Citroen DS 19 Cabrio, 1964

Citroen DS 19 Cabrio, 1964

The Citroën DS (also known as Déesse, or Goddess, after the punning initials in French) was an automobile produced by the French manufacturer Citroën between 1955 and 1975. Citroën sold nearly 1.5 million D-series during its 20 years of production.The DS is well-known for its futuristic, aerodynamic body design, and for its innovative technology (including its hydropneumatic self-leveling suspension system).

The DS advanced the achievable standards in terms of ride quality, roadholding, handling, and braking in an automobile. Automotive journalists of the time often noted that competitors took decades to adapt to the higher standards it set. The smooth, aerodynamic body lines gave the car a futuristic appearance. While it looked very unusual in 1955, public tastes appear to have caught up with the DS in the post-Ford Taurus/Audi 100 era.

Model history
After 18 years of development in secret as the successor to the venerable Traction Avant, the DS 19 was introduced on October 5, 1955 at the Paris Motor Show. The car's appearance and innovative engineering captured the imagination of the public and the automobile industry almost overnight. 743 orders were taken in the first 15 minutes of the show, and orders for the first day totalled 12,000.

Far from being just a fascinating technology in search of a purpose, contemporary journalists were effusive in noting how the DS dramatically pushed the envelope in the ride vs. handling compromise possible in a motor vehicle.

The high price tag, however, hurt general sales in a country still recovering from World War II 10 years earlier, and a submodel, the ID (another pun: in French, Idée, or Idea), was introduced in 1957 to appeal to more cost-conscious buyers. The ID shared the same body with the DS, but had more traditional features under the hood. It had no power steering (though this was added as an option later), and instead of the hydraulically controlled manual transmission and clutch, it had a conventional clutch and transmission. Interestingly, the first model series was called 11D, a clear reminder of the last model of the Traction Avant, the 11C. A station wagon variant, the ID Break, was introduced in 1958.

Outside of France, the car's radical and cosmopolitan design appealed to non-conformists. A United States advertisement summarised this selling point: "It takes a special person to drive a special car".

Throughout its model lifetime, the DS managed to remain ahead of its time. It featured power disc brakes, a hydropneumatic suspension including an automatic levelling system and variable ground clearance, power steering and a semi-automatic transmission. A fiberglass roof reduced weight transfer. Inboard front brakes (as well as an independent suspension) reduced unsprung weight. Different front and rear track widths and tire sizes reduced the understeer typical of front-engined and front-wheel drive cars.

Despite the rather leisurely acceleration afforded by its small four-cylinder engine, the DS was successful in motorsports like rallying, where sustained speeds on poor surfaces are paramount.

The DS came in third in the 1999 Car of the Century competition, recognizing the the world's most influential auto designs. Winner and second place went to the Ford Model T and the Mini. It placed fifth on Automobile Magazine "100 Coolest Cars" listing in 2005.

Technical innovations
Hydraulic system
The hydraulic system of the DS 19 was a revolution. Previously hydraulics had been restricted to use in brakes and power steering; the DS used them for the suspension, clutch and transmission. The later ID19 had manual steering and a simplified power braking system.

Suspension
At a time when few passenger vehicles had caught up with the four-wheel independent suspension of the Traction Avant, the application of the hydraulic system to the car's suspension system to provide true self-levelling was a stunning move. This application - 'hydropneumatic suspension' - was pioneered the year before on the rear of the top of range Traction Avant 15CV-H.

At first it was often described as air/oil suspension, since both elements played a key role.

Each wheel was connected not to a spring, but to a hydraulic suspension unit consisting of:
    * a sphere of about 12 cm in diameter containing pressurised nitrogen
    * a cylinder containing hydraulic fluid screwed to the suspension sphere
    * a piston inside the cylinder connected by levers to the suspension itself
    * a damper valve between the piston and the sphere

A membrane in the sphere prevented the nitrogen from escaping. The motion of the wheels translated to a motion of the piston, which acted on the oil in the nitrogen cushion and provided the spring effect. The damper valve took place of the shock absorber in conventional suspensions.

The hydraulic cylinder was fed with hydraulic fluid from the main pressure reservoir via a height corrector, a valve controlled by the mid-position of the anti-roll bar connected to the axle. If the suspension was too low, the height corrector introduced high-pressure fluid. If it was too high, it released fluid back to the fluid reservoir. In this manner, it maintained a constant height. A control in the cabin allowed the driver to select one of five heights:
    * normal riding height.
    * two slightly higher riding heights, for poor terrain.
    * two extreme positions for changing wheels.

The DS did not have a jack for lifting the car off the ground. Instead, the hydraulic system enabled wheel changes with the aid of a simple adjustable stand.

Source and reserve of pressure
The central part of the hydraulic system was the high pressure reservoir, which maintained a pressure of between 130 and 150 bar in two accumulators. These accumulators were very similar in construction to the suspension spheres. One was dedicated to the brakes, and the other ran the other hydraulic systems. Thus in case of a hydraulic failure (a surprisingly infrequent occurrence), the first indication would be that the steering became heavy, followed by the gearbox not working; only later would the brakes fail.

Hydraulic fluid
The original hydropneumatic system used a vegetable oil (LHV or liquide hydraulique végétale) similar to that used in other cars at the time. Very soon, Citroën changed to using a synthetic fluid (LHS or liquide hydraulique synthétique). Both of these had the disadvantage that they are hygroscopic, as is the case with most brake fluids. Disuse allows water to enter the hydraulic components causing deterioration and expensive maintenance work. The difficulty with hygroscopic hydraulic fluid was exacerbated in the DS/ID due to the extreme rise and fall in the fluid level in the reservoir, which went from nearly full to nearly empty when the suspension "got up" and the 6 accumulators in the system filled with fluid. With every "inhalation" of fresh moisture- (and dust-) laden air, the fluid absorbed more water. In August 1967, Citroën introduced a new mineral oil-based fluid LHM, or liquide hydraulique minérale. This fluid was much less aggressive on the system and it remains in use to the present day.

Briefly illegal in the United States (US federal law requires motor vehicle brake fluid to be red - an exception had to be granted to Citroën), LHM has since been adopted by manufacturers like Rolls-Royce, Jaguar, BMW, and Audi under different labels, like "Total," "Pentosin," and others.

LHM required completely different materials for the seals. Using either fluid in the incorrect system would completely destroy the hydraulic seals very quickly. To help avoid this problem, Citroën added a bright green dye to the LHM fluid and also painted all hydraulic elements bright green. The former LHS parts were painted black.

Several different hydraulic pumps were used. The DS used a seven-cylinder axial piston pump driven off two belts and delivering 175 bar of pressure. The ID19, with its simpler hydraulic system, had a single cylinder pump.

Gearbox and clutch
The mechanical aspects of the gearbox and clutch were completely conventional and the same elements were used in the ID 19.

