Disable ABS

[S]

Hi Tom, All!

Maybe you need better tires. After all, tires are critical for good
traction. I use snow tires in the winter, and ABS works better because
ABS, of course, still relies on traction. Ain't no magic without
friction between tire and surface.

True. Putting studded snows on m'ladys Forester made a huge
difference. I use the Michelin Alpin Pilots on my rex. They just don't
offer enough grip on ice (despite being offered as an "ice" tire; the
Arctic Alpin is much better, and no longer available, naturally) to
get the ABS to work properly.
The real problem, tho, seems to be in the way the ABS control
modulates the brake pressure. The Subaru unit seems to pulse the
brakes a lot slower than the GM I was comparing it to; Subaru is a
definite on-off-on-off sensation, while the Caddy is more of a
HUMMMMMMM.
The dirt road issue is, I think, an entirely different thing, and may
be common to all ABS systems (never tried _this_ with the Caddy ;-).
When braking hard into a bumpy corner (washboards), the tires
experience less grip, (and hence some wheel lock-up) as they skip thru
the bumps. The ABS responds by modulating the brake pressure, giving
the sensation of drastically reduced braking.
You'd probably never notice this driving at rational speeds, but when
cornering at the limits of traction, the effect is extremely
disconcerting, and may result in a quick trip into the ditch at the
outside of the corner! Trust me; I have tried both ways looking for
that edge, and the difference is dramatic. With the ABS off, the WRX
will hammer an apex and rocket out of a turn with very little fuss;
point it and put the pedal down. With the ABS on, it is difficult to
"turn in" to the apex properly; you either have to begin braking way
early, or aim for an apex way short of where you really want to be,
and then wait until things settle before getting back on the gas,
neither of which results in a fast line thru the turn.

ByeBye! S.


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

 

[iksalama]

Maybe you need better tires. After all, tires are critical for good
traction. I use snow tires in the winter, and ABS works better because
ABS, of course, still relies on traction. Ain't no magic without friction
between tire and surface.

I still haven't seen any convincing arguments in favor of disabling ABS. I
gather there are reasons when you are racing, but I don't see any for
driving on public roads, trying to get places.

Reasons for disabling ABS:

1. You can actually stop faster without it. ABS was designed to allow you
to manuever your car while stomping on the pedal, not necessarily stop you
faster, in some cases it does have the affect of stopping you faster, but in
my WRX that is not the case.

2. Being able to actually lock the brakes can be advantageous for certain
auto-x or roadcourse type races.

3. The ABS in the WRX is WAAAAAAAYYYYY Y too touchy and has been documented
by many nasioc people to engage while going over bumps w/o the pedal
depressed.

4. Trusting ones own instincts over those of a machine, I prefer being in
control.

5. I've found that big brake kits tend to suffer when using ABS in
conjunction with them as the ABS computer (for lack of better terminology)
is programmed to apply "w" amount of pressure on a "x" sized rotor that
weighs "y" more/less than stock w/ "z" number of pots on the caliper.
Change either "x" "y" or "z" and the formula is messed up. Same theory
would apply if he went with a larger/smaller or heavier/lighter wheel & tire
combo.

 

[CompUser]

by many nasioc people to engage while going over bumps w/o the pedal
depressed.

You're saying the WRX ABS causes brakes to
"apply", with no brake pedal depression??


First I've heard of that one!

 

[Edward Hayes]

Many complaints seem to be caused by drivers running excessively high
tire pressures and hitting bumps. ABS activating without a foot on the
brake pedal? I never heard that one.

 

[Carl 1 Lucky Texan]

just today at Nasioc I saw a 'tbs'/recall (sorry, don't recall which
now) for '02 WRX ABS brake issue. Seems Subaru and NHTSA agreed the ABS
can be disconcertingly slow to engage and some type of sensitivity
adjustment can be made.
Seems somewhat opposite of the complaint here.
I dunno.

Carl

 

[Mark Carroll]

We own one car with ABS, and one without. I'll take ABS under ANY
conditions hands down. They work better in the wet, the dry, the snow and
yes, on gravel too; and we have ALL of those conditions where I live.[/QUOTE]

I like ABS, too - I find it helpful in the snow. I finally got around
to looking in the WRX manual's ABS section, though, and it says,

"When driving on badly surfaced roads, gravel roads, icy roads, or
over deep newly fallen snow, stopping distances may be longer for a
vehicle with the ABS system than one without."

Clearly they have /some/ reason for writing that. Then again, my
understanding was that ABS was usually better for giving you extra
ability to steer when braking rather than for reducing the stopping
distance.

-- Mark

 

[iksalama]

http://forums.nasioc.com/forums/showthread.php?t=690090&highlight=ABS+Sensitive

the above has a lot more insight on what I meant by ABS engages, The brakes
themselves don't engage when going over a bump, but the ABS system can
engage giving you zero braking power for a full second after hitting a bump.
I should have been more clear.

 

[xmirage2kx]

Reasons for disabling ABS:

1. You can actually stop faster without it. ABS was designed to allow
you
to manuever your car while stomping on the pedal, not necessarily stop
you
faster, in some cases it does have the affect of stopping you faster,
but in
my WRX that is not the case.

2. Being able to actually lock the brakes can be advantageous for
certain
auto-x or roadcourse type races.

3. The ABS in the WRX is WAAAAAAAYYYYY Y too touchy and has been
documented
by many nasioc people to engage while going over bumps w/o the pedal
depressed.

4. Trusting ones own instincts over those of a machine, I prefer
being in
control.

5. I’ve found that big brake kits tend to suffer when using ABS
in
conjunction with them as the ABS computer (for lack of better
terminology)
is programmed to apply "w" amount of pressure on a "x" sized rotor
that
weighs "y" more/less than stock w/ "z" number of pots on the caliper.
Change either "x" "y" or "z" and the formula is messed up. Same
theory
would apply if he went with a larger/smaller or heavier/lighter wheel
& tire
combo.

1. Not really the case, while sometimes it causes you to stop longer,
it is not designed to, and it is not designed to "allow you to
manuever" either, just allow you to remain in control.

2. Yes, every now and then not having ABS is good, but really only in
extreme cases, not day to day.

3. w/o pedal depressed?!?! if that has ever happened its a flaw
elsewhere, not a flaw with the ABS, if it goes off over a bump thats
gotta be a big enough bump to depress the pedal by shock value alone,
or cause the sensor to read as such.

4. VERY VERY VERY few people have better reaction time than a
computer, and the few that do can still be caught offguard. differing
your driving style is needed for ABS vs Non-ABS, just like Auto vs
Stick. Just gotta know how your car handles and adjust.

5. not sure the effect of big brake kits; but it is safe to assume
that anytime you alter the braking system it will preform differently;
and if the computer is unable to learn big brakes then an adjustment
should be made so the system know what to do.

 

[CompUser]

http://forums.nasioc.com/forums/showthread.php?t=690090&highlight=ABS+Sensitive

the above has a lot more insight on what I meant by ABS engages, The brakes
themselves don't engage when going over a bump, but the ABS system can
engage giving you zero braking power for a full second after hitting a bump.
I should have been more clear.

Ok, that's *completely* different from what was
clearly said initially.

Oh, BTW...if you're braking and running over a
surface that's rough/ripply enough to get wheel
(s)intermittently "airborne" and out of contact
with the road surface, yes, the ABS will tend to
activate on the wheel(s) that are no longer in
contact with the road surface, possibly still
with ABS operating on them for a short period
after they return to contact with the road.

ANY vehicle that has ABS, not just the WRX, will
do that.

 

[CompUser]

@newssvr17.news.prodigy.com>, (e-mail address removed)
says...

just today at Nasioc I saw a 'tbs'/recall (sorry, don't recall which
now) for '02 WRX ABS brake issue. Seems Subaru and NHTSA agreed the ABS
can be disconcertingly slow to engage and some type of sensitivity
adjustment can be made.
Seems somewhat opposite of the complaint here.
I dunno.

Is this the old one from a couple of years ago,
or something new?

 

[CompUser]

"When driving on badly surfaced roads, gravel roads, icy roads, or
over deep newly fallen snow, stopping distances may be longer for a
vehicle with the ABS system than one without."

Clearly they have /some/ reason for writing that.

Because it's true. ;-)

Then again, my
understanding was that ABS was usually better for giving you extra
ability to steer when braking rather than for reducing the stopping
distance.

That's basically it!

 

[Carl 1 Lucky Texan]

ABS service bulletin thread;

http://tinyurl.com/9sj3n

Carl

 

[CompUser]

@newssvr22.news.prodigy.net>, (e-mail address removed)
says...

ABS service bulletin thread;

http://tinyurl.com/9sj3n

Thanks Carl...it is new.

