These days, turbocharged cars are quite common. As manufacturers strive to meet increasingly stringent government requirements for new vehicles regarding fuel economy and emissions, they’re replacing large-displacement, normally aspirated engines with smaller, more efficient turbo gasoline and diesel engines.
This is not a new idea, however. Very early in the development of the internal combustion engine, engineers realized that pumping in more air and fuel increased power output. Mechanical supercharging was developed in the 1920s as a solution aimed at road and race cars; an air pump driven off the engine’s crankshaft delivered a compressed intake charge.
On a parallel track, turbo-supercharging—as it was called then—was developed for diesel engines that operated for long periods in a limited rpm range, including those found in ships and trains. This setup used a centrifugal supercharger spun by an exhaust-driven turbine. Further developments, such as improved throttle control, led to the turbodiesel road trucks first appearing in Europe at the start of World War II.
During the runup to the war, military aircraft engineers sought to make up for the power losses experienced by internal combustion engines at higher altitudes. Mechanical supercharging was a common solution, but for some very high-performance applications, engineers adapted turbos to gasoline aircraft engines.
These engineers were drawn by the efficiency found in turbocharging; instead of wasting power to drive the compressor—an issue with mechanical supercharging—they’d use exhaust energy that would have been wasted otherwise. Classic warbirds such as the P-38, B-17 and P-47 used turbocharged engines.
After the war, experience with turbocharger technology led engineers to experiment with automobile applications during the 1950s and ’60s. Home-built hotrods and race cars sporting turbos began appearing at dry-lake speed events and even NHRA drag races. Before long, manufacturers were considering them for various race and production car applications—and soon enough, they did. While turbochargers have become quite common today—Ford predicts that soon a sizable portion of their fleet will be powered by their new EcoBoost engine—that trail was blazed by some pioneering milestone products.
1952: Cummins Shakes Up Indy
In the immediate postwar era, a competitive marketplace for mass-produced turbodiesel trucks led the Cummins company to resume prewar efforts to sponsor and provide technical support for entries in the Indy 500. They believed that the power delivery and fuel mileage of a turbodiesel engine would allow them to run the 500 miles with a single pit stop while still cruising at competitive lap speeds.
For the 1952 race, new rules regarding diesel engine displacement convinced Cummins to build their own car. The result was a technological tour de force in the form of a one-off Kurtis Kraft chassis; it was designed around a lay-down aluminum and magnesium Cummins 6.4-liter turbodiesel race engine. Output was reputed to be around 380 horsepower teamed with prodigious torque.
Driver Fred Agabashian set Gasoline Alley tongues wagging when he qualified the huge but sleek torque monster on pole position for the race. The No. 28 Cummins Diesel Special ran strongly early on, but the engine’s intake—located directly behind the grille—was not adequately filtered, allowing the turbo to ingest track debris. The car left the race before the checker was thrown. It never ran again, as the Cummins team felt that they’d made their point.
1962: GM Brings the Turbo to Main Street
After getting their feet wet with turbocharged trucks, General Motors became the first company to offer a turbocharged production car. Actually, they released two of them for the 1962 model year: the Oldsmobile F-85 Jetfire V8 coupe as well as the Chevrolet Corvair Monza Spyder.
GM was looking to improve the power output and efficiency of two relatively small-displacement engines, their 215-cubic-inch Olds V8 as well as their 145-cubic-inch, flat-six Chevy. The corporate engineers devised a suck-through, single-barrel carbureted system that increased power output by roughly 50 horsepower in both cases, the Olds jumping from 155 to 215 horsepower and the Chevy going from 98 horsepower to 150. The Corvair’s flat six would eventually reach 180 horsepower before the option was discontinued a few years later.
Even at a relatively low boost—about 5 psi—the Oldsmobile’s 10.25:1 compression ratio may have been a little optimistic for the gasoline of the time, and the engines had trouble with pinging under hard acceleration. In order to alleviate the problem, GM engineers hastily developed a Turbo-Rocket fluid methyl alcohol/water injection system that required F-85 Jetfire owners to properly mix the fluid and keep the underhood reservoir filled. Not too surprisingly, the turbocharged Olds only lasted for two model years and a little more than 9000 units.
