In late 1973
industry experienced a serious decline because of the Arab oil embargo and the accompanying rise in inflation. The boycott, which began on 19 October 1973
, caused turmoil in the world economy. Not only was the supply of gasoline greatly curtailed, causing lines at gasoline stations, but the price of petroleum went through the roof. The price of oil in December 1973
rocketed to between fourteen dollars and nineteen dollars per barrel, up from between two dollars and three dollars a year earlier. The increases presented the automobile
industry its greatest challenge since the Great Depression.
That Damn Bumper Law
The most obvious across-the-board changes in the 1973
US cars were the result of Motor Vehicle Safety Standard 571.215, best known as MVSS-215 or "that damn bumper law." Applying to all cars manufactured after September 1, 1972
, it required that they be test-crashed into a fixed barrier at 5 miles per hour in the front and 2.5 miles per hour in the rear. After the test there had to be no cracks in lamps or reflectors; hood, trunk and the doors had to operate normally; fuel, cooling and exhaust
systems were not to have leaks or constrictions, and all filler caps had to operate normally.
The Delco Enersorber
Though the speed seemed slow, the forces involved were not. For example, a 5300lb station wagon applied a force of around 26,000 pounds to its bumper mounts in the front impact. Since the "test mass" applied to the bumpers was the weight of the car itself, lighter cars had a progressively easier time meeting this standard. American Motors
scooped the industry by announcing well in advance that its new bumpers would qualify its cars for discounts in insurance premiums offered by the Allstate Insurance Company, an affiliate of Sears Roebuck. The SAAB 99
, we believe, was the first to have qualified, however as far as local US cars went, the honours went to American Motors
- courtesy of a self-restoring hydraulic "Enersorber" developed and sold to AMC by GM's Delco Products Division.
It was true that GM used the bumper mounts (two to a bumper) on their cars, but it was only at the front end, and American Motors offers them as options at the rear of its then new Hornet and Gremlin. So-equipped, they qualified for Allstate's maximum discount - 20 percent cheaper premiums for cars that could handle bumps at 5 miles per hour both front and rear with no damage at all - a much more severe requirement than MVSS-215. Like the SAAB
, the AMC 1973 Matador and Ambassador qualified for a 15 percent premium reduction by surviving the MVSS-215 test (with the lower-speed rear impact) with no visible damage. Not equipped with the self-restoring Delco bump-dampers, the AMC Javelin met MVSS-215 with some damage to body components and so qualified for Allstate's 10 percent insurance discount.
The AMC Buyer Protection Plan
Obviously all the 1973 cars met at least that minimum standard but, again, AMC gained a valuable public relations advantage by being the first to announce that its bumpers had been approved by Allstate. American Motors also expanded its simple and effective Buyer Protection Plan by offering buyers an extra-cost option extending coverage to two years or 24,000 miles, and also reimbursing the owner for food and lodging costs if hthey were more than 100 miles from home and their car has to be kept overnight at a dealer for service under the warranty. Among General Motors
cars, the MVSS-215 standard was met with the Delco Enersorbers on the front bumpers of all the big cars in its range of Chevrolet
marques and all the new intermediate-size cars from GM (those marques except Cadillac
Among the individual tricks employed were hinged and spring-loaded grilles on the Oldsmobiles that gave way when the bumper was pushed in and then snapped back into position - allowing the grille styling to be better integrated with the bumper - and a cast-urethane plastic front-end on Chevrolet's new luxury Chevelle model, the Laguna, which slid in and out in one unit with the bumper. Pontiac's comparable model, its Grand Am version of its intermediate-size Le Mans, had a hollow "rubber nose" that collapses along with the bumper. Except for station wagon models, the rear bumpers of Pontiac full-size, Le Mans and Grand Prix models were carried by spring steel buckling columns that defleced and then returned the bumper to the original position in the rear impact.
Corvette designer Zora Arkus-Duntov
The urethane-covered front bumper of the Chevrolet Corvette
had a unique attachment - two Omark bolts - special steel bolts which were extruded through dies to absorb energy when the bumper was struck. This worked so well at 5mph, said Corvette designer Zora Arkus-Duntov, that they tried it again at 7mph. "The result was disastrous," said a rueful Zora. Other GM cars, the sporty models (Camaro
and Firebird), compacts (Nova, Ventura and Oldsmobile's new Omega) and sub-compact (Vega), used stronger bumpers with heavier mounts to meet the standard. These cost less initially but, of course, had to be replaced if they're heavily impacted. The same technique was used by Chrysler for all its cars, equipping them with massive bumpers and big rubber guards, where needed.