The fact that NHTSA investigated and dismissed
any safety concern, and Subaru *still* took
action to address it, impresses me favorably.

 

[iksalama]

Ok, that's *completely* different from what was
clearly said initially.

My original post was "The ABS in the WRX is WAAAAAAAYYYYY Y too touchy and
has been documented by many nasioc people to engage while going over bumps
w/o the pedal depressed." I don't know if its *completely* different. I
said it engages, not applies the brakes. Though I wasn't 100% clear the way
I worded it and I apologize.

Oh, BTW...if you're braking and running over a
surface that's rough/ripply enough to get wheel
(s)intermittently "airborne" and out of contact
with the road surface, yes, the ABS will tend to
activate on the wheel(s) that are no longer in
contact with the road surface, possibly still
with ABS operating on them for a short period
after they return to contact with the road.

ANY vehicle that has ABS, not just the WRX, will
do that.

Yes, but the WRX ABS system will at times have the above scenario happen
even when drivers are not on the brakes going into the bump but apply the
brakes shortly thereafter and have no brakes for about 1 second....lots of
bad things can happen in one second.

 

[iksalama]

1. Not really the case, while sometimes it causes you to stop longer,
it is not designed to, and it is not designed to "allow you to
manuever" either, just allow you to remain in control.

2. Yes, every now and then not having ABS is good, but really only in
extreme cases, not day to day.

3. w/o pedal depressed?!?! if that has ever happened its a flaw
elsewhere, not a flaw with the ABS, if it goes off over a bump thats
gotta be a big enough bump to depress the pedal by shock value alone,
or cause the sensor to read as such.

4. VERY VERY VERY few people have better reaction time than a
computer, and the few that do can still be caught offguard. differing
your driving style is needed for ABS vs Non-ABS, just like Auto vs
Stick. Just gotta know how your car handles and adjust.

5. not sure the effect of big brake kits; but it is safe to assume
that anytime you alter the braking system it will preform differently;
and if the computer is unable to learn big brakes then an adjustment
should be made so the system know what to do.

1. Kinda splitting hairs on that one aren't you? Doesn't allow you to
manuever but allows you to stay in control? Either way the idea behind ABS
is the three "S's" STOMP on the brakes, STAY on the brakes STEER the car.
" The IIHS report, issued December 10, 1996, notes that in single-vehicle
accidents, cars with antilock brakes are as much as 44% more likely to
produce fatalities than are cars without the antilock system. " Taken from
this website http://www.racingschools.com/tips/abs.shtml

2. Thank you for saying exactly what I said, the OP never (at least not
from what I read) stated why he wanted to unhook his ABS, maybe it was for
this type of event?

3. See elsewhere in this thread, I explained it more clearly. The way I
wrote it was not how I intended to say it. The ABS engages, not necessarily
the brakes...the brakes may not engage for a full second after hitting a
bump which can be dangerous.

4. Again, not for everyone. I seem to recall a magazine listing this as
the #1 mod they'd do on a WRX if they were going to race it however.

5. Show me the software that can effectively make this change and I'm all
over it. I don't think it exists, if it did, everyone that auto-x's would
utilizing a computer to manipulate their abs system in a manner that they
feel comfortable with. (Similar to how engine management is used to
optimize the fuel/ignition/boost/etc... to extract extra power) Seriously,
if someone came up with this type of software, I think you could make LOTS
AND LOTS of money from racers.

 

[CompUser]

5. Show me the software that can effectively make this change and I'm all
over it. I don't think it exists, if it did, everyone that auto-x's would
utilizing a computer to manipulate their abs system in a manner that they
feel comfortable with. (Similar to how engine management is used to
optimize the fuel/ignition/boost/etc... to extract extra power) Seriously,
if someone came up with this type of software, I think you could make LOTS
AND LOTS of money from racers.

Lol...check with Bosch, they did Subaru's ABS.

 

[iksalama]

Lol...check with Bosch, they did Subaru's ABS.

Yeah....like bosch is going to give out its (most likely) proprietary ABS
software to the general public, seems like a lawsuit waiting to happen there
(BTW, I did contact them, they won't give it out). I'm not saying the
software for the ABS can't be reflashed back to OEM specs by a subaru
dealer, but that won't help the big brake situation.

 

[CompUser]

I'm not saying the
software for the ABS can't be reflashed back to OEM specs by a subaru
dealer, but that won't help the big brake situation.

Already been done.