The turbocharged Corvair did a little better, lasting five years with more than 50,000 units sold. The car’s enemy proved to be another Chevrolet product, as the late ’60s were dominated by the brand’s Mustang-fighter, the Camaro. The Corvair’s turbo engine option was discontinued after the 1966 model year in favor of a larger-displacement, normally aspirated engine that lasted until the model’s termination in 1969.
1966: Turbos Return to Indy
By the mid-1960s, USAC Champ Car racing’s relatively liberal rules had become a fertile crucible for automotive technological development, initiated by the mid-engined chassis revolution led by Cooper, Lotus and Lola early in the decade. Ford Racing even developed a dual-overhead cam version of their venerable small-block V8 for USAC and mid-engined applications, specifically for the Indy 500.
The traditional Offenhauser-powered Gasoline Alley gang retaliated, drawing upon their military and hotrod experience to keep pace with Ford’s big-dollar, high-tech efforts. In 1966, the first turbocharged Offy qualified for the Indy 500; Bobby Grim drove an obsolete Watson roadster chassis to more than 158 mph—not too far off Mario Andretti's pole speed of 165-plus mph. In an interesting twist, the first turbo Offy was the last roadster to race in the 500.
Grim wasn’t a contender for the win, but the Indy establishment took notice of the turbo engine’s 500-plus horsepower, a significant advantage over the normally aspirated and supercharged engines powering the rest of the field. It wasn’t long before turbos were being affixed to Offys and Fords alike; the Indy horsepower wars really spooled up, spurred on by the powerful but fragile STP gas turbine cars.
As the teams and engine builders began to develop turbo-specific fuel and ignition systems, qualifying speeds began climbing dramatically. When Bobby Unser won the 1968 Indy 500 with a turbo-Offy fitted in the back of his Eagle chassis, the end of competitive, normally aspirated engines at Indy was sealed.
The turbine engines were eventually legislated out, but turbocharger, chassis and aerodynamic development continued to push speeds even higher. The turbo Offys could make up to 1200 horsepower at more than 54 psi in qualifying trim, while the Foyt engines—A.J. had bought the Ford DOHC engine tooling when Ford pulled out of factory racing in 1972—made a little less. The 1972 pole speed was 196 mph.
Two drivers and one crewmember were killed at Indianapolis in 1973, bringing changes to the Speedway. Starting in 1974, new rules were intended to slow the field, including mandatory popoff valve boost regulators set for 80 inches of mercury, equating to roughly 39 psi of boost.
Turbocharged Offys and Foyts continued powering Champ Cars into the ’70s, with rules outlawing potential power-increasing technologies—including multiple turbos and intercooling. Lower boost limits were also mandated. These steps reduced engine power levels until the 2.65-liter turbocharged version of the classic Cosworth V8 made its way to Indy in 1976.
While turbos left the series in 2008, they’re back for this year.
1973: Porsche Rewrites the Rule Book
When it comes to sheer turbocharged ferocity, many people consider the 1973 Porsche 917/30 Can-Am racer the pinnacle of turbo sports car development. Reputedly packing more than 1500 horsepower in qualifying trim, the 5.4-liter, twin-turbo flat-12 Penske Panzer utterly dominated the 1973 SCCA Can-Am championship in the capable hands of Mark Donohue. He took six of eight races, leaving the once-dominating Shadows, Lolas and McLarens to follow in the long black tire marks that the Porsche seemed to deposit out of every corner.
Porsche developed the very successful 917 coupe for Le Mans and European World Sports Car Championship series in 1969-’71. When the new car debuted later in the 1971 Can-Am season, it was clearly at a horsepower disadvantage to the 800-plus-horsepower, 8-liter aluminum big-block Chevys that powered the McLarens and other competition.
For 1972, Roger Penske’s team driver Mark Donohue worked with Porsche to develop the 917/10K. It featured twin Eberspächer turbos and Bosch mechanical fuel injection. The result was an 850-horsepower machine that Donohue and George Follmer—he replaced Donohue after his Road Atlanta wreck—drove to six wins in nine starts that year.