The gear change control consisted of:
    * Hydraulic gear selector.
    * Clutch control. This was the most complicated part. The speed of engagement of the clutch was controlled by:
    * A centrifugal regulator, sensing engine rpm and driven off the camshaft by a belt
    * The position of the butterfly valve in the carburettor (i.e. the position of the accelerator)
    * The brake circuit: when the brake was pressed, the engine idle speed dropped to a rpm below the clutch engagement speed, thus preventing friction while stopped in gear at traffic lights. When the brake was released, the idle speed increased to the clutch dragging speed. The car would then "creep" much like automatic transmission cars. This drop in idle throttle position also caused the car to have more engine drag when the brakes were applied even before the car slowed to the idle speed in gear, preventing the engine from "pulling" against the brakes.

Impact on Citroën brand development
The 1955 DS in one stroke cemented the Citroën brand name as an automotive innovator. In fact, the DS caused such a huge sensation that Citroën was fearful future models would not be bold enough. Other than variations on the very basic 2 cylinder economy car Citroën 2CV, like the Citroën Ami, no new models were introduced from 1955 to 1970.

The DS was a large, expensive executive car and a downward brand extension was attempted, but without result. Throughout the late 1950s and 1960s Citroën developed many new vehicles for the very large market segments between the 2CV and the DS, occupied by vehicles like the Peugeot 403, Renault 16 and Ford Cortina. None made it to production. Either they had uneconomic build costs, or were ordinary "me too" cars, not up to the company's high standard of innovation. Because Citroën was owned by Michelin as a sort of research laboratory, such experimentation was possible. Citroën finally did introduce the clever Citroën GS in 1970, which sold a spectacular 2.5 million units.

DS in the US
While the DS was a hit in Europe, it seemed rather odd in the United States. Ostensibly a luxurious car, it did not have the basic features that buyers of that era expected to find on such a vehicle - fully automatic transmission, air conditioning, power windows and a reasonably powerful engine. The DS price point was similar to the contemporary Cadillac luxury car. Also, people at the time wanted only the newest models, which changed every year, like fashion, yet the DS appeared vaguely derivative of the 1950 Hudson Hornet step-down design.

Outdated US legislation also banned one of the car's more advanced features, aerodynamic headlamps, now common in US automobiles. Ultimately, 38,000 units were sold. The first year of the aerodynamic glass over the DS' headlights along with driving lights turned by the steering, was also the first year these features were outlawed in the US.

Design variations

The DS always maintained its size and shape, with easily removable, unstressed body panels, but certain design changes did occur.

A station wagon version was introduced in 1958. It was known by various names in different markets (Break in France, Safari and Familiale in the UK, Wagon in the US, and Citroën Australia used the terms Safari and Station-Wagon). It had a steel roof to support the standard roof rack.

In September 1962, the DS was restyled with a more aerodynamically efficient nose, better ventilation and other improvements. It retained the open two headlamp appearance, but was available with an optional set of driving lights mounted on the front fenders. In 1965 a luxury upgrade kit, the DS Pallas (after Greek goddess Pallas), was introduced. This included comfort features such as better noise insulation, leather upholstery and external trim embellishments.

In 1967, the DS and ID was again restyled. This version had a more streamlined headlamp design, giving the car a notably shark-like appearance. This design had four headlights under a smooth glass canopy, and the inner set swivelled with the steering wheel. This allowed the driver to see 'around' turns, especially valuable on twisting roads driven at high speed at night.

However, this feature was not allowed in the US at the time (see World Forum for Harmonization of Vehicle Regulations), so a version with four exposed headlights that did not swivel was made for the US market.

The station wagon edition, the Break (called the ID Safari on the UK market) and "Familiale", was also upgraded. The hydraulic fluid changed in all markets (except the US) to the technically superior LHM (Liquide Hydraulique Minérale).

Rarest and most collectible of all DS variants, a convertible was offered from 1958 until 1973. The convertibles were built in small series by French carrossier Henri Chapron, for the Citroën factory. In addition, Chapron also produced a few coupés, non-works convertibles and special sedans (DS Lorraine for instance).

DS engines
As with all French cars, the DS design was impacted by the tax horsepower system, which effectively mandated very small engines.

Unlike the Traction Avant predecessor, there was no top-of-range model with a powerful six cylinder engine. The DS was designed around an air cooled flat six based on the design of the 2 cylinder engine of the 2CV, similar to the motor in the Porsche 911. Technical issues forced this idea to be scrapped.

Thus, for such a modern car, the engine of the original DS 19 was also old-fashioned. It was derived from the engine of the 11CV Traction Avant (models 11B and 11C). It was an OHV four-cylinder engine with three main bearings and dry liners, and a bore of 78 mm and a stroke of 100 mm, giving a volumetric displacement of 1911 cc. The cylinder head had been reworked; the 11C had a reverse-flow cast iron cylinder head and generated 60 hp at 3800 rpm; by contrast, the DS 19 had an aluminium cross-flow head with hemispherical combustion chambers and generated 75 hp at 4500 rpm. Apart from these details, there was very little difference between the engines: even the locations of the cylinder head studs were the same, so that it was possible to put the cylinder head of a DS on a Traction Avant engine and run it.

Like the Traction Avant, the DS had the gearbox mounted in front of the engine, with the differential in between. Thus the DS is a really a mid engine front wheel drive car. It initially had a four-speed transmission and clutch, operated by a hydraulic controller. To change gears, the driver flicked a lever behind the steering wheel to the next position and eased-up on the accelerator pedal. The hydraulic controller disengaged the clutch, engaged the nominated gear, and re-engaged the clutch. Manual transmission control was a lower-cost option. The later and simpler ID19 also had the same gearbox and clutch, manually operated. In the 1970s a five-speed manual and 3-speed fully-automatic were introduced, in addition to the original four-speed unit.

The DS and ID powerplants evolved throughout its 20 year production life. The car was underpowered and faced constant mechanical changes to boost the performance of the four-cylinder engine. The initial 1911 cc 3 main bearing engine (carried forward from the Traction Avant) of the DS 19 was replaced in 1965 with the 1985 cc 5 bearing motor of the DS 19a (called DS20 from September 1969).

The DS 21 was also introduced for model year 1965. This was a 2175 cc, 5 main bearing engine. This engine received a substantial increase in power with the introduction of Bosch electronic fuel injection for 1970, making the DS one of the first mass-market cars to use electronic fuel injection.

Lastly, 1973 saw the introduction of the 2347 cc engine of the DS 23 in both carbureted and fuel injected forms. The DS 23 with electronic fuel injection was the most powerful production model, producing 141 horsepower.

IDs and their variants went through a similar evolution, generally lagging the DS by about one year. ID models never received the DS 23 engine or fuel injection. The DS was offered with a number of transmission options, including the "Hydraulique" 4-speed semi-automatic, 4-speed and 5-speed manuals and a 3-speed Borg-Warner full-automatic. The full-automatic transmissions were intended for the US market, but as Citroën withdrew from the US in 1972, the year of highest US sales, due to constrictive road rules, most automatic DSs, being the DS 23 EFI sedans with air conditioning, were sold in Australia.

