Saab 900 Engineering – Body and Interior

The month of 900 love continues!

The following is the first part of a multi-part series that’ll reproduce an Engineering brochure for the Saab 900. 1985Gripen has kindly supplied me with a PDF of the prochure so that I can share it here. This one’s of particular interest to me as it’s a 1985 brochure and I’ll be picking up a 1985 Saab 900 tomorrow.

Those of you that are interested should also note that Wulf has a 1986 version of a similar publication at his SaabMedia website.

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Saab 900 Engineering

Body and Interior

The saloon’s styling is pleasing enough in the flesh and the boot space is truly enormous. One is always immediately impressed by any Saab’s excellent seats, the overall levels of finish, and the sure stability the cars possess once you are on the road… (AUTOCAR. GREAT BRITAIN)

The objective of the designer entrusted with the task of styling a product is obviously to produce an attractive end result. But the task of a car designer is not confined to producing elegant bodies and interiors. He must take into account a long succession of factors, many of which may appear to be incompatible.

A car primarily must be comfortable, practical and safe. It is these characteristics that determine the shape and appearance. But it should preferably not be apparent that the end product is a compromise, and one of the designer’s duties is thus to find the styling which gives the car its own unmistakable identity.

Saab 900 Airflow The designer must also adjust the basic shape of the car and any projecting components, so that the air flow will be deflected with the minimum possible turbulence. Sharp edges and protrusions give rise to turbulence and increase the fuel consumption of the car. This is illustrated by the fact that, at as low a road speed as 35 mph, more energy is necessary to overcome the air resistance (drag) than to overcome the mechanical losses in the drive train and tires. And tests on cars in the same size and performance class as the Saab 900 demonstrate that, by reducing the drag coefficient from 0.5 to 0.4, the fuel consumption on mixed cycle driving will be reduced by about 10%. The drag coefficient can be regarded as a “quality factor” for the shape of the car.

But the problem is not confined to achieving the lowest possible drag in the direction of travel. Consideration must also be given to the effect of the optimization of shape on the road behaviour and the directional stability in a blustery cross-wind, for instance.

At high speeds, the flow of air over the car may give rise to significant lifting forces (lift) at the rear wheels, which will impair the roadholding. If the car is also to have good directional stability at high speeds and in strong cross-winds, the loads on the wheels must be sufficiently and consistently high. The designers must therefore strike the best balance between drag and lift.

Other areas which must be studied are ventilation and air conditioning, dirt deposits on the windows, size and location of the cooling air intake and turbulence and spread of the exhaust gases behind the car.

During a series of full-scale wind-tunnel tests, Saab designers have gradually adjusted the basic design of the 900 body, in a step-by-step procedure, culminating in the present optimized shape. It was thus a compromise which struck the best possible balance between comfort, safety, appearance and low air resistance.

Saab 900 engineering Saab 900 engineering

Click either image to enlarge.

The cars of tomorrow will be the result of compromises to an even greater extent, in order to satisfy the demands which cannot readily be combined in any one car. Space, comfort and collision safety favour big cars. Our congested roads, economy and conservation of raw materials favour the small car. But roomy, safe and elegant cars can undoubtedly be built within limited external confines, as demonstrated by Saab with the 900 series.

Seldom has as advanced a car as the Saab 900 gained acceptance on the market in so short a space of time. And seldom has a new car received such widespread acclaim from the press and motoring public.

Particularly the Turbo. Autosport in Canada wrote: “It is difficult to put into words the charm and fascination of this remarkable car. As a combination of performance, refinement, and fuel economy, it stands alone, and the integrity of its engineering and the quality of its finish are second to none. If you were to conclude from the above that this is just about the best motor car which is at present being made, anywhere, you wouldn’t be far wrong.’

When the largest German automotive magazine “Auto, Motor und Sport” arranged a referendum on the “World’s best cars” in 1981, its readers voted the Saab 900 Turbo the undisputed winner in the category of imported cars up to 2.5 litres. In 1982 and 1983, the readers again voted the Saab Turbo this same honour, with Saab receiving almost 50% of all votes tabulated.

Saab 900 award The prestigious U.S. motoring journal, Road & Track, recently gave the seven members of its staff who normally test cars the assignment of selecting the l0 Best Cars for the Eighties. In the category “Best Sport Sedan’, the team was unanimous in picking the Saab 900 Turbo as number one.