Donohue wasn’t content, and the downtime gave him and the team the opportunity to consider further developments for the 1973 season. Their weapon would be the 917/30, and changes included a longer wheelbase, revised aerodynamics and an easier-to-manage fuel-injection system. (The throttle response found in the 1972 car could best be described as an on-off switch.) They also revised the driver-controlled boost adjustment—boost was now up to 32 psi—while increasing engine displacement to 5.4 liters. After Donohue dominated the 1973 Can-Am season, the SCCA employed a rule change for the following year that required a minimum fuel mileage of 3 mpg; the 917/30 simply could not attain it.
Penske’s team had one final plan for the car: a run at the FIA closed course world speed record. Donohue piloted his trusty mount at Talladega Superspeedway in 1975 and managed to capture one last record with it, a lap of 221.160 mph.
1973: BMW Brings Turbos Back to the Street
As the 1960s ended, a decade’s worth of racing-oriented turbo technology development on both sides of the Atlantic was bound to find its way back into production cars. Large-displacement V8s ruled the American highways of the time, so it’s not surprising that the first of the modern turbocharged production cars came from Europe in the form of the 1973-’74 BMW 2002 Turbo. It picks up where the turbocharged Oldsmobile and Corvair left off nearly a decade earlier.
The 2002 Turbo evolved from the company’s dominating Group 5 Touring Car effort. The 2002 Turbo retained much of the race car’s mechanical goodness, including a re-engineered braking system, limited-slip differential, quicker steering and Kugelfischer mechanical fuel injection.
Then there was the main feature, a KKK turbocharger bolted to the single-cam, 2.0-liter inline four. It cranked out 170 horsepower and 240 lb.-ft. of torque once everything was spooled up. And it did indeed need to be spooled up, as the factory had reduced the engine’s static compression ratio to 6.9:1 in order to help the engine last in street use.
Given the state of early-’70s fuel-injection technology, the engine didn’t deliver much punch below 4000 rpm. However, when the engine started to boil, the 2002’s light weight and short wheelbase made it somewhat demanding to drive at the limit. The BMW 2002 Turbo was never formally imported to the U.S., although many of the 1672 examples built did seem to end up here.
1974: Porsche Launches an Icon
Porsche’s development of turbocharged cars didn’t end with their participation in the Can-Am series, as much of that experience and technology was being channeled to their 911 road and racing programs. In 1974, the company rather quietly entered a turbocharged 911 Carrera RSR in European sports car races, hoping to get a jump on the following year’s new Group 5 rules.
That turbo Carrera RSR received a 2.1-liter flat six force fed by the venerable Bosch K-Jetronic system and a single KKK turbo. Despite the small engine, the car made a big visual impact thanks to its huge rear tires and fender flares as well as a monstrous rear wing—features that enthusiasts would forever associate with the 911 Turbo and its derivatives.
Later that year, the street version of the turbocharged 911 made its debut at the Paris Auto Show. The 1975 911 Turbo Carrera—designated in-house as the 930—featured a turbocharged, 3.0-liter, 260-horsepower version of the company’s flat six. The engine sat between big tires, wide fenders and the now-iconic whale tail.
Sporting variants of the previous rear-engined 911s had developed a reputation for being demanding at the limit. However, the 930 took that reputation a step further with prodigious power and acceleration—all after a significant throttle lag. This resulted in a tendency to snap oversteer as the rear tires broke loose, followed by even more oversteer if the driver lifted off the throttle.
Still, the ride was rewarding for those with experience. The robust, track-derived brakes stopped the car well after astonishing (for the late 1970s) blasts through its heavy-duty, four-speed gearbox. The steering and grip levels were also as good as anything Porsche had ever produced up to that time.
The turbocharged 911 is still part of the Porsche lineup, and race-ready variants have been terrorizing the track just as long.
1977: Renault Turbocharges F1
Renault decided to get serious about motorsports in the early 1970s, working closely with the Alpine company to develop the A440, A441 and A442 sports cars for the European prototype sports car World Championship and, naturally, Le Mans. This effort would use Le Mans as a steppingstone to Formula 1.