Lamborghini 350 GT, 1964

Lamborghini 350 GT, 1964

 

The Lamborghini 350GT was the first production car by Lamborghini, first shown at the Turin Motor Show in 1963.

The car featured a 3.5 litre quad-cam V-12 engine (hence its designation), independent rear suspension (while Ferrari still used live rear axles) and a controversial 2+1 semi-fastback body by Carrozzeria Touring of Milan.
The 350GT generally drew high praises at the time for its flexible and high-revving engine, its stable cornering, even on rough surfaces, and its high level of finish. 120 copies were built from 1963 to 1966.

Honda S600, 1964

Honda S600, 1964

Honda S600, 1964

Lamborghini 350 GT, 1964

Lamborghini 350 GT, 1964

 

The Lamborghini 350GT was the first production car by Lamborghini, first shown at the Turin Motor Show in 1963.

The car featured a 3.5 litre quad-cam V-12 engine (hence its designation), independent rear suspension (while Ferrari still used live rear axles) and a controversial 2+1 semi-fastback body by Carrozzeria Touring of Milan.

The 350GT generally drew high praises at the time for its flexible and high-revving engine, its stable cornering, even on rough surfaces, and its high level of finish. 120 copies were built from 1963 to 1966.

Honda S600, 1964

Honda S600, 1964

Honda S600, 1964

Pontiac GTO, 1964

Pontiac GTO, 1964

The Pontiac GTO was an automobile built by Pontiac from 1964 to 1974, and by General Motors Holden in Australia from 2003 to 2006. It is often considered the first true muscle car. From 1964 until 1973.5, it was closely related to the Pontiac Tempest, but for its final year it was based on the Pontiac Ventura. The 21st century GTO is essentially a left hand drive Holden Monaro, itself a coupe variant of the Holden Commodore.

Origins

The GTO was the brainchild of Pontiac engineer Russell Gee, an engine specialist, and Pontiac chief engineer John De Lorean. Shane Wiser was the first to think of the idea of the GTO. In early 1963, General Motors management issued an edict banning divisions from involvement in auto racing. At the time, Pontiac's advertising and marketing approach was heavily based on performance, and racing was an important component of that strategy. Jim Wangers proposed a way to retain the performance image that the division had cultivated with a new focus on street performance. It involved transforming the upcoming redesigned Tempest (which was set to revert to a conventional front-engine, front transmission, rear-wheel drive configuration) into a "Super Tempest" with the larger 389 in³ (6.5 L) Pontiac V8 engine from the full-sized Pontiac Catalina and Bonneville in place of the standard 326 in³ (5.3 L) Tempest V8. By promoting the big-engine Tempest as a special high-performance model, they could appeal to the speed-minded youth market (which had also been recognized by Ford Motor Company's Lee Iacocca, who was at that time preparing the Ford Mustang).

The name, which was DeLorean's idea, was inspired by the Ferrari 250 GTO, the highly successful race car. It is an acronym for Gran Turismo Omologato, Italian for homologated for racing in the GT class. The name drew protest from purists, who considered it close to sacrilege.

The GTO was technically a violation of GM policy limiting the A-body intermediate line to a maximum engine displacement of 330 in³ (5.4 L). Since the GTO was an option package and not standard equipment, it could be considered to fall into a loophole in the policy. Pontiac General Manager Elliot "Pete" Estes approved the new model, although sales manager Frank Bridge, who did not believe it would find a market, insisted on limiting initial production to no more than 5,000 cars. Had the model been a failure, Estes likely would have been reprimanded. As it turned out, it was a great success.

First generation

1964

The first Pontiac GTO was an option package for the Pontiac LeMans, available with the two-door sedan, hardtop coupe, and convertible body styles. For US$ 296, it included the 389 in³ V8 (rated at 325 hp (242 kW) at 4800 rpm) with a single Carter AFB four-barrel carburetor and dual exhaust, chromed valve covers and air cleaner, 7 blade clutch fan, a floor-shifted three-speed manual transmission with Hurst shifter, stiffer springs, larger diameter front sway bar, wider wheels with 7.50 x 14 redline tires, hood scoops, and GTO badges. Optional equipment included a four-speed manual transmission, two-speed automatic transmission, a more powerful "Tri-Power" carburation rated at 348 hp (260 kW), metallic drum brake linings, limited slip differential, heavy-duty cooling, ride and handling package, and the usual array of power and convenience accessories. With every available option, the GTO cost about US$ 4,500 and weighed around 3,500 pounds (1,600 kg).

Most contemporary road tests used the more powerful Tri-Power engine and four-speed. Car Life clocked a GTO so equipped at 0-60 miles per hour (0-97 km/h) in 6.6 seconds, through the standing quarter mile in 14.8 seconds with a top speed of 99 miles per hour (158 km/h). Like most testers, they criticized the slow steering, particularly without power steering, and inadequate drum brakes, which were identical to those of the normal Tempest. Car and Driver incited controversy when it printed that a GTO that had supposedly been tuned with the "Bobcat" kit offered by Royal Pontiac of Royal Oak, Michigan, was clocked at a quarter mile time of 12.8 seconds and a top speed of 112 mph (179 km/h) on racing slicks. Later reports strongly suggest that the Car and Driver GTOs were equipped with a 421 in³ (6.9 L) engine that was optional in full-sized Pontiacs. Since the two engines were difficult to distinguish externally, the subterfuge was not immediately obvious. Frank Bridge's sales forecast proved inaccurate: the GTO package had sold 10,000 units before the beginning of the 1964 calendar year, and total sales were 32,450.

Bobcat

Throughout the 1960s, Royal Pontiac, a Pontiac car dealer in Royal Oak, Michigan, offered a special tune-up package for Pontiac 389 engines. Many were fitted to GTOs, and the components and instructions could be purchased by mail as well as installed by the dealer. The name "Bobcat" came from the improvised badges created for the modified cars, combining letters from the "Bonneville" and "Catalina" nameplates. Many of the Pontiacs made available for magazine testing were equipped with the Bobcat kit. The GTO Bobcat accelerated 0-60 in 4.6 seconds (this 0-60 time is now equalled by the factory 2005-06 GTO with automatic transmission and no modification).

The precise components of the kit varied but generally included pieces to modify the spark advance of the distributor, limiting spark advance to 34-36° at no more than 3,000 rpm (advancing the timing at high rpm for increased power), a thinner head gasket to raise compression to about 11.23:1, a gasket to block the heat riser of the carburetor (keeping it cooler), larger carburetor jets, high-capacity oil pump, and fiberglass shims with lock nuts to hold the hydraulic valve lifters at their maximum point of adjustment, allowing the engine to rev higher without "floating" the valves. Properly installed, the kit could add between 30 and 50 horsepower (20-40 kW), although it required high-octane superpremium gasoline of over 100 octane to avoid spark knock with the higher compression and advanced timing.

