So You Think You're a Good Driver?

In article >, Scott en Aztlán wrote:
> On Sun, 15 Jan 2006 22:08:15 -0600,
> (Brent P) wrote:
>
>>These are from the 1975 MOTOR repair manual... covers a lot of makes and
>>models but manages to be better than a chiltons.
>
> The most telling portion is where they describe how to disable the
> system.
>
> I wonder if the 2035 edition of the MOTOR repair manual will have
> descriptions of how to disable the ABS, traction control, laser cruise
> control, blind spot sensors, and all the other gadgetry that today's
> cars come with?

I dunno if they are in business any more...

Mike T. wrote:
> >> I've also noticed an increase in the stopping distance required in snowy
> >> and icy conditions with consumer ABS brakes. It seems like the front
> >> wheels aren't braking, and there's no way to disable this dangerous
> >> feature while driving.

My Audis ('90 models) had a switch. It generally (exceptions noted
below) did not shorten anything by turning it off. I never met any
mere mortal who could outbrake the ABS on slick surfaces.

> >> If I apply additional pressure to the brake pedal
> >> after the ABS activates, the system should detect the inconsistency
> >> between pedal pressure and brake pressure, and increase the brake
> >> pressure.
> >
> > I'm sure there are plenty of corporate attorneys who can explain why the
> > engineers who design brake systems to work the way you want get spanked.

While I'm no *corporate* attorney, I can tell you this idea of yours is
just plain wrong. Increasing pressure after the ABS kicks in will only
lock the wheel and the tire will slide. In case you don't know (you
apparently don't), a sliding tire has lots less traction than a rolling
one, so that tire (or tires) will tend to *lead* the skid. If they're
the rear tires, you get to spin 180 degrees as well as not stopping -
or steering.

> NO! He's got a point. The ABS systems are biased to prevent wheel lockup,
> PERIOD, even if that means not applying enough braking force to bring the
> car to a stop quickly. The way they are programmed, you have steering
> ability, but very little STOPPING ability. Without ABS, a good driver can
> apply more braking force and keep the braking force close to the threshold
> where the wheels WOULD lock

You show only a scant understanding of threshold braking and even less
of ABS. ABS is only triggered when the wheels *do* lock, if only for
an instant; for less than a turn of the wheel. BMW's, f'rinstance, is
set for 25% slip. Threshold braking only takes place *before* any slip
occurs. Once a tire slides, it ain't 'threshold' any more, but it *is*
ABS time. Those of us who can and do threshold brake know the
difference. In short, if you're 'into' the ABS, you're *beyond*
threshold braking. If you switched it off, you'd simply be skidding -
and skidding locked wheels is *not* shorter or faster braking, in spite
of your firmly-held beliefs.

> . . . and if they do lock, a good driver can adjust for that.

It's called 'modulation' and the slicker the surface, the harder it is
for a threshold braker to unlock a wheel (by releasing *all four*,
including the three that might still have had traction) and get back to
the threshold of traction again. The electronics and hydraulics are
simply faster than we can be. ABS can be outbraked in only two
situations: good threshold braking in a straight line on dry pavement
and locking the wheels in low-traction particulate-piling stops (snow,
gravel, dirt). If you're on ice and the ABS doesn't stop you, you
weren't going to stop without it, either.

BTW, I noticed they were using a '90 BMW. Didn't *it* come with ABS?
Every one in the US did after 1986 ... including my current '88 535is.
--
C.R. Krieger
(Been there; drove that)

Dave in SD wrote:
> http://driving.timesonline.co.uk/art...973418,00.html
>
> Now try it without ABS, EBD, ESP, EBA ...
> Many drivers are blithely unaware of the hi-tech safety devices fitted
> to modern cars that silently keep them from danger. We put four
> volunteers in a 1990 car to see what happens when you take them away.
> James Luckhurst and Emma Smith of The Sunday Times stood well back.

Most safety features lull the idiot american into thinking it's ok to
drive crazy and make things worse!!!. The only way to stop the
incredible murdering on our highways is to lower speed limits and throw
the book at those who break the highway laws whether speeding, dui, red
light running or whatever. Next question.

