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|Disco Inferno: The Infamous Pontiac Trans Am Turbo|
|Written by Aaron Severson|
|Sunday, 23 March 2008 13:55|
Edmunds.com called this car's engine a pathetic travesty. Its muscular styling still conjures up bad memories of gold chains and exposed chest hair, a last gasp of disco-era glory. It was Pontiac's first turbocharged production car, but it also brought down the curtain on a storied era of unique Pontiac engines. This is the story of the little-loved, oft-forgotten Pontiac Firebird Trans Am Turbo.
Even before the advent of emissions standards, the cost of designing a completely new engine was daunting. Design, development, testing, tooling, setting up supply chains -- it's a complicated process, and the price tag for the whole enterprise rises quickly. It's no surprise that most manufacturers share engines across as many models as possible, even across different brands, to spread those costs around.
We may take it as a sign of General Motors' once vast wealth and market share, then, that until the late 1970s GM's individual divisions designed and manufactured most of their own engines. There were a few instances of one division using another's engines, usually for low-volume applications -- Pontiac bought a few Buick aluminum V8s for the 1961-1962 Tempest; Oldsmobile used Buick's Fireball V6 for some F-85s and Eighty-Eights -- but those were the exception, and divisional leaders preferred to avoid such sharing. The result was that the corporation had a plethora of different engines of similar capacities and outputs. By 1969, for instance, Buick, Chevy, Olds, and Pontiac all offered 350 cu. in. (5.7 L) engines, each of distinctly different design. Since each division's output topped that of some rivals' entire corporations, it seemed an acceptable indulgence.
While Chevrolet, Oldsmobile, and Buick each had distinct small-block and big-block V8 engine lines, Pontiac really had only one. Pontiac's "Strato-Streak" V8 had bowed for 1955, replacing the division's hoary flathead engines, which dated back to the 1930s. It had certain features in common with the contemporary small-block Chevy, such as rocker arms pivoting on studded ball joints, rather than rocker shafts (a feature that had actually been developed by Pontiac engineers and shared with Chevrolet), but it had some significant internal differences. It was also somewhat bigger and heavier than the Chevy engine, with greater growth potential.
Grow, the Strato-Streak did -- from 287 cubic inches (4.7 L) in '55 to 455 (7.5 L) in 1970. Over the years, it was offered in a bewildering number of states of tune. Fuel injected, it had powered the first Bonneville, Bunkie Knudsen's declaration of intent that Pontiac was no longer grandma's car. In highly tuned 421 (6.9 L) Super Duty form, it had been a formidable competitor on both drag strip and NASCAR oval. In 389 (6.4 L) form, it had made the reputation of the class-defining GTO, progenitor of the sixties muscle car.
The Pontiac V8 was a sturdy engine with considerable power potential, but it was on the porky side, particularly in its small-displacement versions. The 350 was a good 70 pounds (32 kg) heavier than a Chevy 350 and more than 100 pounds (46 kg) heavier than the Ford 302 (4.9 L), which had adverse effects on weight distribution and fuel economy, particularly for smaller cars.
303 AND 301
Smaller cars and smaller engines figured high on GM's list of priorities in the mid-seventies. The Clean Air Act of 1970 had mandated a set of federal emissions standards that were slated to become progressively more stringent over the course of the decade. California had instituted the first pollution control rules back in 1963, followed by the initial federal standards of 1968, but those rules had regulated smog-producing emissions (unburned hydrocarbons, carbon monoxide, and nitrogen oxide) as a percentage of the exhaust volume, in parts per million. The new rules were based on total emissions released (measured, curiously, in grams per mile), which tended to favor smaller displacement engines. In addition, the OPEC oil embargo of late 1973 led in 1975 to the passage of the first Corporate Average Fuel Economy (CAFE) standards, which took effect for the 1978 model year. CAFE required an automaker's entire fleet to exceed a minimum average gas mileage (initially 18 mpg, 13.1 L/100 km) in a standardized testing regimen; failure to meet the CAFE target would result in substantial fines. Under CAFE rules, Detroit could still sell big cars with big engines, but they were obliged to also sell more fuel-efficient vehicles, which meant smaller engines.