Ford was the only one of the four manufacturers to equip the front bumpers of all its cars with self-restoring impact-absorbing devices of common design. The device consisted of a steel ram shaped like an I-beam attached to the bumper, inserted into a rectangular steel case fixed to the car's frame. Between the ram and the case, and bonded to both, were two blocks of a special rubber compound which was placed in shear in an impact, then bounced the bumper back in place. Five different absorbers of this type were used on Ford cars, weighing from 12 to 19 pounds each. With the necessary rugged bumpers, the whole system added from 45 pounds (Pinto) to 130 pounds (Lincoln) to the front end of Ford Motor Company cars. Full-sized Fords and Mercurys also used absorbers for the mounts of the rear bumper. Generally GM was more successful than Ford or Chrysler in giving its big ars a clean, light look at the front end in spite of the new bumper standard. Ford models in particular had a "safety car" look.
The big GM cars were mildly facelifted; the '73 Buicks were now cleaner and arguably better looking. Completely new were the GM intermediate car bodies, which were refreshing in their flush, clean lines and absence of needless ornamentation. The new intermediates, or "A body" cars, were typical Bill Mitchell artistry - given very different lower body lines. The cleanest and arguably the most classic version, looking back today, was the Chevrolet Chevelle. Elegant flamboyance was expressed by Buick's Century, the renamed Skylark, with front fenders blending back into the flanks. The Olds Cutlass was shaped in a mechanistic manner, with individual fairings for the front and rear wheels, while the Pontiac Le Mans was the most outrageous with large bulges around the wheels.
Both Chevrolet and Pontiac had completely special "personal cars" built on the intermediate chassis, both freshly styled for '73. Pontiac's Grand Prix was a sharper, crisper edition of an already successful design, while Chev's Monte Carlo moved from blandness to extravagance with sweeping side lines that, much like the Buick Rivieras, marked Mitchell's design style. Both had formal roof lines with opera windows at the sides. A similar roof was grafted onto the normal lower bodies, with slightly longer nosepieces, to give Buick its new Regal model and Olds its Cutlass Supreme Colonnade Hardtop Coupe.
Ford changed the styling of the lower sheet metal of its big Ford and Mercury sedans, and also the roofline of its four-door models, but the change, and the difference between the two was anything but earthshaking. The Torino's grille was pushed back abruptly to leave clearance for the front bumper to move back. AMC's popular Hornet had a new, richer-looking front end, and Chrysler's intermediates had new front ends. Dodge's Charger intermediate offered Chrysler Corporation's most exciting-looking new addition, the Charger SE model with louvred rear quarter windows akin to Renault's R17 coupe.
The industry made a break from "styling" toward creative body design with more widespread use of "hatchback" coupe models. Hatchbacks were optional on the GM compacts: Chevy Nova, Pontiac Ventura and Olds Omega. Chrysler was caught out by the popularity of the hatchback, and so offered optional folding rear seats on the Valiant Duster and Dodge Sport (replacing the Demon), thus bringing back a feature it dropped on the Barracuda years earlier. Good-looking new optional wheels offered on the 1973 cars range from the very real to the very fake. The very real ones included forged aluminium wheels of authentic California racing style, optional on Ford Pintos, Mavericks and Mustangs and Mercury Comets, and a cast aluminium wheel of eight-inch rim width offered for the new Corvette. The very fake ones were the so-called polycast wheels, incredibly realistic cast urethane plastic inserts adhering to plain steel wheels. Used by Pontiac and Olds in 1972, they were offered in two styles by Chevrolet, designs so authentic most punters could not tell that they were fake.
Brake and Suspension Changes
Behind the wheels there were brake and suspension changes - Ford's third-generation sliding-caliper disc brake, with 12 instead of the previous 26 parts, moved from use on the Lincoln Mark IV to all the big Fords, Mercurys and Lincolns. Front-wheel disc brakes
were standard on all but the smallest and oldest models at all companies except American Motors. GM's new intermediates had modular iron steering knuckles with integral steering arms. Dodge and Plymouth intermediates had front torsion bars and crossmembers newly rubber-insulated from the main unit body in the interest of a plusher, quieter ride.
Both ride and handling gains, as well as longer mileage and better fuel economy, accounted for the much wider use of radial tyres
on the 1973 cars.
