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
The DATA Card and USB Modem discussion thread (Reliance/Airtel/Tata) sk456 Gadgets, Computers & Software 720 11th December 2015 09:00
Windows Vista Discussion Thread normally_crazy Gadgets, Computers & Software 663 2nd December 2014 02:18
Chennai General Discussion Thread slipstream The Team-BHP Meet Section 11 9th August 2006 15:43


All times are GMT +5.5. The time now is 08:26.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks