- That Time Pontiac Turbocharged the Trans Am
An innovative solution to beat the Malaise Era blues.
The big-block muscle car had all but gone extinct by the mid-1970s, a victim of two energy crises that sent fuel prices soaring. Stricter emissions standards and newly-effective CAFE (Corporate Average Fuel Economy) standards meant that Pontiac’s 455-cubic-inch (7.5-liter) Firebird Trans Am was long dead, and 1979 would be the last year for Pontiac’s next-biggest engine, the 400-cubic-inch (6.6-liter) V-8.
And yet despite changing consumer tastes, Firebird sales climbed steadily throughout the late 1970s. With other automakers exiting the pony car space and Ford having remade the Mustang as a Pinto clone, Firebird and Camaro were the last of the muscle cars and people still wanted them. How could Pontiac give buyers the power they wanted without a big V-8?
The answer was the turbocharger, which was in common use for aircraft and big-rig engines but still a novelty in the car business. Then as now, the turbo seemed like a good way to get a small engine to perform like a big one, with acceptable fuel economy and emissions. Pontiac wouldn’t have a big displacement V-8 for 1980, but perhaps a turbo could make a smaller engine act like one.
Pontiac preps the 301 for the Trans Am Turbo
Pontiac engineers developed the turbocharged V-8 in a remarkably short 18 months. They started with the division’s 301-cid (4.9-liter) V-8, which had been introduced as an emission-friendly engine for the 1977 model year. (This was the tail end of the era when individual GM divisions designed their own engines, often duplicating similar-size power plants from other brands.) The engine was to be fitted with a 9-psi Garrett TBO-305 turbocharger, and Pontiac fortified it with a reinforced block, beefed up pistons and head gaskets, and a high-pressure oil pump.
The compression ratio was dropped from 8.1:1 to 7.6:1 and the engine was fitted with a special version of the Rochester Quadrajet four-barrel carburetor, which was modified to ensure proper enrichment of the air-fuel mixture when the turbocharger was producing boost. The turbocharger’s electronic controller was borrowed from Buick, which had already turbocharged its 231-cid (3.8-liter) V-6. Also new and notable was a knock sensor, which sensed the vibration of potentially catastrophic pre-ignition knock and signaled the distributor to retard the ignition timing and the turbo controller to reduce boost.
Pontiac offered the new turbocharged 4.9-liter as an option in the Formula Firebird and Trans Am, coupled exclusively to a three-speed automatic and a relatively tall 3.08:1 final drive ratio. With 210 horsepower and 345 lb-ft of torque, it was a significant step up from the 140 horsepower and 240 lb-ft of the naturally-aspirated 301. It was also a credible follow-on to the old 400-cid engine, which delivered 220 horsepower and 320 lb-ft in 1979. More importantly, it bested the 1980 Chevrolet Camaro Z/28’s 350-cid (5.7-liter) V-8 and its 190 horsepower and 280 lb-ft output—and it handily out-paced the best Ford’s new Fox-body Mustang could muster that year, which was a 131-horsepower turbocharged four-cylinder and a 122-horsepower 4.2-liter V-8.
Differentiating the Firebird and Trans Am Turbos
A massive bulge on the driver’s side of the hood, required to clear the relocated carburetor and turbocharger, distinguished turbocharged Firebirds and Trans Ams from the rest of the flock. The optional hood decal had the Firdbird spitting out a larger plume of flame than those on non-turbo cars. Pontiac didn’t fit a traditional boost gauge as standard; instead, the optional boost indicator consisted of three orange lights on the backside of the hood scoop labeled “NORMAL”, “MEDIUM”, and “HIGH” (next to the label “TURBO CHARGE”).
The Trans Am Turbo paced Indy that year, so naturally there was an Indy Pace Car edition, production of which was limited to 5,700. In the film Smokey and the Bandit II, Bo “The Bandit” Darville (Burt Reynolds) upgraded from the 400-cubic-inch Trans Am he drove in the first movie to a new turbo model.
