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AN EXPLANATION, IN PLAIN ENGLISH, OF THE
MOST TECHNOLOGICALLY ADVANCED CAR OF THE 1980'S.
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“Saab doesn’t build automobiles— Saab builds Saabs,
which are a highly original and highly logical answer to at
least one facet of the human transportation problem’—
Car & Driver.
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SAAB ENGINEERS ADDRESS PROBLEMS, NOT MARKETING FASHIONS.
The first Saab automobiles
weren't designed by automotive
engineers working with decades of
tradition behind them. They were
designed by the aeronautical
engineers of Svenska Aeroplan
AB, men who had taken part in the
enormous growth of aircraft
technology during World War II.
When they turned their atten-
tion to building an automobile, they
went at it in the same way they
approached a new aircraft design.
Without preconceptions or preju-
dices, seeking out answers to the
problems posed by Nature.
For more than 30 years, Saab
has maintained that approach to
the problems of automobile trans-
portation. Ever since 1950, we've
heard other people call our cars
“revolutionary”, “innovative” and
“radically different” We've thought
of them simply as commonsense
answers to real problems.
FUN IS NOT AN ACCIDENT.
Even though they weren't
automotive engineers, those first
Saab planners were automotive
enthusiasts. When they designed
a car, it wasn’t enough for it to be
safe and strong, economical and
comfortable. It also had to be fun
to drive.
From the beginning, Saab's
customers included a dedicated
corps of enthusiasts who raced
and rallied all over Europe, North
America and Africa.
That driving pleasure is the
end result of Saab’s insistence on
solving real-world problems
rather than jumping at momentary
marketing opportunities.
Most other auto manufacturers
seem to go at design the other way
around. First they see a change
in the market; then they tell their
designers, “Hey, we need a new
sports coupe!” Or station wagon.
Or sedan. That approach imposes
a whole set of prejudices and pre-
conceptions on the designer about
how the finished car will look and
what compromises will have to be
made.
Saab engineers begin with a
set of problems:
—How do we build a reliable
and economical engine that’s
powerful and responsive
enough to meet the demands
of modern highway driving?
—How do we put that power and
responsiveness in the driver's
hands, so that he can control
the car easily and positively?
—How can we build a cockpit
that will keep that driver
relaxed and alert enough to
use those controls effectively?
—How can we transmit the
engine’s power to the ground
in a way that permits the
driver to avoid accidents
in almost any conditions of
weather or traffic?
—How can we build a car strong
enough to help protect its
occupants when a crash is
unavoidable?
—How can we create an interior
that will accommodate four
adults comfortably and that
has expandable luggage space,
without also dictating an
oversized exterior?
The validity of Saab’s problem-
oriented approach has been proven
not only by thousands of Saab
owners but by the frequency
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with which our “revolutionary” and
“radically different” ideas are
eventually copied by other manu-
facturers. In the 19 few cars
had front-wheel drive and little
attention was given to aerodynamic
bodies. In the early 1970s, the
hatchback coupe was a new and
strange body style. All of those
early innovations have become
commonplace and today other
manufacturers are beginning to
follow Saab’s lead in the turb
charging of passenger car engines.
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HOW DO WE BUILD A RELIABLE AND ECONOMICAL ENGINE
THAT'S POWERFUL AND RESPONSIVE ENOUGH TO MEET THE DEMANDS
OF MODERN HIGHWAY DRIVING?
Developing both power and
economy in a single engine is the
kind of engineering problem that,
on the face of it, looks unanswer-
able.
Because, traditionally, you
make an engine more powerful by
adding cylinders or enlarging them
and more economical by taking
away cylinders or making them
smaller. Obviously, you can’t both
increase and decrease an engine’s
displacement, so a different
approach is called for.
In fact, the problem had to be
approached from several different
ways before Saab engineers were
satisfied that they had achieved the
balance of performance, economy
and reliability that they sought.
—All Saab 900 models share a
basic powerplant. This is a
relatively small engine that is
lightweight and extremely
efficient at deriving the
maximum benefit from the
fuel it uses. It’s an engine that
is flexible enough to cope easily
with the driving requirements
of the majority of drivers.
