team3s            Monday, January 17 2000            Volume 01 : Number 028




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Date: Sun, 16 Jan 2000 21:26:14 EST
From: Topofwrld1@aol.com
Subject: Re: Team3S: Question about ABS

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In a message dated 01/16/2000 4:52:07 AM Mountain Standard Time,
robby@freesurf.ch writes:

<<
> ABS is dangereous on snow or dirt. the stopping distances are doubled to
> quadrupled, compared to a skilled driver.

No, our tests and my snow- and ice driving experience over all this years
here in the Alps tell a different story. Oh, by the way, even with ABS
activated you can still control the pressure force you give with the foot.
ABS is an emergency aiding braking system.
  >>

Lots of interesting discussion on ABS.  On very steep loose dirt or shale
slopes my Dodge (well..er...ummm. Dodge Durango), I am standing on my brakes
at about 2 mph and it feels that it will not stop. These are trails that
don't get the same panic reaction in my Dodge Ramcharger or Jeep Cherokee.

Could this apparent problem be caused by the ABS sensing the wheels are going
very slow and not allowing them to lock up?  A variation of this happened on
super glare ice in my Stealth.  The ABS did not kick in. I think the ABS
thought I was stopped because all wheels locked at the same time so it didn't
activate. I don't see the Stealth situtation as a hazard as nothing would
have made much difference.

My friend's Range Rover has an off-road setting for his ABS but I don't know
what it does. Any thoughts on the potential for this kind of hazard with ABS?

Dennis


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Date: Sun, 16 Jan 2000 22:02:01 -0800
From: "Murat Okcuoglu" <murat@dellnet.com>
Subject: Re: Team3S: Question about ABS

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> I mostly disagree on this topics ! Or do you think the people in DTM and
> other circle track events are that bad drivers so they installed ABS ?


Roger and others,

This is a very controversial topic. I respect your opinion. My opinion is
based on my experience and the feedback I got from many ABS engineers. I
have been working for the automotive industry for the last 15 years. I did
test ABS on all major manufacturers test tracks along with their test
drivers. Every year, I spend weeks in test tracks in arctic circle to
perfect ABS tuning.
It is a tool useful for many but not all drivers. It also depends on the
circumstances. if one is going to work early in the morning before
completely awake or coming off a bar late at night, one better should have
ABS. on the track or concentrated driving, I prefer not to use ABS.

For the humps, try going over a nice hill, the ones where you feel
weightless for a moment. At that instant, you have no brakes for almost a
second. there is not much ABS can do to distinguish under the circumstances.
It is terrible and dangerous, but as with all automotive systems, ABS is a
compromise.

I will tell you about my opinion on airbags, on a different occasion.



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Date: Sun, 16 Jan 2000 22:05:26 -0800
From: "Murat Okcuoglu" <murat@dellnet.com>
Subject: Re: Team3S: Question about ABS

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> Could this apparent problem be caused by the ABS sensing the wheels are
going
> very slow and not allowing them to lock up?  A variation of this happened
on
> super glare ice in my Stealth.  The ABS did not kick in. I think the ABS
> thought I was stopped because all wheels locked at the same time so it
didn't
> activate. I don't see the Stealth situtation as a hazard as nothing would
> have made much difference.
>
> My friend's Range Rover has an off-road setting for his ABS but I don't
know
> what it does. Any thoughts on the potential for this kind of hazard with
ABS?
>

The mechanics of effective braking on loose surfaces such as dirt or snow
requires wheel lockup and subsequent collection of loose material in front
of the tire. ABS does not allow this to happen, decreasing braking
efficiency.
again,. ABS tuning is a compromise, to work acceptably under all conditions.



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Date: Mon, 17 Jan 2000 00:55:58 +0100
From: lehir@genesiscom.ch (Genesiscon Lehir)
Subject: RE: Team3S: Question about ABS

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Hello everyone....

>>I mostly disagree on this topics !

I'm afraid I disagree with you on on that one.....:-)

>> Or do you think the people in DTM and
>>other circle track events are that bad drivers so they installed ABS ?

Well, there are a LOT of different ABS....and some are better than others...
and....F1 drivers do NOT use ABS.....so....

I do NOT know about the one in the Mitsu 3000, but I know the '92
RT/TT...and it SUCKS...

>>In 80% of the cases even the most experienced driver caused the wheels to
>>lock up.

Not a real problem if the driver immediately releases the pressure just
BELOW the lock point.

>> At this point he looses against ABS.

As said before, it depends WHICH ABS...

>> We made so many tests during our driving and racing schools and only
>>the M3 we had came pretty close to the braking distance like ABS did.

I did several tests at TCS (touring club Suisse), and I can outbrake a LOT
of 1st gen ABS...
Like in my Toyota Supra Turbo, Celica GT4, Subaru SVX.(I do not have these
cars anymore)
I can match my ABS in my 300 ZX TT (still have it)..