At Pontiac, engineers began a crash program to develop some less thirsty powerplants. Pontiac had had an innovative overhead-cam six in the late sixties, but it was canceled after 1969, leaving a bulky, 250 cu. in. (4.1 L), Chevrolet-designed straight six and Pontiac's aging V8 in 350 cu. in. (5.7 L), 400 cu. in. (6.6L ), and 455 cu. in. (7.5 L) versions. The six made only 100 net horsepower (75 kW), which was hardly adequate for Pontiac's increasingly heavy cars, while the 350 was too big and thirsty to remain the division's bread-and-butter engine. As a stopgap, Pontiac adopted Oldsmobile's new 260 cu. in. (4.2L) V8 as its base V8 starting in 1975, and the year after that, Buick's reborn 231 cu. in. (3.8L) V6 replaced the 250 six. However, Pontiac leadership still very much wanted a small V8 of their own. A completely new, clean-sheet engine would have been ideal, but with the division simultaneously struggling with new federal safety rules, resources were stretched thin. Pontiac's engineering staff took a hard look at the existing 350 to see what could be done with it.
Back in the late sixties, Pontiac had done a great deal of work on a downsized version of the 350 for racing use, the elusive Ram Air V 303 engine. Intended to meet SCCA requirements for Trans Am, which mandated a displacement limit of 305 cubic inches (5.0 L), the 303 was a painstaking revamp of the 350, with a short deck, very short stroke, and many internal changes to improve breathing and reduce reciprocating mass. It produced impressive performance, at least at high speeds, but development delays and concerns about regulatory compliance meant that it was produced only in tiny numbers, none for street use. Still, the 303 project gave engineers some grounding in what could be done with the aging V8.
The new version was just as thoroughly re-engineered as the 303, but with a very different set of design priorities. The new version had thinner cylinder walls and internal webs, siamesed intake ports (with each port serving multiple cylinders), and fewer crankshaft counterweights. It was anything but a high-performance engine -- the changes compromised breathing and ultimate durability -- but they whittled an impressive 120 pounds off the engine's mass. Unlike the 303, which combined the 400's 4.12-inch (104.6 mm) bore with a 2.87-inch (72.9-mm) stroke, for better rev potential, the new engine had a 4.0-inch (101.6 mm) bore and a 3.0-inch (76.2 mm) stroke, for better low-end torque. Its actual displacement was 302 cubic inches (4.9 L), but to keep buyers from thinking Pontiac was buying Ford engines, it was labeled the 301. In 1977, it replaced the Olds 260 as the standard V8 for most Pontiac models, as well as some Buicks. (A 265 cu. in. (4.3L) version, with a smaller bore, was added a year later.) In its initial form, with a two-throat carburetor, the 301 made a modest 135 net horsepower (101 kW) and returned reasonable fuel economy, if not great acceleration.
Which brings us to the Firebird. The Pontiac Firebird, introduced in 1967, had been revamped midway through the 1970 model year. Mechanically, it was much the same as before, but it had a sleek new body that many contemporary reviewers thought would befit a Ferrari or Maserati. Top of the line was the Firebird Trans Am, a model introduced on a very limited basis in 1969, carrying a standard 400 cu. in. (6.6 L) engine and a conspicuous array of scoops, extractor vents, and spoilers.
Despite the racy looks, the new Firebird arrived just as pony car sales were crashing, and GM came very close to canceling it after 1972. It earned a last-minute reprieve, and by mid-decade sales had recovered nicely, thanks in no small part to the Trans Am's starring role in the 1977 Burt Reynolds action-comedy Smokey and the Bandit. Firebird sales reached a peak of 187,285 for 1978, about half of which were Trans Ams.
The Firebird's 1970 1/2 body would survive through 1981 with only modest stylistic changes, including a set of well-integrated 5-mph (8-kph) bumpers (mandated by federal law) that made it one of the few cars of its era not to look like it was wearing battering rams. More noticeable was the dramatic Firebird hood decal (introduced in 1973), which was quickly dubbed -- not necessarily affectionately -- the "screaming chicken."