1965

The Tempest line, including the GTO, was restyled for the 1965 model year, adding 3.1 inches (7.9 cm) to the overall length while retaining the same wheelbase and interior dimensions. It sported Pontiac's characteristic vertically stacked quad headlights. Overall weight increased about 100 pounds (45 kg). Brake lining area increased nearly 15%. The dashboard design was improved, and an optional rally gauge cluster added a more legible tachometer and oil pressure gauge.

The 389 engine had revised cylinder heads with re-cored intake passages, improving breathing. Rated power increased to 335 hp (250 kW) @ 5,000 rpm for the base 4—barrel engine; the Tri-Power was rated 360 hp ((268 kW) @ 5,200 rpm. The Tri-Power engine had slightly less torque than the base engine, 424 ft·lbf (574 N·m) @ 3,600 rpm versus 431 ft·lbf (584 N·m) @ 3,200 rpm. Transmission and axle ratio choices remained the same.

The restyled GTO had a new simulated hood scoop. A rare, dealer-installed option was a metal underhood pan and gaskets that allowed the scoop to be opened, transforming a cosmetic device into a functional cold air intake. The scoop was low enough that its effectiveness was questionable (it was unlikely to pick up anything but boundary layer air), but it at least admitted cooler, denser air, and allowed more of the engine's formidable roar to escape.

Car Life tested a 1965 GTO with Tri-Power and what they considered the most desirable options (close-ratio four-speed manual transmission, power steering, metallic brakes, rally wheels, 4.11 limited-slip differential, and Rally Gauge Cluster), with a total sticker price of US$3,643.79. With two testers and equipment aboard, they recorded 0-60 miles per hour (0-97 km/h) in 5.8 seconds, the standing quarter mile in 14.5 seconds with a trap speed of 100 miles per hour (160 km/h), and an observed top speed of 114 miles per hour (182.4 km/h) at the engine's 6,000 rpm redline. Even Motor Trend's four-barrel test car, a heavier convertible handicapped by the two-speed automatic transmission and the lack of a limited slip differential, ran 0-60 mph in 7 seconds and through the quarter mile in 16.1 seconds at 89 miles per hour (142.4 km/h).

Major criticisms of the GTO continued to center on its slow steering (ratio of 17.5:1, four turns lock-to-lock) and mediocre brakes. Car Life was satisfied with the metallic brakes on its GTO, but Motor Trend and Road Test found the standard drums with organic linings to be alarmingly inadequate in high-speed driving.

Sales of the GTO, abetted by a formidable marketing and promotional campaign that included songs and various merchandise, more than doubled to 75,342. It was already spawning many imitators, both within other GM divisions and its competitors.

1966

Pontiac's intermediate line was restyled again for 1966,

gaining more curvaceous styling with kicked-up rear fender lines for a "Coke-bottle" look, and a slightly "tunneled" backlight. Overall length grew only fractionally, to 206.4 inches (524 cm), still on a 115 inch (292 cm) wheelbase, while width expanded to 74.4 inches (189 cm). Rear track increased one inch (2.5 cm). Overall weight remained about the same. The GTO became a separate model series, rather than an option package, with unique grille and tail lights, available as a pillared sports coupe, a hardtop sans pillars, or a convertible. Also an automotive industry first, plastic front grilles replaced the pot metal and aluminum versions seen on earlier years. New Strato bucket seats were introduced with higher and thinner seat backs and contoured cushions for added comfort and adjustable headrests were introduced as a new option. The instrument panel was redesigned and more integrated than in previous years with the ignition switch moved from the far left of the dash to the right of the steering wheel. Four pod instruments continued, and the GTO's dash was highlighted by walnut veneer trim. The 1966 model year is viewed by many as the most iconic of all GTOs because of its independent model status and because it was the last year Pontiac offered the 389 Tri Power engine configuration.

Engine choices remained the same as the previous year. A new rare engine option was offered: the XS engine option consisted of a factory Ram Air set up with a new 744 high lift cam. Approximately 35 factory installed Ram Air packages are believed to have been built, though 300 dealership installed Ram Air packages are estimated to have been ordered. On paper, the package was said to produce the same 360 hp as the non-Ram Air, Tri Power car, though these figures are believed to have been grossly underestimated in order to get past GM mandates.

1967

Styling remained essentially unchanged for 1967, but the GTO saw several significant mechanical changes.

A corporate policy decision banned multiple carburetors for all cars except the Chevrolet Corvette, so the Tri-Power engine was cancelled and replaced with new quadrajet four-barrel carburetor. Chevrolet was able to keep the tri-power set up to help with their image; the GTO was really becoming a serious competition problem for them. To compensate, the 389 engine received a slightly wider cylinder bore (4.12 inches, 104.7 mm) for a total displacement of 400 in³ (6.6 L). Torque increased slightly, from 431 to 441 ft-lbf (584 to 598 N·m) for the base engine, from 424 to 438 ft-lbf (575 to 594 N·m) for the optional engine but power remained the same. Testers found little performance difference, although the distinctive sound and fury of the Tri-Power was missed.

Two new engines were offered. The first was an economy engine, also 400 in³ but with a two-barrel carburetor, 8.6:1 compression, and a rating of 265 hp (198 kW) and 397 ft-lbf (538 N·m) of torque. Offered only with an automatic, it was not well received by GTO buyers. The second engine offered at an extra cost of US$263.30 over the standard high-output engine, was the Ram Air engine. The package, which included a functional hood scoop (much like the previous dealer-installed set-up), featured stiffer valve springs and a longer-duration camshaft. Rated power and torque were unchanged, although the engine was certainly stronger than that of the standard 360 hp (268 kW) GTO. It was available only with 3.90:1 or 4.33:1 differential gearing, and its "hotter" camshaft left it with a notably lumpier idle and less cooperative part-throttle response.

Emission controls, including an air injector system, were fitted in GTOs sold in California only.

The two-speed automatic was replaced with the three-speed Turbo-Hydramatic TH400, which was available with any engine. When the Strato bucket seats and console were ordered, the TH was further enhanced by the use of Hurst's Dual-Gate shifter, which permitted automatic shifting in "Drive' or manual selection through the gears. It was generally considered an equal match for the four-speed in most performance aspects. Meanwhile, the Tempest's inadequate drum brakes could be replaced by optional disc brakes on the front wheels (for US$104.79, including power boost), a vast improvement in both braking performance and fade resistance.

Hot Rod Magazine tested a 1967 Ram Air GTO with Turbo-Hydramatic and 3.90 gearing, and obtained a quarter-mile performance of 14.51 seconds @ 98.79 miles per hour (158.99 km/h) in pure-stock form, rising to 14.11 @ 101.23 miles per hour (162.91 km/h) with accessory drive belts removed, new spark plugs, and a slight modification to the carburetor. Car Life's similar car ran 0-60 mph (0-97 km/h) in 6.1 seconds and the quarter in 14.5 seconds @ 102 mph (163 km/h) with 4.33 rear differential. They were critical, however, of the Ram Air's behavior and tendency to overheat in traffic, as well as the ease with which a careless driver could exceed the 5,600 rpm redline in top gear (which limited the car to a maximum speed of 107 mph (171 km/h) with a 4.33 axle ratio).

