ABS vs. Brake Pumping

[Skotty]

I've done some experiments with my '97 Cadillac Seville STS in slippery conditions. I've found that I can brake faster by "pumping the brakes" than by mashing them and letting the ABS control slip.

Has anyone else experimented with this on their ABS cars? What did you find out? I would expect ABS to be superior, but maybe mine doesn't just because it's old. Does an ABS system lose effectiveness as it gets older? I doubt it. I figure it's more of a "it either works or it doesn't" kind of system. If so, maybe the system installed on '97 Cadillacs just isn't that good.

 

[leftyman]

97 Cadillac Seville STS 😀 like anything could stop that tank.

 

[Aikouka]

I don't remember... but aren't you not supposed to pump ABS brakes?

 

[xanis]

Haven't driven a car without ABS but it seems like that a computer-controlled brake pumping would be more effective.

 

[d3n]

Originally posted by: Aikouka
I don't remember... but aren't you not supposed to pump ABS brakes?

No, The master cylinder/brake ECU can handle the situation much quicker than you can. Just mash em if you have em on ABS brakes.

 

[Tiamat]

I used to drive an 84 caravan (maybe it was 83) that did not have ABS brakes. I found that using the brakes at all in slippery conditions would cause the car to slide. I just learned to drive such that I wouldnt be placed in a position where using the brakes suddenly was a huge necessity.

 

[Skotty]

Originally posted by: Aikouka
I don't remember... but aren't you not supposed to pump ABS brakes?

I think you are not supposed to have to pump ABS brakes, as they can do the pumping for you. But I pitted my own abilities against my ABS system and I won. I know the ABS was trying to do it's job because you can hear it and feel it in the peddle.

 

[clamum]

My car doesn't have anti-lock brakes and my mom's does (2000 or 2001 Camry). Her's brakes quite a bit better compared to pumping my brakes.

 

[Aikouka]

Originally posted by: Skotty
I think you are not supposed to have to pump ABS brakes, as they can do the pumping for you. But I pitted my own abilities against my ABS system and I won. I know the ABS was trying to do it's job because you can hear it and feel it in the peddle.

The driver must never "pump" the brakes though, because the main function of ABS in fact is to "pump" those brakes up to 15 times per second. Instead you must apply the brakes firmly and steadily, otherwise if you release the brake pedal the system will be deactivated. Many drivers have a tendency to release the pedal when ABS is active because they feel it somewhat pulsating through their foot. But this pulsation is normal, and it is caused by the system's pumping action.

From some Canadian Auto Press thing, so take it with a gain of salt 😛.

 

[Mark R]

ABS should win:
It can pump the brakes much faster than you can
It can detect slip much faster than you can - i.e. it can detect when 1 wheel slips - it's often not possible to feel the instability until at least 2 lock
ABS will pump each wheel individually, only when that wheel slips or is about to slip. Manual pumping can only control all the wheels together

There are 2 circumstances where ABS can be a disadvantage - because in these 2 unusual situations locking the wheels is better:
Deep snow
Deep gravel

In these circumstances, a locked wheel will act like a snow-plough and pile the gravel or snow up in a wall in front of the wheels. If the wheels are allowed to roll, this effect is reduced.

 

[OutHouse]

ABS is far better then brakes with no ABS that you have to pump.

 

[mugs]

Originally posted by: Aikouka

Originally posted by: Skotty
I think you are not supposed to have to pump ABS brakes, as they can do the pumping for you. But I pitted my own abilities against my ABS system and I won. I know the ABS was trying to do it's job because you can hear it and feel it in the peddle.

The driver must never "pump" the brakes though, because the main function of ABS in fact is to "pump" those brakes up to 15 times per second. Instead you must apply the brakes firmly and steadily, otherwise if you release the brake pedal the system will be deactivated. Many drivers have a tendency to release the pedal when ABS is active because they feel it somewhat pulsating through their foot. But this pulsation is normal, and it is caused by the system's pumping action.

From some Canadian Auto Press thing, so take it with a gain of salt 😛.

I love when it snows because then I can play with my ABS brakes in my driveway. The pulsating feeling is cool. 😱

 

[GagHalfrunt]

Originally posted by: Skotty
I've done some experiments with my '97 Cadillac Seville STS in slippery conditions. I've found that I can brake faster by "pumping the brakes" than by mashing them and letting the ABS control slip.

If you really believe that do the world a favor, sell your POS car and buy a tricycle. Nobody on earth can come CLOSE to pumping the brakes fast enough to outperform an ABS system.

 

[Aikouka]

Originally posted by: mugs
I love when it snows because then I can play with my ABS brakes in my driveway. The pulsating feeling is cool. 😱

I don't really pay attention to things like that much. The feeling of my tendons being messed up in my foot is much more mind-grasping than the pulsating of the pedal 😛. Kinda sucks when you gotta drive 30 miles to work one way and your foot can't stand more than 20... damn bowling (yes, bowling) messed up my tendons in my foot 🙁.

 

[jtvang125]

I'm assuming ABS would excel in panic stops too since many people just slam on their brakes during the incident.

 

[Skotty]

Note by "pumping the brakes" manually, I don't really mean pumping them fast as an ABS system would do. I mean applying them as firmly as you think possible, and when the car starts to slip, you ease off and reapply. Basically trying to ride the fine line at the brink of slipping. Doing it manually, you might be pumping once per second.

When I did my tests, it was on tightly packed compressed snow on a street that wasn't well bladed and had started to melt and refroze at least once. Not as slick as a sheet of ice, but pretty slick. I need to run tests on different slick surfaces, but the day I did testing, I did a better job (i.e., I was able to stop the car in less distance than my ABS system). I didn't disable the ABS for my tests, so it's possible the ABS may have kicked in however briefly on my manual pumps.

I agree that ABS should do a better job. But in my tests, it didn't. Just wondering if others have played around with this.

 

[BD2003]

Originally posted by: Skotty
Note by "pumping the brakes" manually, I don't really mean pumping them fast as an ABS system would do. I mean applying them as firmly as you think possible, and when the car starts to slip, you ease off and reapply. Basically trying to ride the fine line at the brink of slipping. Doing it manually, you might be pumping once per second.

When I did my tests, it was on tightly packed compressed snow on a street that wasn't well bladed and had started to melt and refroze at least once. Not as slick as a sheet of ice, but pretty slick. I need to run tests on different slick surfaces, but the day I did testing, I did a better job (i.e., I was able to stop the car in less distance than my ABS system). I didn't disable the ABS for my tests, so it's possible the ABS may have kicked in however briefly on my manual pumps.

I agree that ABS should do a better job. But in my tests, it didn't. Just wondering if others have played around with this.

Well, you've managed to figure out that there are some situations where you can brake a bit quicker by pumping manually, but I'd love to see you try to dodge a real obstacle in the same situation.

Remember, ABS isnt about shortening stopping distance, it's about allowing you to maintain control while doing so. ABS has saved my ass numerous times.

 

[Old Hippie]

When I did my tests, it was on tightly packed compressed snow on a street that wasn't well bladed and had started to melt and refroze at least once.

You may be able to beat ABS in straight line stopping. Think you could do it @ 40-60mph while steering around an accident or obstruction? ABS can.