Under the hood, the screaming had become a good deal more muted. The Firebird had been one of the last bastions of genuine muscle car power -- the 1973-74 Super Duty 455 was no less formidable than the meanest of its pre-smog rivals -- but by 1976, the combination of emissions requirements, prohibitive insurance rates, and reduced compression had pulled the Firebird's talons. The 455 cu. in. (7.5 L) engine was available through 1976, but was now down to only 200 net horsepower (149 kW), pathetic for such an enormous engine. When it was gone, the top option was the 400, with the same power, but less torque. In California, where the 400 failed to pass that state's stricter emissions laws, Pontiac was compelled to substitute an Oldsmobile 403 cu. in. (6.6 L) V8 with 185 hp (138 kW). Since a well-equipped Trans Am weighed more than 3,600 pounds (1,635 kg), performance was less than startling with either engine. Even so, the Firebird's sales remained robust, suggesting that buyers were more interested in image than real speed.
Over at Buick, there had recently been a revival of an item GM had pioneered for passenger car use and then abandoned a decade earlier: the turbocharger. Buick's pace car for the 1976 Indianapolis 500 sported a turbocharged version of the Buick V6, and a production version followed for 1978. The turbo V6 made up to 165 hp (123 kW), as much as many GM V8s of that era, but it returned much better fuel economy, at least in the EPA tests that determined CAFE. With even stricter emissions and fuel economy standards set to arrive in the eighties, turbocharging took on a new appeal.
At the General Motors Institute in Flint (now the Kettering University) in 1977, instructor Jim Lyons, also a performance engineer at Pontiac, assigned his students to develop a turbocharged V8. The students came up with a turbocharged version of the Pontiac 301 that could meet 1980 federal emissions standards. It originally was only a student exercise, but Lyons was impressed enough by the results that he brought it to his boss, chief engine engineer Leo Hilke, and arranged for it to be refined into a production program. Development engines were run in 1979 Trans Ams, and it entered production for the 1980 model year.
No 'hot' version of the 301 had ever been serious contemplated -- indeed, the changes made to reduce its weight were not very conducive to high performance. The 301T involved quite a few internal changes, adding back some of the internal 'beef' that had been removed relative to the older 350, making the turbocharged engine's block and heads somewhat stronger than those of its normally aspirated counterpart. The 301T had a very mild camshaft (milder than the normally aspirated 301), 7.5:1 compression, a higher-capacity oil pump, a modified Quadrajet four-barrel carburetor, and a Garrett TBO-305 turbocharger, with a wastegate permitting a maximum of about 9.0 psi (0.6 bar) boost. A novelty was an electronic control unit that was supposed to retard engine timing in order to limit detonation under boost. The 301T was rated at 210 horsepower (157 kW) and 345 lb-ft (467 N-m) of torque, a healthy increase over the 150 hp (112 kW) and 235 lb-ft (318 N-m) of the 4-bbl 301, and somewhat stronger than either the 400 or 403. The turbo package cost a reasonable $350, and was offered only with automatic transmission. It met federal emissions standards, but wasn't available in California.
TURBO TRANS AM
The words "Firebird Trans Am Turbo" would seem to connote furious performance, but the Turbo T/A was not as impressive as one might expect. The major problem was that the electronic spark control was not entirely successful in eliminating detonation. Motor Trend's November 1979 test of an early Turbo Trans Am went from 0 to 60 mph (0 to 97 kph) in a reasonably brisk 8.0 seconds, with the quarter mile (402 meters) coming up in the mid-16s, but a subsequent test in June 1980 was a full second slower. All testers reported detonation at full throttle, at least with pump fuel. Road & Track's April 1980 test car was no faster than a normally aspirated Trans Am 301, taking 17.5 seconds to run the quarter mile. Still, few cars of the era offered better performance, at least without spending a lot more money. A contemporary Corvette or Datsun 280ZX Turbo was somewhat faster than the Trans Am Turbo, but cost nearly twice as much.
