Interesting observation about ABS and 02 WRX

[Scooby Don't]

CompUser wrote:




I noticed this in my car, too. When one side is on ice,
the ABS tends to lift the brakes on all four wheels.
This almost sent me rolling into an intersection once.
Is it really supposed to do this?

The ABS in the 2002 WRX is dangerous. I have one and it's effing Scary
in the snow especially when you are going slow down a hill. You will
NOT stop. I hear all the naysayers in here but they are wrong and
probably don't own the car or are not used to ABS that actually works.
The dealers say the ABS very sensitive. I like Subaru but it's going
to take a massive lawsuit for them to wake up and FIX the problem. My
WRX is going up for sale in 2 weeks as I'm moving. But I won't buy
another. Supposedly the 2004 WRX has no ABS problems but Subaru should
come clean and fix the sensitivity issue. if I slide into an
intersection and get hit I would be phoning my lawyer and others to
test the car.

 

[Rob Munach]

CompUser wrote:





I noticed this in my car, too. When one side is on ice,
the ABS tends to lift the brakes on all four wheels.
This almost sent me rolling into an intersection once.
Is it really supposed to do this?

My Forester does that too. This is totally unsafe. I am tempted to
disconnect the system. I may give NHTSA a call.

 

[BoB]

CompUser wrote:




I noticed this in my car, too. When one side is on ice,
the ABS tends to lift the brakes on all four wheels.
This almost sent me rolling into an intersection once.

Is it really supposed to do this?

Well lets say it is designed to work that way. I can't believe
the computer could not be programmed to detect a low speed or
rpm, say 5 mph, and allow you to at least 'try' to stop the car
by automatically disabling ABS. How relevant are ABS features
when you are barely moving?

I'm not saying ABS doesn't have its advantages, I'm saying they
have had a long time to perfect ABS, but they aren't there yet.

Subaru owner since 1990.

BoB

 

[S]

Hi All!

It _is_ normal behaviour. You've no friction force acting on the left
hand side of the car (it's on snow/ice). If the brakes on the right
side were to be applied (such as would happen in a non-ABS equipped
car), guess what would happen? The entire car would rotate clockwise
(as viewed from above) about its center of mass. You'd now be getting
T-boned by traffic approaching in the lane to your right.

Not so. I just had to try, so I took my WRX (with the ABS off) and
found an appropriate patch of ice. Several hard stops from ~20MPH with
the right tires on ice, and the left ones on wet pavement, the car
stopped straight with no problems, only a slight pull to the left. I
braked hard enuf to lock 'em up on one pass, in this instance the rear
_did_ step out a bit, but lifting off of the brake snapped it back in
line again.
Guess I shoulda tried with the ABS on, but I didn't.
Thought you'd like to know . . .

ByeBye! S.

Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101

 

[Tony Hwang]

It _is_ normal behaviour. You've no friction force acting on the left
hand side of the car (it's on snow/ice). If the brakes on the right
side were to be applied (such as would happen in a non-ABS equipped
car), guess what would happen? The entire car would rotate clockwise
(as viewed from above) about its center of mass. You'd now be getting
T-boned by traffic approaching in the lane to your right.

Bottom line, you need to expect this behavior in an ABS-equipped car,
and modify your driving style accordingly.

Hi,
That is why you can have traction control in addition to AWD and ABS.
Tony

 

[2 Stroke]

Bob,

Do you own a 2002-2003 WRX?

Steve Hansen,
Lomita, CA

==========================

 

[Osiris]

The interesting point here is the assumption that with ABS disconnected,
and the subsequent total lock-up of the wheels, the driver would have
had some sort of steering control.

This is totally UNTRUE. Loss of traction also means loss of steering...
and loss of control.

The drivers best course of action would have been to let go the brakes,
and try to steer away from the pile up, with controlled and gentle
application of throttle. Alternatively, even with the wheels travelling
at only 5mph, she could have simply selected reverse gear (with a small
amount of gear crunching) and attempted to slow the car with the AWD
system driving in reverse.

Not recommended at most times, but certainly cheaper than $4000 repair bill

Cheers
Osiris

 

[BoB]

The interesting point here is the assumption that with ABS disconnected,
and the subsequent total lock-up of the wheels, the driver would have
had some sort of steering control.

This is totally UNTRUE. Loss of traction also means loss of steering...
and loss of control.

The drivers best course of action would have been to let go the brakes,
and try to steer away from the pile up, with controlled and gentle
application of throttle. Alternatively, even with the wheels travelling
at only 5mph, she could have simply selected reverse gear (with a small
amount of gear crunching) and attempted to slow the car with the AWD
system driving in reverse.

Had I been driving, I would have tried the emergency brake first and
it was obviously not going to stop me, my next move would have been to
try reverse.

I was riding through a downtown section back in the 60's, when the
brakes totally failed on a Pontiac. There were pedestrians in the
crosswalk shortly ahead and he did not hesitate to throw the automatic
into reverse and hit the gas briefly. He managed to not hit 'park' and
we stopped fast. We were amazed that it did not appear to damage a
thing at about 25 mph on drive pavement. We crept a few blocks to the
garage.