After analyzing the rules of the day, Renault worked with French tuner Gordini to develop a series of single-turbocharged, twin-cam, 2.0-liter V6 engines that would form the basis for a 1.5-liter Formula 1 engine. The Renault RS01 debuted at Silverstone in 1977, ushering in Formula 1’s turbo age. The car featured a 500-horsepower, iron-block, single-turbo powerplant. In all, it was a simple, rugged, rather basic beast; other teams chortled at “the yellow teapot,” noting its remarkable throttle lag and unreliability.
By 1979, the RS01 had given way to the RS10, featuring a conventional (for the time) ground-effect chassis and a second-generation engine built around an alloy block. The new car also included twin turbos and intercooling; better throttle response was among the benefits. The Renaults had a distinct advantage at the high-altitude races, and when Jean-Pierre Jabouille’s Renault won at Dijon, the other teams in the paddock began to take turbo F1 cars seriously.
The Toleman team followed in 1981, entering a turbocharged version of Brian Hart’s inline four. At the same time, Ferrari introduced the twin-turbo, V6-powered 126CK, which Gilles Villeneuve used to win in Monaco and Spain despite its ample turbo lag and handling issues. The Ferrari eventually won the 1982 and 1983 constructors championship.
By 1983, BMW, Honda, Renault, Alfa Romeo, Hart and TAG/Porsche were also supplying turbocharged Formula 1 engines to the various teams. That’s when the horsepower wars really began. These wars were fueled by increasingly exotic brews referred to as “gasoline.” The substance facilitated turbo boost pressures of 45 psi and 700 horsepower in qualifying trim.
Rules for 1984 limited all F1 cars to 240 liters of fuel, as refueling was still verboten at that point. This put a premium on even more sophisticated engine controls to manage consumption. Other tricks were employed, too, such as using liquid nitrogen to supercool fuel before races; this reduced its volume so more could be crammed into the tanks.
The F1 horsepower wars continued unabated in 1985, particularly for qualifying, which saw some engines reaching 5.5 bar boost (over 82 psi) and an estimated 1500 horsepower. That’s 1000 horsepower per liter powering 1200-pound vehicles.
Another fuel reduction in 1986 to 195 liters per race failed to slow the cars significantly, so the FIA set forth rules to outlaw the turbo engines by 1989; rules for 1987 and 1988 intended to choke the beasts down to uncompetitiveness in favor of normally aspirated, 3.5-liter powerplants. However, McLaren, as well as Honda’s RA 168E twin-turbo V6, had the last blowoff in 1988, as Ayrton Senna and Alain Prost won 15 of 16 races in the Gordon Murray-designed low-line McLaren MP4/4 chassis. The curtain was then brought down on the first F1 turbo era, with new, small-displacement turbo engines currently slated to be introduced in 2014.
1982: Porsche Rules Endurance Racing
Porsche was no stranger to turbocharged racers, so when the Group C Prototype rules were announced for the 1982 endurance race season, the company figuratively rubbed their hands together and dug into their toy box to develop a new prototype sports car, designated 956. However, it turned out that things weren’t so easy.
For starters, flat-six engines mounted midship didn’t leave as much room for ground effects tunnels; a “V” configuration offers more room. Since Porsche didn’t have a suitable turbocharged “V”-shaped engine, their engineers mounted the turbo flat-six engine at an angle inside the 956’s aluminum monocoque.
The 2.8-liter, twin-turbo, water-cooled engine came from the 936 prototype program, receiving some tricks from the later 935s and developments for the aborted 1980 IndyCar program. It was managed—finally—by an electronically controlled Bosch fuel- injection system.
When the new car debuted at Silverstone in May of 1982, it came in second overall to a Group 6 Lancia. The new Porsches went on a tear from there, winning just about everything in sight, including a one-two-three finish at Le Mans.
The 956 was originally conceived to be a customer car similar in spirit to the 935—it even featured a full-synchromesh transmission—but it was unsuitable for America’s IMSA GTP rules since it placed the driver’s feet ahead of the front axle centerline. The IMSA rules also didn’t take kindly to the water-cooled powerplant.
Porsche developed the 962 for American customers, stretching the wheelbase to meet the IMSA rules while also adding an updated version of the air-cooled 935 single-turbo engine. (Spotter’s tip: Look for the larger air scoop for the intercooler behind the cockpit.)