—For those other drivers, the
minority who want or need an
outstanding high-performance
vehicle, Saab engineers have
developed a sophisticated
turbocharging unit which
boosts the engine’s maximum
power to 135 horsepower from
the basic unit's 110.
—All Saab 900s have an ad-
vanced aerodynamic body that
minimizes air resistance and
uses the engine power more
efficiently. Although this isn’t
truly a problem relating to
engine design, it does illustrate
the integration of all facets of
Saab design. On the one hand,
the aerodynamic body shell
enhances the engine’s function.
On the other hand, the engine is
canted at a 45-degree angle, to
allow the deep slope of the hood.
THE 900 POWERPLANT.
Although the Turbo is our
“high-performance” model, all of
the Saab 900s are exciting cars. In
designing even our most modest
car, performance was an important
consideration. For one thing, we're
automotive enthusiasts and we
believe that a car should be fun to
drive.
There's an even more impor-
tant consideration regarding a car's
ability to perform, though. That’s
safety. We were early pioneers in
the field of active safety and we
recognized quickly that part of
staying sate ties in being able to
get out of trouble’s way. When a
driver needs to go into an oncom-
ing lane to pass slow traffic, he
wants to be exposed for the
shortest possible time. When he
comes onto a highway, he wants to
get up to cruising speed as quickly
as possible.
The engine which all current
Saabs share is a four-cylinder, two-
litre, single overhead camshaft,
fuel-injected powerplant which, in
its normally aspirated (non-turbo-
charged) version, develops 110
horsepower and 119 foot pounds
of torque.
The size of the engine—two
litres divided among four
cylinders—is very flexible. It’s a
small enough engine to use fuel
conservatively but large enough
to develop plenty of torque for
moving the Saab 900 from a full
stop, or up a hill under a load.
To keep the engine weight
down, the cylinder head, camshaft
cover and intake manifold are all
cast in a lightweight aluminum
alloy.
Mounting the camshaft over-
head, directly above the valves,
permits much more precise timing
of valve operations than previous
systems did, with the complicated
arrangements of pushrods and
rocker arms. It also reduces the
weight of the engine and the
number of moving parts.
All Saab 900s use the Bosch
continuous-injection fuel injection
system, instead of conventional
carburetors. The advantage of fuel
injection is that it maintains the
optimum mixture of fuel and air
at all speeds, so that the engine
operates efficiently throughout its
entire range.
FOR THE DEMANDING
MINORITY:
TURBOCHARGING.
The 900 series engine easily
satisfies the needs of the great
majority of drivers. The handful
who remain are the genuine high-
performance enthusiasts. Saab
takes the needs of that minority
very, very seriously.
The evidence of our concern
is the Saab 900 Turbo.
We introduced turbocharging
in our cars in 1978. This year, with
the introduction of our new Auto-
matic Performance Control (APC)
system, Saab offers the most
efficient turbocharged gasoline
engine available in a passenger car.
Turbocharging lets the driver
get power from his car that’s equiv-
alent to the power of a six-cylinder
or V-8 engine, when he wants it.
When there’s no demand for high
erformance, the Saab Turbo
ehaves like a four-cylinder car,
giving you all of the fuel economy
of the smaller engine.
Of course, a larger engine
would give you the same sparkling
erformance as the Saab Turbo,
ut most of the time it would be
wasteful. Even enthusiastic drivers
spend most of their driving time
at low speeds and get to use the
power of their engines only about
15 percent of the time. At low
speeds, a six-cylinder or V-8 engine
is burning more fuel than it needs
to move the car.
The turbocharger, on the other
hand, makes the same power
available without adding weight
to the car or increasing the fuel
demand at low speeds. By adding
a turbocharger to the Saab 900
engine, we boosted horsepower
from 110 to 135 and increased
maximum torque from 119 foot
pounds to 172 foot pounds. Thanks
to the new APC system, the Turbo
can run comfortably on low-octane
fuels, and even at 87 octane will
develop 160 foot pounds of torque.