And the American motoring magazine, Car & Driver summarized a Saab 900 test as follows: “If we had to pick one target at which to aim the sedan of tomorrow, this would be it…’

The “prototype for tomorrow has been developed further in several respects since this summary was written. The engine, front suspension details, luggage compartment and interior have been modified. The car has gradually become even more economical, comfortable and pratical to drive and own. And Saab has also launched an alternative to the hatchback – the Saab 900 4-door Sedan

The sedan models are intended for motorists who prefer a more traditional type of body. From the l98l model, the Saab 900 series is available with two types of body – with three or four doors. Three levels of luxury are also available – the 900, 900 S and Turbo.

Saab 900 engineering

To combine styling and utility under the pressure of strict technical and economic limitations is also a difficult task. But Saab designers are considered to have succeeded very well with the 900 series.

The overall impression is not broken up by improvisations and “stuck-on extras”. The Saab 900 is far more spacious inside than its outside would suggest. The fact that functional considerations have been given priority is also responsible for the Saab 900 being an exceptionally well-planned car which is practical down to the smallest details.

The deeply-curved windshield and the absence of sharp bodywork corners which induce turbulence have jointly reduced the wind noise to an exceptionally low value. A ridge forward of the sunroof (fitted as standard on certain models) and the curved windshield which deflects the air to the side both contribute to the wind noise being low, even when the car is driven at high speed with the sunroof open.

When Saab designed the hatchback model, one of the aims was that the rear window should be self-cleaning. Tests under the worst conceivable road conditions have demonstrated how successfully this aim has been achieved. The air flowing along the window forms a “curtain” between the glass and the dirt thrown up from the road.

In road racing, many car manufacturers have long experimented with spoilers fitted to the body to increase the top speed and improve the road behaviour. The shape and location of the spoiler must be very carefully designed and tested. Fitting a spoiler as an afterthought will not automatically produce better roadholding. The Saab 900 is fitted with a front spoiler which helps to reduce the fuel consumption.

The 3-door Turbo models are fitted with a large front spoiler and a rear spoiler as standard equipment.

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9 Comments

  1. Suppose this begs the question..why is the MY08 hood shaped the way it is?

    The semi-circular rise in it doesn’t appear to server a purpose and is downright distasteful.

    Good thing the other style queues are more attractive. The front end does have what appear to be unnecessarily sharp edges though hard to say the effect on aerodynamics.

  2. …thats whats being said Jeff but there’s very little aero-x in this.

    On looking again at it, i’ve just noticed the hood (on the aero-x), but its subtle and blends in well with its lines.

    Not so on the 9-3. If/when i buy one i can live with it but i still think its a crude interpretation.

  3. Saab bragged a lot about it’s aerodynamics on the 900 3-door over the years.
    An intresting thing in my fluid dynamcs university course was that the 900 was shown as an example of worst possible back-end design. The slope of the hatch was hitting exactly the slope for worst wortex and drag. Had it only been a little bit less or more slope, it would have been much better. The Turbo’s wing was shown as an example on how to rescue high speed stability on a poor aerodynamic design… To comfort Saab, the Porsche 911 was the second example…. 😉

  4. Erik, that’s right. We used vehicles as examples in my fluid/aero dynamics course and found similar things.

    Can’t comment on the 900 though as we didn’t test. It doesn’t appear to have very good aero-dyn characteristics. Kind of puts the lie to the “born from jets” moniker.

    Even the MY08 9-3 doesn’t appear to have the characteristics to slip through the air like it should. With everyone talking about fuel consumption, i find it interesting no one appears to have brought this up as an issue.

  5. Actually, a slight correction: this is the Engineering Features book for the 1983 SAAB 900, not the 1985. The brochure Swade published parts of in an earlier post was indeed the sales brochure for the 1985 model year, but the details in the Engineering Features book referenced in this post is for the 8-valve 1983 model (the 16-valve came out in 1985, at least in the States).

  6. Craig, I think that cars have gotten to the point aerodynamically where the difference between a coefficient-of-drag of 0.28 and 0.29 is not enough to see much of a fuel economy gain. I saw it pointed out by an automotive journalist that because all the car companies were going for the best overall aerodynamics that cars were beginning to all look very similar in shape. That’s a downside.

    If it were up to me I’d rather drive a C900 with a drag coefficient of 0.34 than an ’08 9³ Sport Sedan with a drag coefficient of 0.28 if only based on aesthetics…

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