The ultimate Trans Am Turbo was the 1980 Indianapolis 500 Pace Car replica. Our photo car is one of 5,700 of these replicas, which were essentially Trans Ams with the turbo engine and every available Firebird option, including a T-top roof, air conditioning, limited-slip differential, white-painted alloy wheels, a full load of convenience features, and the WS6 Performance Handling Package, which included four-wheel disc brakes and stiffer suspension components. Pace Car replicas were available only in Cameo White with gray accents -- and a unique hood decal even more dramatic than the normal Firebird. The Pace Car carried a daunting $11,194 sticker price, compared to the $7,529 base price of a normal Trans Am with the turbo engine. (The Pace Car replica wasn't available in California, again because the turbo engine failed to meet California emissions standards; our photo car must have originally been registered in another state.)
The Pace Car was the gaudiest example of a car whose styling was becoming seriously dated. While Firebirds with the WS6 package were among the best-handling, best-stopping cars sold in America at the time, the 10-year-old design was clearly long in the tooth, and sales for 1980 dropped precipitously. The turbo was back for 1981, now rated at 200 horsepower (149 kW), but it was the end of the line.
THE LAST OF THE INDEPENDENTS
A crisp, futuristic new Firebird bowed the following year, a body style that shortly would be immortalized as KITT of the TV series Knight Rider, but the turbo engine did not return, nor did the 301. GM management finally made the difficult decision to standardize engines across most of the company (save for Cadillac), and subsequent Firebird V8s would be small-block Chevys. The last survivor of the era of unique Pontiac engines was the 151 cu. in. (2.5L) "Iron Duke" inline-four, which had been designed at the same time as the 301 and shared some of its tooling and dimensions.
From an economic or logical standpoint it's difficult to argue with GM's adoption of "corporate" engines, but it was yet another blow to the identity of the individual divisions. By then, there was little choose between Chevrolet, Pontiac, Oldsmobile, and Buick other than styling and standard equipment. The loss of distinction was openly mocked in the advertising of some rival automakers, and, combined with a litany of embarrassing quality problems and recalls, did lasting damage to GM's formerly unassailable market position.
The 301 and the Turbo T/A have gotten a bad rap over the years. Many hot rodders consider it a hopeless case; while more power can be extracted, common hop-up techniques often do more harm than good. Well-kept turbos have lived 150,000 miles (240,000 km) or more, but the 301T never matched the durability of its V8 predecessors. For enthusiasts the Turbo T/A is at best a curiosity, never enjoying the cult status of the later Buick Grand National and GNX turbo cars. Nonetheless, the 301 has its partisans, thanks to its status as the "Last of the Mohicans," the final true Pontiac V8.
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NOTES ON SOURCES
Much of the information for this article came from Joe Richter's excellent website on the Pontiac 301 (2007, http://301garage. com/, accessed 20 March 2008), and Lee Rehorn's 301 Turbo Shrine (n.d., 301Garage.com, http://301garage. com/ Rehorn/301shrine.html, accessed 20 March 2008) Additional information on the Turbo Trans Ams, including performance figures, came from the Before Black website ("b4black," n.d., BeforeBlack, http://www.beforeblack. net/ transam.htm, accessed 20 March 2008) and Hitman's Pontiac Trans Am ("Hitman," date unknown, The Trans Am Information Site, http://www.78ta. com/ index.php, accessed 20 March 2008). We also consulted Edmunds' Firebird history (Edmunds' Firebird History (n.d., Edmunds.com, http://www.edmunds. com/ pontiac/firebird/history.html, accessed 20 March 2008) and the Auto Editors of Consumer Guide, Encyclopedia of American Cars: Over 65 Years of Automotive History (Lincolnwood, IL: Publications International, 1996).
Information on the earlier Ram Air V 303 came primarily from Stan Rarden and Paul Zazarine, "The Engine That Never Was," Pontiac Enthusiast, March-April 2004, pp. 44-45, and Eric Dahlquist, "The Great Breakaway Conspiracy," Motor Trend, June 1969 (Vol. 21, No. 6), pp. 72-74.
This article's title was suggested by the 1976 single by the Trammps, which was written by Leroy Green and Ron Kersey.