This was largely pioneered by the Ford Motor Company, which had radials as standard equipment for '73 on big Fords, Mercurys and Lincolns and optional on all other car lines. Radials were also optional on all American Motors cars and on the full-size Chryslers, Dodges and Plymouths. Their use at GM was highly selective. At Pontiac, for example, steel-belted radials were part of the Grand Am and Grand Prix SJ "packages" and optional on the Bonneville and Firebird - in each case combined with special body mounts and other suspension tuning touches to match the car to the much lower spring rate, hence lower ride frequency, of radials - some 500 to 600 Ibs-per-inch against 1100 to 1200 for bias-belted tyres, or at least aht is what Buick's chief engineer, Phil Bowser, claimed.
Steel-belted radials were standard on the Buick Riviera GS, which made it an astonishingly quiet and nimble big car on these tyres. They were also optional on the Buick Century Gran Sport and the Electra. Radial tyres
were an integral part of the Oldsmobile Cutlass four-door sedan, with high-backed reclining seats, T console, restrained trim and steering-column headlight dimmer lever, motoring journalists believed the car to be heavily influenced by the Opel Diplomat. At Chevy the radials were standard on the Corvette, optional on the Vega and part of the Monte Carlo Model S package. Chevrolet attempted to get handling of Mercedes-Benz quality by increasing the front caster angle and adding a steering damper. It did make their cars handle much better than previous versions, but it was a long way from being a Mercedes-Benz.
Exhaust Gas Recirculation
And as if the safety and bumper regulations for 1973 were not enough of a headache for Detroit, there was a new Federal standard for oxides of nitrogen of 3 grams per mile. The same standard applied in 1972 in California, but it was measured on a concentration basis instead of a new true mass or "bag" method, which had the effect of reducing the allowable NOx output by 50 percent. Prominent among the methods used to reduce NOx was exhaust
gas recirculation, or EGR. It used the exhaust
gas as a plentiful supply of an inert gas that could be metered into the engine's combustion chamber, along with the fresh charge of air and fuel, to reduce the peak burning temperature enough - as required - to keep the engine from generating too much NOx.
Most of the '73 cars used some form of EGR, which engineers admitted reduced fuel economy by 1 to 2 miles per gallon. Exceptions were the Pinto and some of the American Motors sixes. Some of the Chrysler V8 engines used a simple aperture in the floor of the intake manifold through which a volume of gas flowed constantly, varying In relation to the inlet manifold vacuum. On most other engines a vacuum-controlled valve metered the amount of EGR to suit the driving and emissions cycle conditions. The flow was maximum, said Chevrolet, while the car was cruising at speeds between 30 and 70 mph. "The very thing we're trying to do with EGR," said Buick's Al Thompson, "is to make the engine operation less efficient under certain conditions." Releasing hot exhaust
gas into the incoming charge seemed the wrong thing to do, but Thompson and other engineers were able to prove that it was not as bad as it seemed.
At its maximum the EGR flow was around 12 percent of the incoming charge (an increase of 50 to 70 percent from the 1972 California proportion). The blending of this amount of exhaust
gas of about 300 to 450°F. with a fresh charge of some 130°F. in the manifold raised the temperature of the air/fuel mixture by no more than about 10°F. as it entered the inlet ports. GM fitted its EGR-control valve in the manifold while Ford released the gas through an adaptor just below the carburettor. For Ford, the 1973 emissions qualification tests were even tougher than they are for the other makers, under the rules laid down by the US Environmental Protection Agency for re-testing of the engines after Ford and the EPA found that the original tests had been invalidated by many unauthorized changes to the engines while the tests were under way. The EPA did allow Ford to ship new cars to its dealers - but the dealers were not allowed to sell them until the testing had been completed.
Against the 1973 low-emissions background one car maker - Pontlac - somehow managed to bring out a new high-performance engine. Optional in the division's intermediate coupes, Grand Prix and Trans Am models, it was a Super Duty version of Pontlac's 455 CID (7450cc) V8. It had four-bolt main bearing caps, special forged rods and pistons, heavy-duty lubrication systems, high-speed valve train with big valves
, ports developed on a flow bench, and an 8.4 to one compression ratio. Capable of running to 6000rpm, it developed 310 (DIN) bhp at 4000 rpm, the highest rating among 1973 cars, and 390 lb.ft of torque at 3600rpm.
For 1973 More and more makers were following the lead of the Corvette by offering anti-theft alarm systems as factory options. FoMoCo cars could be equipped with a built-in system sensitive to tampering with the bonnet, trunk or any doors, signalling through a tiny electronic module. Chrysler installed an alarm that was an integral part of the car's wiring harness.