As exotic and complicated as
turbocharging may sound, it’s
really a simple, commonsense idea.
Even before Saab developed the
system that makes it practical on
passenger cars, turbocharging was
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SAAB 900 S
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used successfully on aircraft,
trucks and racing cars.
In fact, the basic idea has been
around for most of this century.
The principle was patented in
Zurich in 1905 by Dr. Alfred Buchi.
MAKING ITALL WORK.
A turbocharger is basically two
wheels connected by a shaft. One
of the wheels, the turbo turbine, is
spun at high speeds by heated
exhaust gases leaving the engine.
The turbine spins the compressor,
the second wheel. The compressor
pressurizes fresh air going into the
cylinders for combustion.
Because the engine is now
getting more air forced into it, it’s
capable of burning more fuel. That
allows it to produce much more
power than a normally-aspirated
(unturbocharged) engine of the
same size would produce.
Until Saab’s development of
the wastegate, the turbocharger
was only usable on engines which
would operate at high speeds and
high internal pressures most of the
time. The wastegate, or charging
pressure control valve, is opened
when pressures in the intake
manifold reach a predetermined
level. When it opens, it bypasses
a portion of the engine exhaust
gases around the turbine, reducing
the turbo boost.
The wastegate protects the
engine from being damaged by
the high pressures which the
turbocharger develops. Thanks to
that protection, Saab engineers
were able to design a very small
turbocharger, lightweight enough to
respond to normal driving speeds.
The Saab turbocharger begins
operation at engine speeds between
1,500 and 2,000 revolutions per
minute (rpm). By the time
engine is turning at 3,000 rpm, still
a moderate engine speed, horse-
power has been boosted by a third
just by the action of the turbo unit.
At 4,800 rpm, the Saab Turbo
hits its peak horsepower of 135.
AUTOMATIC
PERFORMANCE CONTROL.
For 1983, all Saab Turbos are
equipped with a new APC system.
The APC monitors the octane
rating of the gasoline used and
adjusts the turbo boost to take
advantage of it. It increases the
boost to get maximum use from
high-octane fuels, and decreases
it to protect the engine from
knocking due to low-octane fuels.
Octane rating is a measure of
the gasoline’s ability to withstand
compression in a mixture with air.
A 93 octane fuel can be safely
compressed farther than an 87
octane fuel.
An engine’s efficiency de-
pends largely on its compression
ratio. The greater the compression,
the more use it gets from its fuel.
But the danger of engine knock
also increases with pressure,
because a fuel that is compressed
too far can self-ignite in the
cylinder at the wrong moment.
Too much knock can severely
damage an engine.
Choosing a safe compression
ratio is especially critical in a turbo
engine, because the turbocharger
increases pressure when it’s in
operation. To prevent excessive
knock, most manufacturers
of turbo cars have opted for low
compression ratios and low
maximum turbo boosts. While
that may be safe, it isn’t efficient.
A boost setting that’s low
enough to protect the engine from
the lowest possible octane fuel
under the worst conditions is too
Electrical signal
from ignition system
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Saab’s new Automatic Performance Control (APC) system consists of: (D) a knock detector that
measures vibration in the engine; (2) a pressure sensor which monitors air pressure in the intake
manifold; (3) a solid-state electronic control unit which processes the information from the knock
detector and pressure sensor, and then operates (4) the solenoid valve, The solenoid valve contrls the
intake charge pressure according to the instructions from the control unit.
low to get the best use from your
gasoline.
Since the APC system pro-
vides comprehensive protection to
the engine regardless of the
octane rating of the gasoline, we’ve
been able to increase the Turbo’s
compression ratio from 7.2:1 to
8.5:1, making it the most efficient
gasoline turbocharged passenger
car available.
The system includes a knock
sensor, mounted on the outside of
the engine between cylinders two
and three; a pressure transducer on
the intake manifold; an electronic
control unit which balances signals
from the pressure transducer, the
knock detector and the ignition
system; and a solenoid valve which
opens and closes in response to
commands from the control unit.