Citroen DS 19 Cabrio, 1964

Citroen DS 19 Cabrio, 1964

The Citroën DS (also known as Déesse, or Goddess, after the punning initials in French) was an automobile produced by the French manufacturer Citroën between 1955 and 1975. Citroën sold nearly 1.5 million D-series during its 20 years of production.The DS is well-known for its futuristic, aerodynamic body design, and for its innovative technology (including its hydropneumatic self-leveling suspension system).

The DS advanced the achievable standards in terms of ride quality, roadholding, handling, and braking in an automobile. Automotive journalists of the time often noted that competitors took decades to adapt to the higher standards it set. The smooth, aerodynamic body lines gave the car a futuristic appearance. While it looked very unusual in 1955, public tastes appear to have caught up with the DS in the post-Ford Taurus/Audi 100 era.

Model history
After 18 years of development in secret as the successor to the venerable Traction Avant, the DS 19 was introduced on October 5, 1955 at the Paris Motor Show. The car's appearance and innovative engineering captured the imagination of the public and the automobile industry almost overnight. 743 orders were taken in the first 15 minutes of the show, and orders for the first day totalled 12,000.

Far from being just a fascinating technology in search of a purpose, contemporary journalists were effusive in noting how the DS dramatically pushed the envelope in the ride vs. handling compromise possible in a motor vehicle.

The high price tag, however, hurt general sales in a country still recovering from World War II 10 years earlier, and a submodel, the ID (another pun: in French, Idée, or Idea), was introduced in 1957 to appeal to more cost-conscious buyers. The ID shared the same body with the DS, but had more traditional features under the hood. It had no power steering (though this was added as an option later), and instead of the hydraulically controlled manual transmission and clutch, it had a conventional clutch and transmission. Interestingly, the first model series was called 11D, a clear reminder of the last model of the Traction Avant, the 11C. A station wagon variant, the ID Break, was introduced in 1958.

Outside of France, the car's radical and cosmopolitan design appealed to non-conformists. A United States advertisement summarised this selling point: "It takes a special person to drive a special car".

Throughout its model lifetime, the DS managed to remain ahead of its time. It featured power disc brakes, a hydropneumatic suspension including an automatic levelling system and variable ground clearance, power steering and a semi-automatic transmission. A fiberglass roof reduced weight transfer. Inboard front brakes (as well as an independent suspension) reduced unsprung weight. Different front and rear track widths and tire sizes reduced the understeer typical of front-engined and front-wheel drive cars.

Despite the rather leisurely acceleration afforded by its small four-cylinder engine, the DS was successful in motorsports like rallying, where sustained speeds on poor surfaces are paramount.

The DS came in third in the 1999 Car of the Century competition, recognizing the the world's most influential auto designs. Winner and second place went to the Ford Model T and the Mini. It placed fifth on Automobile Magazine "100 Coolest Cars" listing in 2005.
History will remember the DS for many reasons, including the fact it was the first production car with front disc brakes.

Technical innovations

Hydraulic system
The hydraulic system of the DS 19 was a revolution. Previously hydraulics had been restricted to use in brakes and power steering; the DS used them for the suspension, clutch and transmission. The later ID19 had manual steering and a simplified power braking system.

Suspension
At a time when few passenger vehicles had caught up with the four-wheel independent suspension of the Traction Avant, the application of the hydraulic system to the car's suspension system to provide true self-levelling was a stunning move. This application - 'hydropneumatic suspension' - was pioneered the year before on the rear of the top of range Traction Avant 15CV-H.
At first it was often described as air/oil suspension, since both elements played a key role.

Each wheel was connected not to a spring, but to a hydraulic suspension unit consisting of:
* a sphere of about 12 cm in diameter containing pressurised nitrogen
* a cylinder containing hydraulic fluid screwed to the suspension sphere
* a piston inside the cylinder connected by levers to the suspension itself
* a damper valve between the piston and the sphere

A membrane in the sphere prevented the nitrogen from escaping. The motion of the wheels translated to a motion of the piston, which acted on the oil in the nitrogen cushion and provided the spring effect. The damper valve took place of the shock absorber in conventional suspensions.

The hydraulic cylinder was fed with hydraulic fluid from the main pressure reservoir via a height corrector, a valve controlled by the mid-position of the anti-roll bar connected to the axle. If the suspension was too low, the height corrector introduced high-pressure fluid. If it was too high, it released fluid back to the fluid reservoir. In this manner, it maintained a constant height. A control in the cabin allowed the driver to select one of five heights:
* normal riding height.
* two slightly higher riding heights, for poor terrain.
* two extreme positions for changing wheels.

The DS did not have a jack for lifting the car off the ground. Instead, the hydraulic system enabled wheel changes with the aid of a simple adjustable stand.

Source and reserve of pressure
The central part of the hydraulic system was the high pressure reservoir, which maintained a pressure of between 130 and 150 bar in two accumulators. These accumulators were very similar in construction to the suspension spheres. One was dedicated to the brakes, and the other ran the other hydraulic systems. Thus in case of a hydraulic failure (a surprisingly infrequent occurrence), the first indication would be that the steering became heavy, followed by the gearbox not working; only later would the brakes fail.

Hydraulic fluid
The original hydropneumatic system used a vegetable oil (LHV or liquide hydraulique végétale) similar to that used in other cars at the time. Very soon, Citroën changed to using a synthetic fluid (LHS or liquide hydraulique synthétique). Both of these had the disadvantage that they are hygroscopic, as is the case with most brake fluids. Disuse allows water to enter the hydraulic components causing deterioration and expensive maintenance work. The difficulty with hygroscopic hydraulic fluid was exacerbated in the DS/ID due to the extreme rise and fall in the fluid level in the reservoir, which went from nearly full to nearly empty when the suspension "got up" and the 6 accumulators in the system filled with fluid. With every "inhalation" of fresh moisture- (and dust-) laden air, the fluid absorbed more water. In August 1967, Citroën introduced a new mineral oil-based fluid LHM, or liquide hydraulique minérale. This fluid was much less aggressive on the system and it remains in use to the present day.

Briefly illegal in the United States (US federal law requires motor vehicle brake fluid to be red - an exception had to be granted to Citroën), LHM has since been adopted by manufacturers like Rolls-Royce, Jaguar, BMW, and Audi under different labels, like "Total," "Pentosin," and others.

LHM required completely different materials for the seals. Using either fluid in the incorrect system would completely destroy the hydraulic seals very quickly. To help avoid this problem, Citroën added a bright green dye to the LHM fluid and also painted all hydraulic elements bright green. The former LHS parts were painted black.