The first 962s had the 650-horsepower, 2.8-liter, single-turbo engines, but many teams—including the Holbert and Dyson efforts—opted for the fire-breathing 800-plus-horsepower, high-boost 3.0- and 3.2-liter units offered by Andial and others.
By 1985, the 962 had also supplanted the 956 as the Porsche Group C entry, meaning it was now winning races and championships everywhere it raced, including Le Mans, Daytona and Sebring. The 962 also claimed four straight IMSA titles starting in 1984.
Sports car racing flourished throughout the ’80s. Factory race programs from Jaguar, Ford, Mercedes-Benz, Nissan, Toyota, Chevrolet and even Mazda arrived in IMSA GTP and FIA Group C with armies of engineers and high-tech, high-dollar bespoke equipment. This new competition forced the Porsche customer teams—and IMSA rulemakers—to get very creative as they attempted to keep up with these 1000-plus-horsepower factory turbo rockets.
However, as the worldwide economy slowed during the early ’90s, those manufacturers left sports car racing. The two endurance series collapsed in the vacuum. Those same creative souls who revamped their 962s to keep up with the big-budget factories now adapted them to new sports car packages. The cars kept taking wins, including the 1994 Le Mans victory in a somehow street-legal Dauer 962. (It was essentially factory chassis 962C-176 homologated as a street car by Dauer before being re-prepared for racing.)
The old 935/962-based Porsche turbo flat-six drivetrain wasn’t done even then, as it powered the open-top, Walkinshaw-built Porsche WSC-95/LMP1-98 to victories at Le Mans in 1996 and ’97. A second-place finish at the 1998 Petit Le Mans capped off the engine’s run.
1984: Italy Joins In
Ferrari began serious work with turbocharging in the late 1970s and early 1980s, as their Formula 1 engine development followed Renault’s lead at the time. However, Ferrari didn’t develop any turbos for their road car programs until 1982, when their competition department wanted to build a car—soon to be known as the 288 GTO—to the Group B rules for a possible FIA road racing series.
These technically liberal Group B rules had been adopted from the FIA’s Rally Championship, although the homologation process required that at least 200 units be sold to the general public. Ford, Porsche, MG/Rover, Audi, Lancia, Renault, Peugeot and others were already involved in the Group B scene, meaning there was a good potential pool of entrants.
The Ferrari engineers conjured a Group B version of their mid-engined 308 model, although they didn’t just bolt turbos onto Thomas Magnum’s car and call it a day. They developed a nearly new street-legal race car based on the 308 chassis. In addition to a reworked suspension, the engine orientation was changed from transverse to longitudinal.
The new car’s designation hinted at its engine, a 2.8-liter, twin-cam V8 supplemented by twin IHI turbochargers and intercoolers. It was fed by a Magneti Marelli fuel-injection system.
When the road car was introduced for 1984, it was rated at an even 400 horsepower and 370 lb.-ft. of torque. It was also hailed as a technical milestone for Ferrari and a real grin-inducing drive, even for seasoned exotic car pilots of the time.
Unfortunately, the Group B road racing series was nearly stillborn—Porsche’s 959 was the only other car homologated for it—and the Group B rally tragedies of the mid-’80s effectively legislated the entire FIA program into oblivion. Ferrari only completed 277 of the planned 288 GTOs before halting production in 1985.
Ferrari also built and tested a few race-ready GTO Evoluziones, each one featuring 650 horsepower and even more exotic bodywork—wings, slats, diveplanes and whatnot. The Evo program might have died on the vine, but it became the foundation for Ferrari’s next twin-turbo terror, the legendary plastic-fantastic F40.
1984: Front-Drive Fun
When Chrysler asked for a government loan in the late 1970s to avoid bankruptcy, they staked their near-term survival on the development of smaller, fuel-efficient, front-drive cars based on common platforms and powertrains. Lee Iacocca, the head of Chrysler at the time, also understood the value of image/halo products and performance. He brought in an old friend—Carroll Shelby—to massage some of Chrysler’s products in the same way he did for the Mustang and other Fords during the 1960s.
In 1982, Shelby brought some of Chrysler’s top engineers to a small shop in Whittier, California, to develop Shelby versions of Chrysler’s new 2.2-liter, single-cam, inline-four engines and matching front-drive chassis. The plan also included some limited production runs of Shelby-branded products based on Chrysler hardware; these would be sold through Dodge dealers with Shelby Automobiles franchises.