If any part of the APC system
fails, the entire system stops
operating, and the turbocharger
functions as a conventional unit.
With the APC out of operation, the
turbo's fixed maximum boost is
low enough to ensure knock-free
operation with the worst grade of
gasoline until the APC system can
be repaired.
“
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HOW DO WE PUT THAT POWER
AND RESPONSIVENESS IN THE
DRIVER'S HANDS SO THAT HE CAN
CONTROL IT EASILY AND POSITIVELY?
The cockpit of the Saab 900 is
crisp, clean, functional.
From his seat, the driver has a
broad, uninterrupted view forward,
with the car’s instruments at the
lower edge of his peripheral vision.
The steering wheel is angled and
sized to come solidly to his hand.
And without taking his hand
from the wheel, he can reach the
switches for windshield wipers and
washer, turn signals and headlight
flasher/dimmer. The gearshift
lever is next to his right hip, within
easy reach, and the car’s pedals are
large enough for sure operation
even by heavily-booted feet.
Everything about the cockpit
works to give the driver a fast and
accurate flow of information and to
enable him to respond just as
quickly and accurately. This is a
work space designed for a driver
who has to be able to make fast
judgments and react quickly to
them. It’s a work space that bor-
rows a lot from aircraft design, as
a matter of fact.
Ergonomics, the technology of
the workplace, came of age in the
aircraft industry because pilots
have to be able to monitor lots of
different kinds of information and
respond quickly and surely. Some
of the leading scientists in this
new technology are employed by
Saab-Scania’s Aerospace Division,
and the application of their re-
search to our cars has been almost
immediate.
Many of the design features
of the Saab 900 resemble their
counterparts in Saab fighter jets
for just that reason. The deeply
curved windshield, for instance,
that moves the car’s “A” pillars
back behind the driver’s field of
vision.
Or the instrument cluster.
The instruments are designed and
located so that any sudden change
in the car is telegraphed to the
driver, even though he isn't looking
at the instruments at the moment.
First of all, they are large, round
gauges, with white figures and
orange pointers against a black
background. A sudden change of a
pointer’s position is much easier
for a driver to see quickly than a
change in a digital display. And
the instruments are clustered just
below the bottom visible edge of
the windshield, directly in front of
the driver, framed by the upper half
of the steering wheel.
The instruments are also set
deeply inside a curved control
panel, so that they’re protected
from glaring light that would make
The 900's cockpit is designed to give the driver cointl te control. Figure A shows the dashboard
with instruments display
at the bottom edge of the driver's vision and controls close at hand.
Figure B demonstrates “clustering” of controls by function; all of the starting controls (gearshift,
ignition lock and handbrake) ave located together at driver's right side. Figure C shows Saab’s new
tachometer with an indicator to show the most economical engine speeds.
them unreadable. That same curve
of the panel presents an array of
controls to the driver in a way that
puts them close to the steering
wheel, without a confusing cluster
of dissimilar functions.
One of the things that keep
it unconfusing is the grouping of
controls into zones. All of the
lighting controls, for instance, are
on the left side of the steering
column. The ones which will be
used frequently, directional signals
and the bright/dim switch, are ona
single stalk, while the on-off switch
for headlights and parking lights is
a recessed rotary switch.
All of the starting controls
(ignition switch, handbrake, and
gearshift lever) are located
together in the center console on
the driver’s right side.
To make sure that the flow of
information from outside the car is
as complete and easy to read as the
information from instruments, we
use windshield wipers which
sweep in an asymmetrical pattern,
to clear the broadest area possible.
The Saab 900's back-up lights
include not only lighting at the rear
of the car but side-guidance lamps
to help in parking or backing from
tight spaces. And indicator and
parking lamps are wrapped around
fenders for visibility through an arc
of at least 235 degrees.
The inside rear-view mirror
is adjustable for day or night driv-
ing, to keep glare out of the driver’s
eyes. And the large external
mirrors are adjustable from the
driver's seat.