Several different hydraulic pumps were used. The DS used a seven-cylinder axial piston pump driven off two belts and delivering 175 bar of pressure. The ID19, with its simpler hydraulic system, had a single cylinder pump.

Gearbox and clutch
The mechanical aspects of the gearbox and clutch were completely conventional and the same elements were used in the ID 19.

The gear change control consisted of:
* Hydraulic gear selector.
* Clutch control. This was the most complicated part. The speed of engagement of the clutch was controlled by:
* A centrifugal regulator, sensing engine rpm and driven off the camshaft by a belt
* The position of the butterfly valve in the carburettor (i.e. the position of the accelerator)
* The brake circuit: when the brake was pressed, the engine idle speed dropped to a rpm below the clutch engagement speed, thus preventing friction while stopped in gear at traffic lights. When the brake was released, the idle speed increased to the clutch dragging speed. The car would then "creep" much like automatic transmission cars. This drop in idle throttle position also caused the car to have more engine drag when the brakes were applied even before the car slowed to the idle speed in gear, preventing the engine from "pulling" against the brakes.

Impact on Citroën brand development
The 1955 DS in one stroke cemented the Citroën brand name as an automotive innovator. In fact, the DS caused such a huge sensation that Citroën was fearful future models would not be bold enough. Other than variations on the very basic 2 cylinder economy car Citroën 2CV, like the Citroën Ami, no new models were introduced from 1955 to 1970.

The DS was a large, expensive executive car and a downward brand extension was attempted, but without result. Throughout the late 1950s and 1960s Citroën developed many new vehicles for the very large market segments between the 2CV and the DS, occupied by vehicles like the Peugeot 403, Renault 16 and Ford Cortina. None made it to production. Either they had uneconomic build costs, or were ordinary "me too" cars, not up to the company's high standard of innovation. Because Citroën was owned by Michelin as a sort of research laboratory, such experimentation was possible. Citroën finally did introduce the clever Citroën GS in 1970, which sold a spectacular 2.5 million units.

DS in the US
While the DS was a hit in Europe, it seemed rather odd in the United States. Ostensibly a luxurious car, it did not have the basic features that buyers of that era expected to find on such a vehicle - fully automatic transmission, air conditioning, power windows and a reasonably powerful engine. The DS price point was similar to the contemporary Cadillac luxury car. Also, people at the time wanted only the newest models, which changed every year, like fashion, yet the DS appeared vaguely derivative of the 1950 Hudson Hornet step-down design.

Outdated US legislation also banned one of the car's more advanced features, aerodynamic headlamps, now common in US automobiles. Ultimately, 38,000 units were sold. The first year of the aerodynamic glass over the DS' headlights along with driving lights turned by the steering, was also the first year these features were outlawed in the US.

Design variations
The DS always maintained its size and shape, with easily removable, unstressed body panels, but certain design changes did occur.

A station wagon version was introduced in 1958. It was known by various names in different markets (Break in France, Safari and Familiale in the UK, Wagon in the US, and Citroën Australia used the terms Safari and Station-Wagon). It had a steel roof to support the standard roof rack.

In September 1962, the DS was restyled with a more aerodynamically efficient nose, better ventilation and other improvements. It retained the open two headlamp appearance, but was available with an optional set of driving lights mounted on the front fenders. In 1965 a luxury upgrade kit, the DS Pallas (after Greek goddess Pallas), was introduced. This included comfort features such as better noise insulation, leather upholstery and external trim embellishments.

In 1967, the DS and ID was again restyled. This version had a more streamlined headlamp design, giving the car a notably shark-like appearance. This design had four headlights under a smooth glass canopy, and the inner set swivelled with the steering wheel. This allowed the driver to see 'around' turns, especially valuable on twisting roads driven at high speed at night.

The feature was not allowed in the US at the time (see World Forum for Harmonization of Vehicle Regulations), so a version with four exposed headlights that did not swivel was made for the US market.

The station wagon edition, the Break (called the ID Safari on the UK market) and "Familiale", was also upgraded. The hydraulic fluid changed in all markets (except the US) to the technically superior LHM (Liquide Hydraulique Minérale).

Rarest and most collectible of all DS variants, a convertible was offered from 1958 until 1973. The convertibles were built in small series by French carrossier Henri Chapron, for the Citroën factory. In addition, Chapron also produced a few coupés, non-works convertibles and special sedans (DS Lorraine for instance).

DS engines
As with all French cars, the DS design was impacted by the tax horsepower system, which effectively mandated very small engines.

Unlike the Traction Avant predecessor, there was no top-of-range model with a powerful six cylinder engine. The DS was designed around an air cooled flat six based on the design of the 2 cylinder engine of the 2CV, similar to the motor in the Porsche 911. Technical issues forced this idea to be scrapped.

Thus, for such a modern car, the engine of the original DS 19 was also old-fashioned. It was derived from the engine of the 11CV Traction Avant (models 11B and 11C). It was an OHV four-cylinder engine with three main bearings and dry liners, and a bore of 78 mm and a stroke of 100 mm, giving a volumetric displacement of 1911 cc. The cylinder head had been reworked; the 11C had a reverse-flow cast iron cylinder head and generated 60 hp at 3800 rpm; by contrast, the DS 19 had an aluminium cross-flow head with hemispherical combustion chambers and generated 75 hp at 4500 rpm. Apart from these details, there was very little difference between the engines: even the locations of the cylinder head studs were the same, so that it was possible to put the cylinder head of a DS on a Traction Avant engine and run it.

Like the Traction Avant, the DS had the gearbox mounted in front of the engine, with the differential in between. Thus the DS is a really a mid engine front wheel drive car. It initially had a four-speed transmission and clutch, operated by a hydraulic controller. To change gears, the driver flicked a lever behind the steering wheel to the next position and eased-up on the accelerator pedal. The hydraulic controller disengaged the clutch, engaged the nominated gear, and re-engaged the clutch. Manual transmission control was a lower-cost option. The later and simpler ID19 also had the same gearbox and clutch, manually operated. In the 1970s a five-speed manual and 3-speed fully-automatic were introduced, in addition to the original four-speed unit.

The DS and ID powerplants evolved throughout its 20 year production life. The car was underpowered and faced constant mechanical changes to boost the performance of the four-cylinder engine. The initial 1911 cc 3 main bearing engine (carried forward from the Traction Avant) of the DS 19 was replaced in 1965 with the 1985 cc 5 bearing motor of the DS 19a (called DS20 from September 1969).

The DS 21 was also introduced for model year 1965. This was a 2175 cc, 5 main bearing engine. This engine received a substantial increase in power with the introduction of Bosch electronic fuel injection for 1970, making the DS one of the first mass-market cars to use electronic fuel injection.

Lastly, 1973 saw the introduction of the 2347 cc engine of the DS 23 in both carbureted and fuel injected forms. The DS 23 with electronic fuel injection was the most powerful production model, producing 141 horsepower.