On Mon, 16 Jan 2006, Motorhead Lawyer wrote:

> Mike T. wrote:

>>> I'm sure there are plenty of corporate attorneys who can explain why
>>> the engineers who design brake systems to work the way you want get
>>> spanked.

> While I'm no *corporate* attorney, I can tell you this idea of yours is
> just plain wrong.

Somewhere along the line the attribution got munged. That just plain wrong
idea was mine. If you say it's wrong, I believe you, but I'm still willing
to bet there are differences in ABS calibration for US (=NAFTA) vs.
rest-of-world markets that have more to do with liability suit prevention
than to do with brake optimisation.

In article ich.edu>, Daniel J. Stern wrote:
> On Mon, 16 Jan 2006, Motorhead Lawyer wrote:
>
>> Mike T. wrote:
>
>>>> I'm sure there are plenty of corporate attorneys who can explain why
>>>> the engineers who design brake systems to work the way you want get
>>>> spanked.
>
>> While I'm no *corporate* attorney, I can tell you this idea of yours is
>> just plain wrong.
>
> Somewhere along the line the attribution got munged. That just plain wrong
> idea was mine. If you say it's wrong, I believe you, but I'm still willing
> to bet there are differences in ABS calibration for US (=NAFTA) vs.
> rest-of-world markets that have more to do with liability suit prevention
> than to do with brake optimisation.

It seems somewhere along the way ABS was changed from shutting off at low
speed to always on. There had to be a reason why. The benefit of ABS in
infinite loop at low speed is about zero. If skidding at <5mph and
steering control is needed get off the brake. Infinite loop on the other
hand takes away the ability to just skid to a stop in a few feet instead
the car just keeps rolling along.

At these speeds ABS is causing rather preventing collisions. The only
trump card is the moron majority that might not know to get off the
brake pedal if they have to steer. Changing things for the moron
majority often means because of lawsuit potentional or judgements in
lawsuits.

On 12 Jan 2006 14:47:07 -0800, "Dave in SD" >
wrote:

>Now try it without ABS

Everyone has ABS. Buns and thighs too.

Hi!

"Scott en Aztlán" wrote:
> Holy Geez! I had no idea there were computers in cars way back in
> 1969!

Computer controlled fuel injection was first introduced
in 1967, in the VW 1600 LE/TLE.

Of course, "computer" meant something (almost, but not
entirely :-) different then.

Yours,
Erik.
--
"Never to be wrong, never to make promises that break
Is like singing in the wind, or writing on the surface of a lake"
-- Sting, "Be Still My Beating Heart"

Laura Bush murdered her boy friend wrote:
> Dave in SD wrote:
> > http://driving.timesonline.co.uk/art...973418,00.html
> >
> > Now try it without ABS, EBD, ESP, EBA ...
> > Many drivers are blithely unaware of the hi-tech safety devices fitted
> > to modern cars that silently keep them from danger. We put four
> > volunteers in a 1990 car to see what happens when you take them away.
> > James Luckhurst and Emma Smith of The Sunday Times stood well back.
>
> Most safety features lull the idiot american into thinking it's ok to
> drive crazy and make things worse!!!. The only way to stop the
> incredible murdering on our highways is to lower speed limits and throw
> the book at those who break the highway laws whether speeding, dui, red
> light running or whatever. Next question.

Can you be programmed to say anything else? Maybe simple household
tasks?

Dave Hogan

In article >,
Brent P > wrote:
>
>It seems somewhere along the way ABS was changed from shutting off at low
>speed to always on. There had to be a reason why. The benefit of ABS in
>infinite loop at low speed is about zero. If skidding at <5mph and
>steering control is needed get off the brake. Infinite loop on the other
>hand takes away the ability to just skid to a stop in a few feet instead
>the car just keeps rolling along.

Sounds more like a poorly engineered ABS system than a deliberate design
decision. Obviously at some point you WANT the tires to stop, and
furthermore at very slow speeds the input from the sensors becomes
less and less useful.
--
There's no such thing as a free lunch, but certain accounting practices can
result in a fully-depreciated one.