These tests were made on a plastic surface simulating heavy rain...

>> With more and more experience I was able
>>not to lock up the wheels but with a lot of concentration.

That's a good point....without ABS, you need a LOT of concentration.

>> And what if yo uhave to brake and turn the lane at the same time because
a child jump >>onto the street ?

Well, depends how you drive....(and, BTW, I've been in your car....you drive
better than that....:-)

>> Without ABS you gonna loose your end and our tests showed that
>>the (dummy) child got hit by the end of the car. Not with ABS !

for an average driver, or with an improper technique...maybe.....but
otherwise....

>>You know what happens when two wheels are on slippery road and the others
on
>>dry.

Yup. I know ;-)

>> Now a racing driver does this every day but not we "normal"
>>humans. I had this situation in rain and had hydroplaning on one side when
I
>>had to do the emergency braking. The ABS did the perfect job and I just
had
>>to step onto the brakes as hard as I can (CDs flying around....) and was
>>able to concentrate for the steering wheel including looking in the
mirror.
>>Hey, we humans are not multitask compatible so this is why we develop such
>>things !

Agree, ABS can do that...BUT...it will INCREASE your stropping distance as
well...

Remember that nice G-forces analyst I have...

>>No, our tests and my snow- and ice driving experience over all this years
>>here in the Alps tell a different story.

Well.....I did a couple tests (normal procedure for me when I get a new
car), and the ABS in MY RT/TT (once again, yours might be better) is
AWFUL.....

>>ABS is an emergency aiding braking system.

Yes, but......I simply HATE to have an "aid" that will more than double my
stopping distance on snow/ice.
It's performance is acceptable on dry pavement, and "about" ok on a wet
one...

>>Yes, the ones from 15 years ago did this. ABS is inactivated when the
wheels
>>do not turn anymore.

Well...I'm afraid my ABS is 15 years old then...
and the fact that my ABS is governed by the wheel with the LEAST traction
makes me think it's quite an old design, indeed.

>>Oh, it safed my front also at 20mph in snow as I was able to make a turn
in
>>snow with pushing the pedal :-)

ABS will ALWAYS allow you to TURN...this is not the point...NOT breaking at
all
allows you to turn as well.....point is....you MAY be able to steer without
thinking about the panic stop....BUT....you'll need a LONGER distance to
stop. And IMHO, TWICE the distance is NOT acceptable....

> my personal opinion after 15 years of vehicle dynamics experience.
> to answer your question, even if the vehicle is on a straight line, tire
> lock up will let the tail fo sideways. so, ABS is needed regardless of
> steering wheel position (for ordinary drivers)

>>Yep, I totally agree.

Me too...but.....if you know what you're doing....

In __MY__ case...when there's snow....the ABS fuse is.....missing..

Just a clarification....I'm not telling that eveyone should disable their
ABS...
In __MY__ case, I do the following

DRY : ABS : ON
WET : ABS : ON
SNOW: ABS : OFF (and I got that nice light to remind me it's off)

and....I practiced NOT locking my tires a many many many times...and I know
how to do it.

Henri..

Crazy Swiss driving on snow....



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Date: Mon, 17 Jan 2000 05:24:36 -0600
From: Matt Jannusch <MAJ@BigCharts.com>
Subject: RE: Team3S: Question about ABS

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> for an average driver, or with an improper technique...maybe.....
> but otherwise....

This is probably the central issue with ABS.  The problem is that everybody thinks they are better than average.  At what level do you need to be to be able to outbrake the ABS controller?  80%?  90%?

I agree that the ABS in Mitsubishi-built cars is a terrible system, however for a driver who doesn't normally drive at the limits and isn't familiar with how a car reacts in a skid it is still advanageous to have ABS.  I'd say that covers at least 90% of people out there, including about 50% of the people who *think* they are great drivers.

- -Matt
'95 3000GT Spyder VR4


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Date: Mon, 17 Jan 2000 14:06:03 +0100
From: "R.G." <robby@freesurf.ch>
Subject: Re: Team3S: Question about ABS

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I must agree with our ABS system being one of the worst....well I drive Z28 with ABS too and must say it is even worser. The 96+ Bosch 4-channel on the 3000GT is much better.

For racing, Formula 1 has ABS forbidden some years ago, WRC has also no ABS AFAIK, but BCR and older DTM had it. I for myself learned to drive under track conditions with ABS but almost never engaged it. But it helped for sure on bad situations :-)

Roger
93'3000GT TT


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Date: Mon, 17 Jan 2000 17:58:22 +0100
From: Matthews <matthews@wiesbaden.vistec.net>
Subject: Re: Team3S: Question about ABS

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Topofwrld1@aol.com wrote:
>
> Lots of interesting discussion on ABS.  On very steep loose dirt or shale
> slopes my Dodge (well..er...ummm. Dodge Durango), I am standing on my brakes
> at about 2 mph and it feels that it will not stop. These are rails that
> don't get the same panic reaction in my Dodge Ramcharger or Jeep Cherokee.
>
> Could this apparent problem be caused by the ABS sensing the wheels are going
> very slow and not allowing them to lock up?  A variation of this happened on
> super glare ice in my Stealth.  The ABS did not kick in. I think the ABS
> thought I was stopped because all wheels locked at the same time so it didn't
> activate.