IDs and their variants went through a similar evolution, generally lagging the DS by about one year. ID models never received the DS 23 engine or fuel injection. The DS was offered with a number of transmission options, including the "Hydraulique" 4-speed semi-automatic, 4-speed and 5-speed manuals and a 3-speed Borg-Warner full-automatic. The full-automatic transmissions were intended for the US market, but as Citroën withdrew from the US in 1972, the year of highest US sales, due to constrictive road rules, most automatic DSs, being the DS 23 EFI sedans with air conditioning, were sold in Australia.

Pontiac GTO

Pontiac GTO 1964

The Pontiac GTO was an automobile built by Pontiac from 1964 to 1974, and by General Motors Holden in Australia from 2003 to 2006. It is often considered the first true muscle car. From 1964 until 1973.5, it was closely related to the Pontiac Tempest, but for its final year it was based on the Pontiac Ventura. The 21st century GTO is essentially a left hand drive Holden Monaro, itself a coupe variant of the Holden Commodore.

Origins
The GTO was the brainchild of Pontiac engineer Russell Gee, an engine specialist, and Pontiac chief engineer John De Lorean. Shane Wiser was the first to think of the idea of the GTO. In early 1963, General Motors management issued an edict banning divisions from involvement in auto racing. At the time, Pontiac's advertising and marketing approach was heavily based on performance, and racing was an important component of that strategy. Jim Wangers proposed a way to retain the performance image that the division had cultivated with a new focus on street performance. It involved transforming the upcoming redesigned Tempest (which was set to revert to a conventional front-engine, front transmission, rear-wheel drive configuration) into a "Super Tempest" with the larger 389 in³ (6.5 L) Pontiac V8 engine from the full-sized Pontiac Catalina and Bonneville in place of the standard 326 in³ (5.3 L) Tempest V8. By promoting the big-engine Tempest as a special high-performance model, they could appeal to the speed-minded youth market (which had also been recognized by Ford Motor Company's Lee Iacocca, who was at that time preparing the Ford Mustang).

The name, which was DeLorean's idea, was inspired by the Ferrari 250 GTO, the highly successful race car. It is an acronym for Gran Turismo Omologato, Italian for homologated for racing in the GT class. The name drew protest from purists, who considered it close to sacrilege.

The GTO was technically a violation of GM policy limiting the A-body intermediate line to a maximum engine displacement of 330 in³ (5.4 L). Since the GTO was an option package and not standard equipment, it could be considered to fall into a loophole in the policy. Pontiac General Manager Elliot "Pete" Estes approved the new model, although sales manager Frank Bridge, who did not believe it would find a market, insisted on limiting initial production to no more than 5,000 cars. Had the model been a failure, Estes likely would have been reprimanded. As it turned out, it was a great success.

First generation
1964
The first Pontiac GTO was an option package for the Pontiac LeMans, available with the two-door sedan, hardtop coupe, and convertible body styles. For US$ 296, it included the 389 in³ V8 (rated at 325 hp (242 kW) at 4800 rpm) with a single Carter AFB four-barrel carburetor and dual exhaust, chromed valve covers and air cleaner, 7 blade clutch fan, a floor-shifted three-speed manual transmission with Hurst shifter, stiffer springs, larger diameter front sway bar, wider wheels with 7.50 x 14 redline tires, hood scoops, and GTO badges. Optional equipment included a four-speed manual transmission, two-speed automatic transmission, a more powerful "Tri-Power" carburation rated at 348 hp (260 kW), metallic drum brake linings, limited slip differential, heavy-duty cooling, ride and handling package, and the usual array of power and convenience accessories. With every available option, the GTO cost about US$ 4,500 and weighed around 3,500 pounds (1,600 kg).

Most contemporary road tests used the more powerful Tri-Power engine and four-speed. Car Life clocked a GTO so equipped at 0-60 miles per hour (0-97 km/h) in 6.6 seconds, through the standing quarter mile in 14.8 seconds with a top speed of 99 miles per hour (158 km/h). Like most testers, they criticized the slow steering, particularly without power steering, and inadequate drum brakes, which were identical to those of the normal Tempest. Car and Driver incited controversy when it printed that a GTO that had supposedly been tuned with the "Bobcat" kit offered by Royal Pontiac of Royal Oak, Michigan, was clocked at a quarter mile time of 12.8 seconds and a top speed of 112 mph (179 km/h) on racing slicks. Later reports strongly suggest that the Car and Driver GTOs were equipped with a 421 in³ (6.9 L) engine that was optional in full-sized Pontiacs. Since the two engines were difficult to distinguish externally, the subterfuge was not immediately obvious. Frank Bridge's sales forecast proved inaccurate: the GTO package had sold 10,000 units before the beginning of the 1964 calendar year, and total sales were 32,450.

Bobcat
Throughout the 1960s, Royal Pontiac, a Pontiac car dealer in Royal Oak, Michigan, offered a special tune-up package for Pontiac 389 engines. Many were fitted to GTOs, and the components and instructions could be purchased by mail as well as installed by the dealer. The name "Bobcat" came from the improvised badges created for the modified cars, combining letters from the "Bonneville" and "Catalina" nameplates. Many of the Pontiacs made available for magazine testing were equipped with the Bobcat kit. The GTO Bobcat accelerated 0-60 in 4.6 seconds (this 0-60 time is now equalled by the factory 2005-06 GTO with automatic transmission and no modification).

The precise components of the kit varied but generally included pieces to modify the spark advance of the distributor, limiting spark advance to 34-36° at no more than 3,000 rpm (advancing the timing at high rpm for increased power), a thinner head gasket to raise compression to about 11.23:1, a gasket to block the heat riser of the carburetor (keeping it cooler), larger carburetor jets, high-capacity oil pump, and fiberglass shims with lock nuts to hold the hydraulic valve lifters at their maximum point of adjustment, allowing the engine to rev higher without "floating" the valves. Properly installed, the kit could add between 30 and 50 horsepower (20-40 kW), although it required high-octane superpremium gasoline of over 100 octane to avoid spark knock with the higher compression and advanced timing.

1965
The Tempest line, including the GTO, was restyled for the 1965 model year, adding 3.1 inches (7.9 cm) to the overall length while retaining the same wheelbase and interior dimensions. It sported Pontiac's characteristic vertically stacked quad headlights. Overall weight increased about 100 pounds (45 kg). Brake lining area increased nearly 15%. The dashboard design was improved, and an optional rally gauge cluster added a more legible tachometer and oil pressure gauge.

The 389 engine had revised cylinder heads with re-cored intake passages, improving breathing. Rated power increased to 335 hp (250 kW) @ 5,000 rpm for the base 4—barrel engine; the Tri-Power was rated 360 hp ((268 kW) @ 5,200 rpm. The Tri-Power engine had slightly less torque than the base engine, 424 ft·lbf (574 N·m) @ 3,600 rpm versus 431 ft·lbf (584 N·m) @ 3,200 rpm. Transmission and axle ratio choices remained the same.