Testing the Turbocharged Trans Am
As the eighties dawned, turbocharged cars were still few and far between. Automobile was not yet in existence, but our sister publication MotorTrend assembled as many turbo cars as it could for a group test. It was an odd bunch: A Saab 900, a Porsche 924S, and the Trans Am Turbo were up against a Buick Riviera with a turbocharged V-6 (the Buick Grand National was still two years in the future), a Chevrolet Monte Carlo with the Buick engine, and a Mazda 626 with an aftermarket turbo kit. A Buick Regal Turbo was sidelined due to knock-sensor problems. Ford declined to supply a turbocharged Mustang or Capri, and Audi likewise demurred with its 5000S turbo.
The Pontiac Trans Am Turbo’s performance numbers were, by standards of the day, reasonably strong. Its 0-60-mph time of 9.05 seconds was best of the bunch; same for its 17.02-second quarter mile, which just barely edged out the Porsche (17.10) and the Saab (17.23). The engine was supposed to feel like an old-school big V-8 rather than a high-strung turbo engine, and according to MotorTrend, it did: “There is no sensation of boost,” they wrote, “only the rush and sound of a V-8 leaping out at 5,000 rpm.” In an impromptu race against the Porsche 924—which cost more than three times as much—the two cars ran neck-and-neck.
MotorTrend‘s scribes noted the Trans Am’s age: “You’ll find that 4.9-liter engine to be the only thing different under its decade-old skin. The rest of the car is like stepping into yesteryear.” But after they’d driven it, they apparently decided yesteryear was a fine place to be. “For a first-year car, the Turbo Trans Am is surprisingly complete,” they wrote. “The no-nonsense interior is like coming back home, and the brutal WS6 suspension makes you never want to leave again.”
Criticisms of the Pontiac Trans Am Turbo
But the 4.9 turbo Trans Am also came in for criticism from several sources. Performance wasn’t quite in the old 400’s league, with the car about a second and a half slower in the quarter mile, though that wasn’t entirely the turbo engine’s fault—the 400 could be had with a four-speed stick and a 3.23:1 final drive ratio, while the Trans Am Turbo was stuck with an automatic and a 3.08 rear end. Finding high-octane fuel could be a challenge, with some unscrupulous gas stations pumping regular unleaded fuel out of their super unleaded pumps. Low octane fuel kicked the 4.9 Turbo’s knock sensor into action, cutting the power. Even MT noticed what they called an “unnerving” amount of knock, a problem for all three domestic turbo cars in their test, but not the imports. (Current owners say the cars run better on today’s high-octane fuels.)
The Trans Am Turbo: What might have been?
The 4.9 Turbo was back for 1981, with a slight drop in horsepower (to 200) and torque (to 340 lb-ft). But its dominance was short-lived: When Pontiac introduced the all-new (and long overdue) 1982 Firebird in late ’81, the turbo was gone. GM was making a corporation-wide effort to reduce engine proliferation, and by executive fiat, Pontiac was out of the V-8 business—instead supplying the Firebird and Camaro’s pitiful 2.5-liter four-cylinder engine, while the V-8 option came from Chevrolet, a 305-cid (5.0-liter) small-block in either 145-horsepower carbureted or 165-horsepower fuel-injected form.
Pontiac fans have speculated about what might have been had the development of the engine been allowed to continue. They speculate that Pontiac might have developed an electronic fuel injection system, switched from a draw-through to a blow-through turbo setup, and added an intercooler, and we think that’s a plausible prediction; Pontiac was known for its performance engineering. (Also, that’s exactlly what Buick did with its turbocharged 3.8-liter V-6.)
Sadly, Pontiac’s engineers would never be given the freedom to develop their own performance V-8s again. The Firebird breathed its last in 2002 and GM shuttered Pontiac in 2010. We’ll never know what could have been—but we’re pretty sure that it could have been great.
|1980 Pontiac Firebird Trans Am Turbo|
|ENGINE||4.9L OHV 16-valve V-8/210 hp @ 4,000 rpm, 345 lb-ft @ 2,000 rpm|
|LAYOUT||2-door, 4-passenger, front-engine, RWD coupe|
|EPA MILEAGE||14/20 mpg city/highway|
|L x W x H||198.1 x 73.0 x 50.3 in|
|0-60 MPH||9.0 sec|
|TOP SPEED||120 mph (est)|
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