Well, I'm not an ABS expert like some on the list, but here's my take on
the situation:

When you lock up the brakes, the ABS sees that your wheels have
decelerated too fast and releases brake pressure, but your tires don't
bite into the loose surface well enough to get spinning again before the
next ABS pulse.  Despite the fact that our cars have a G-force sensor,
all ABS knows about how your vehicle is interacting with the road is
from the wheels!  If it releases your brakes and your wheels don't start
spinning, then how is it to know that you're still moving?  In this case
you would have to manually pulse the brakes...


> My friend's Range Rover has an off-road setting for his ABS but I don't know
> what it does.

My guess is that the Range Rover's off-road setting would allow more
time between brake pulses, giving the reduced-traction surface time to
get the wheels turning again.

The ABS in our cars is surely optimized for what the manufacturer
considers normal driving environments for a high-performance GT.  Yes,
AWD gives our cars a heck of a lot more practicality over other cars in
its class, but just because you can out accelerate everything on the
road in adverse conditions doesn't mean you can control the speed any
better!

- --
Jim Matthews  3SI #30
Wiesbaden, Germany
http://rover.wiesbaden.vistec.net/~matthews/stealth.html


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Date: Mon, 17 Jan 2000 17:59:51 +0100
From: Matthews <matthews@wiesbaden.vistec.net>
Subject: Re: Team3S: Question about ABS

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Genesiscon Lehir wrote:
>
> I do NOT know about the one in the Mitsu 3000, but I know the '92
> RT/TT...and it SUCKS...

I assume that the system in the 3000GT is identical to that in the
Stealth, and I don't know if any improvements were made in the 2nd
gens.  In my car, straight line stopping distances with ABS seem
excessive, but when I have to steer, control is adequate.

Remember that we canNOT have four-phase ABS due to AWD!  So it is not
surprising that some cars (2WD) have more effective ABS than our cars.
Also keep in mind that many of us are running on tires that are perhaps
less than optimal for cold weather conditions.


> ABS will ALWAYS allow you to TURN...this is not the point...NOT breaking at
> all
> allows you to turn as well.....point is....you MAY be able to steer without
> thinking about the panic stop....BUT....you'll need a LONGER distance to
> stop. And IMHO, TWICE the distance is NOT acceptable....

This was the point of my original post.  ABS is indespendible for
steering control when at threshold braking.  BUT, when NOT turning, it
seems like a DISadvantage.  Hence the idea of a switch that is activated
by the steering angle sensor.  If lack of ABS and experience causes the
car to begin spinning, then a steering correction will reactivate ABS,
which will likely save your butt.

I think Roger's (and others') point is that in some situations (eg-
extreme traction difference between left and right side) the spin could
be so abrupt that it might be too late for the driver to react and
recover, even when ABS kicks in.


> Just a clarification....I'm not telling that eveyone should disable their
> ABS...
> In __MY__ case, I do the following
>
> DRY : ABS : ON
> WET : ABS : ON
> SNOW: ABS : OFF (and I got that nice light to remind me it's off)

Well, I don't think I'd go that far!  :-|  I think I'm pretty good at
avoiding lockup without ABS, too, but I'm not as good as ABS is
(especially in a panic situation)!  And in the Alps, there's no reset
button when you miss the curve and take a short cut down the mountain...

- --
Jim Matthews  3SI #30
Wiesbaden, Germany
http://rover.wiesbaden.vistec.net/~matthews/stealth.html


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Date: Mon, 17 Jan 2000 22:29:37 +0200
From: "Oleg-Telia" <Oleg@telia.lv>
Subject: Team3S: problem with brakes

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Maybe somebody has experienced the same problem.
The steering wheel starts to shake badly at speed between 40/70 mph when I'm
pushing brakes. When I bought this car (03.99), the problem already existed.
Old brake rotors were OK, but as I didn't know what to do, I bought new
(Stillen drilled). I changed brake pads (Metal matrix), brake lines and
brake fluid also. Nothing was changed! I have two wheel sets, everything is
perfectly balanced, so the matter isn't all mentioned.
What can be done? I am totally upset, what for do I need 0-60 in 4 seconds
if I don't have normal brakes?
Mitsu dealership can't can't find a matter, the diagnostics shows that
everything is OK.
Please help!

Olegs,
94'VR4
www.3000gt.lv
3si #0441





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End of team3s V1 #28
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