motor

Silvia_Drift · 02-23-2004, 02:19 PM

Hey guys. I am driving a 2001 Subaru Legacy and I am having a problem with the technique used to stop the car in the snow. In dry weather or rain, the brakes work perfect. But, in the snow, when I push the brake pedal down till the ABS kicks in, the brake pedal rapidly modulates making a large noise and it seems as though the car could stop faster if the brakes locked up. It is very hard to slow down from hhigh speeds. Is this normal with ABS brakes? If so, how do I stop the car faster?

TT · 02-23-2004, 02:31 PM

The car won't stop faster if the brake would be able to lock the wheels... with cars with ABS, if the ABS is ok, there is only one way to stop faster.. push the pedal and wait... you can't pretend to stop on the snow as you do on dry or wet tarmac... but obviously even ABS can't do wonders on snow or ice...

Silvia_Drift · 02-23-2004, 02:35 PM

Originally Posted by TT

The car won't stop faster if the brake would be able to lock the wheels... with cars with ABS, if the ABS is ok, there is only one way to stop faster.. push the pedal and wait... you can't pretend to stop on the snow as you do on dry or wet tarmac... but obviously even ABS can't do wonders on snow or ice...

Hmm, I recently drove a crappy 1987 Toyota Camry without ABS and it seemed to stop a bit faster but the car got a bit sideways when the brakes locked. What would stop faster with an ABS equipped car? Hitting the pedal as hard as possible or lightly pushing the brakes so that the ABS does not have to work? And would pumping the brakes make the car stop faster?

TT · 02-23-2004, 02:44 PM

I repeat.. usually with every ABS, they better stopping power is obtained pushing the pedal as hard as you can.. since the CPU will be able to brake as much as possible w/o stopping the wheels.. you could do it by yourself, but the machine basically can "feel" if the wheels are blocked way better than you

Wide · 02-23-2004, 02:47 PM

When u hit the pedal as hard as possible ABS cant do its work well.. Cause the surface is icy or snowy.. I think when u hit enough pedal without activatin the ABS u can stop at a shorter distance..

TT · 02-23-2004, 02:50 PM

I think when u hit enough pedal without activatin the ABS u can stop at a shorter distance..

But how can you know how much is "enough"? Maybe you could push a little more... of course the ABS can't do wonders on ice and snow, but still if we are not talking about 200 km/h were anyway it's useless to brake you can could just go straight and aim for the smallest tree

, at normal speeds the ABS will just help you and also avoid (at least a little)

graywolf624 · 02-23-2004, 02:51 PM

When u hit the pedal as hard as possible ABS cant do its work well.. Cause the surface is icy or snowy.. I think when u hit enough pedal without activatin the ABS u can stop at a shorter distance..

False.

In an abs car you should hit the pedal flat to the floor in mud and snow. The actual modulation is exactly that of pumping the brake in a non abs car. It is just keep the car at the point of maximum torque before the tires lock up. It is done by determining how fast the tires are decellerating using a speed sensor in the wheel.
An abs system can pump the brakes on its own faster then you ever could. Thus never pump the brakes in an abs car.

TT · 02-23-2004, 02:52 PM

Phew, thanks gray for coming and help me out

Silvia_Drift · 02-23-2004, 03:04 PM

Ok, thanks for the help guys.

RallyeNLD · 02-23-2004, 04:21 PM

Sorry, all wrong. Locking your wheels in fresh snow IS the fastest way to stop your car!!! By locking your wheels snow will build up in front of your tire and stop the wheel. This doesn't happen with ABS. On ice I preffer ABS though.

PennStateFSAE · 02-23-2004, 04:58 PM

Ehh...how many times are you in fresh snow deep enough for snow to build up? I guess I am speaking for the northeast US. But the density and viscosity of fresh snow is so low...I find it hard to believe it would make a difference. I agree that locking the brakes is faster in sand but on packed snow you'll never dig in enough because the depth of snow on the road is usually pretty low (with an ice base anyway).

TT · 02-23-2004, 07:19 PM

Originally Posted by RallyeNLD

Sorry, all wrong. Locking your wheels in fresh snow IS the fastest way to stop your car!!! By locking your wheels snow will build up in front of your tire and stop the wheel. This doesn't happen with ABS. On ice I preffer ABS though.

Don't know how are winters in your town, but I never saw enough fresh snow on the road to use this techinique :roll:

Sp00ln · 02-23-2004, 07:22 PM

Not only will you prolly stop better/faster in the snow if you have ABS, but you'll get a foot massage while your at it!

kteo2003 · 02-23-2004, 08:06 PM

the big advantage that you have is not only that the car brakes but if it is neccesery you can turn your wheels and the car will obey...so you can avoid to crash to someone or something....instead with the wheels locked the car will go in a straight line...

spicymustard · 02-23-2004, 08:17 PM

My Subaru WRX stops great in the snow or ice with ABS, yea it activates really quickly, almost as soon as i start to break, but i have always stoped before i reach the car infront of me. I would imagine that your subaru has the same abs technology. If you want to try out the no abs fina a large snowy parking lot and pull the abs fuse. I am sure however that you will stop much faster with it on.