The restyled GTO had a new simulated hood scoop. A rare, dealer-installed option was a metal underhood pan and gaskets that allowed the scoop to be opened, transforming a cosmetic device into a functional cold air intake. The scoop was low enough that its effectiveness was questionable (it was unlikely to pick up anything but boundary layer air), but it at least admitted cooler, denser air, and allowed more of the engine's formidable roar to escape.

Car Life tested a 1965 GTO with Tri-Power and what they considered the most desirable options (close-ratio four-speed manual transmission, power steering, metallic brakes, rally wheels, 4.11 limited-slip differential, and Rally Gauge Cluster), with a total sticker price of US$3,643.79. With two testers and equipment aboard, they recorded 0-60 miles per hour (0-97 km/h) in 5.8 seconds, the standing quarter mile in 14.5 seconds with a trap speed of 100 miles per hour (160 km/h), and an observed top speed of 114 miles per hour (182.4 km/h) at the engine's 6,000 rpm redline. Even Motor Trend's four-barrel test car, a heavier convertible handicapped by the two-speed automatic transmission and the lack of a limited slip differential, ran 0-60 mph in 7 seconds and through the quarter mile in 16.1 seconds at 89 miles per hour (142.4 km/h).

Major criticisms of the GTO continued to center on its slow steering (ratio of 17.5:1, four turns lock-to-lock) and mediocre brakes. Car Life was satisfied with the metallic brakes on its GTO, but Motor Trend and Road Test found the standard drums with organic linings to be alarmingly inadequate in high-speed driving.

Sales of the GTO, abetted by a formidable marketing and promotional campaign that included songs and various merchandise, more than doubled to 75,342. It was already spawning many imitators, both within other GM divisions and its competitors.

1966
Pontiac's intermediate line was restyled again for 1966, gaining more curvaceous styling with kicked-up rear fender lines for a "Coke-bottle" look, and a slightly "tunneled" backlight. Overall length grew only fractionally, to 206.4 inches (524 cm), still on a 115 inch (292 cm) wheelbase, while width expanded to 74.4 inches (189 cm). Rear track increased one inch (2.5 cm). Overall weight remained about the same. The GTO became a separate model series, rather than an option package, with unique grille and tail lights, available as a pillared sports coupe, a hardtop sans pillars, or a convertible. Also an automotive industry first, plastic front grilles replaced the pot metal and aluminum versions seen on earlier years. New Strato bucket seats were introduced with higher and thinner seat backs and contoured cushions for added comfort and adjustable headrests were introduced as a new option. The instrument panel was redesigned and more integrated than in previous years with the ignition switch moved from the far left of the dash to the right of the steering wheel. Four pod instruments continued, and the GTO's dash was highlighted by walnut veneer trim. The 1966 model year is viewed by many as the most iconic of all GTOs because of its independent model status and because it was the last year Pontiac offered the 389 Tri Power engine configuration.

Engine choices remained the same as the previous year. A new rare engine option was offered: the XS engine option consisted of a factory Ram Air set up with a new 744 high lift cam. Approximately 35 factory installed Ram Air packages are believed to have been built, though 300 dealership installed Ram Air packages are estimated to have been ordered. On paper, the package was said to produce the same 360 hp as the non-Ram Air, Tri Power car, though these figures are believed to have been grossly underestimated in order to get past GM mandates.

Sales increased to 96,946, the highest production figure for all GTO years. Although Pontiac had strenuously promoted the GTO in advertising as the "GTO Tiger," it had become known in the youth market as the "Goat." Pontiac management attempted to make use of the new nickname in advertising but were vetoed by upper management, which was dismayed by its irreverent tone.

1967
Styling remained essentially unchanged for 1967, but the GTO saw several significant mechanical changes.

A corporate policy decision banned multiple carburetors for all cars except the Chevrolet Corvette, so the Tri-Power engine was cancelled and replaced with new quadrajet four-barrel carburetor. Chevrolet was able to keep the tri-power set up to help with their image; the GTO was really becoming a serious competition problem for them. To compensate, the 389 engine received a slightly wider cylinder bore (4.12 inches, 104.7 mm) for a total displacement of 400 in³ (6.6 L). Torque increased slightly, from 431 to 441 ft-lbf (584 to 598 N·m) for the base engine, from 424 to 438 ft-lbf (575 to 594 N·m) for the optional engine but power remained the same. Testers found little performance difference, although the distinctive sound and fury of the Tri-Power was missed.

Two new engines were offered. The first was an economy engine, also 400 in³ but with a two-barrel carburetor, 8.6:1 compression, and a rating of 265 hp (198 kW) and 397 ft-lbf (538 N·m) of torque. Offered only with an automatic, it was not well received by GTO buyers. The second engine offered at an extra cost of US$263.30 over the standard high-output engine, was the Ram Air engine. The package, which included a functional hood scoop (much like the previous dealer-installed set-up), featured stiffer valve springs and a longer-duration camshaft. Rated power and torque were unchanged, although the engine was certainly stronger than that of the standard 360 hp (268 kW) GTO. It was available only with 3.90:1 or 4.33:1 differential gearing, and its "hotter" camshaft left it with a notably lumpier idle and less cooperative part-throttle response.

Emission controls, including an air injector system, were fitted in GTOs sold in California only.

The two-speed automatic was replaced with the three-speed Turbo-Hydramatic TH400, which was available with any engine. When the Strato bucket seats and console were ordered, the TH was further enhanced by the use of Hurst's Dual-Gate shifter, which permitted automatic shifting in "Drive' or manual selection through the gears. It was generally considered an equal match for the four-speed in most performance aspects. Meanwhile, the Tempest's inadequate drum brakes could be replaced by optional disc brakes on the front wheels (for US$104.79, including power boost), a vast improvement in both braking performance and fade resistance.

Hot Rod Magazine tested a 1967 Ram Air GTO with Turbo-Hydramatic and 3.90 gearing, and obtained a quarter-mile performance of 14.51 seconds @ 98.79 miles per hour (158.99 km/h) in pure-stock form, rising to 14.11 @ 101.23 miles per hour (162.91 km/h) with accessory drive belts removed, new spark plugs, and a slight modification to the carburetor. Car Life's similar car ran 0-60 mph (0-97 km/h) in 6.1 seconds and the quarter in 14.5 seconds @ 102 mph (163 km/h) with 4.33 rear differential. They were critical, however, of the Ram Air's behavior and tendency to overheat in traffic, as well as the ease with which a careless driver could exceed the 5,600 rpm redline in top gear (which limited the car to a maximum speed of 107 mph (171 km/h) with a 4.33 axle ratio). Nor was it cheap: for performance and appointments very similar to their 1965 Tri-Power, the price was US$4,422, a 20% increase.

The GTO sales remained high at 81,722.