In 1984, Chrysler released the fruits of this labor. The Dodge Daytona and Plymouth Laser, two swoopy cars based on Chrysler’s new front-drive chassis, featured 146 horsepower thanks to Bosch electronic injection and a Garrett turbocharger. Chrysler and Shelby followed it up for 1985 by adapting that powertrain to the smaller, lighter Dodge Shelby Charger and Omni GLH Turbo. (Yes, the model designation does stand for “Goes Like Hell.”)
Naturally, these cars were in the same vein as the old Mustang GTs: not exactly the most refined motoring experience, but a hoot to hustle around. Also like the old pony cars, prices were reasonable, with the Omni GLH starting at only $7350.
The GLH Turbo was due to be discontinued after the 1986 model year run, so Shelby made arrangements to get the last 500 or so cars off the Belvedere production line—all of them black with gray interiors. They were shipped back to a hastily arranged assembly plant in Whitter.
The Shelby Performance team adapted the intercooled, multi-port fuel-injected induction system developed for Dodge’s 1987 model year while adding a larger Garrett turbocharger. His team also added rebound-adjustable Koni shocks and struts, a special radiator/intercooler assembly, Shelby Centurion 15x6-inch wheels and 205/50R15 Goodyear Gatorback tires. The result was the Shelby GLHS—“Goes Like Hell Somemore.”
Hot Rod magazine trumpeted “GLHS whips GT-350” on the cover, describing a road course shootout between the first Shelby Dodge and the first Shelby Mustang. The little GLHS was crude, but with 175 horsepower on tap and a meaty torque curve—and even a fair amount of torque steer, despite the equal-length halfshaft arrangement—it was able to get to a drag strip’s finish line in about 14.5 seconds. The Shelby GLHS might have only been around for the 1986 model year, but similar cars followed. A Charger GLHS and some Shadow-based CSX variants were created, including the first production variable-geometry turbocharger application in 1989.
1982: Buick Blows a Muscle Car
When Buick introduced the turbocharged, carbureted Regal T-Type for 1978, it was perceived as a nicely performing personal luxury car, a reasonable alternative to Chevy’s Monte Carlo and Pontiac’s Grand Prix. When those chassis were updated in the early ’80s, Buick got into performance in a big way. They developed NASCAR bodywork and normally aspirated V8 and V6 race engines for Winston Cup and Grand National competition.
The Grand National arrived with gusto for 1984. Thanks to a new sequential fuel-injection system and electronic wastegate control, the turbocharged V6 produced 200 horsepower along with 300 lb.-ft. of torque—all in a comfortable, easy-to-drive package. Like the Model T, it only came in one color: black.
Intercooling and a revised fuel-injection system raised output to 245 horsepower and 355 lb.-ft. of torque for 1986. Suddenly, big, bad Buicks were shredding rear tires while leaving V8 cars in the dust. The Buick’s 13-second quarter-mile times blew people’s minds, as a 15-second run was considered quick back then.
The rear-drive Regal was due to be discontinued after the 1987 year, so engineers developed a suitable send-off: the GNX. The 547 black GNXs produced for Buick by McLaren/ASC featured numbered dash plaques and Stewart Warner gauges, fender flares, functional vents and meaty 16-inch wheels.
Then they added more performance: revised intercooler and intake pipes, a new engine management program, a turbo with a ceramic compressor wheel, a dual-muffler exhaust, and a special rear suspension featuring an offset torque arm and Panhard rod. To save weight, the bumper brackets, rear brake drums and other components were formed in aluminum.
The GNX was the fastest-accelerating GM product at the time, with 5-second-flat zero-to-60 times and a 13.2-second time at the drag strip. The performance prompted Buick engineers to plaster “I Brake for Corvettes” bumper stickers on corporate development mules.
While the turbo Buick GNX left after that 1987 model year, its engine ended up in the 1989 Pontiac Turbo Trans-Am. Of the 1550 produced, several paced that year’s Indy 500. Perhaps this was a fitting end to the first golden era of turbocharged cars. Those Trans-Ams paced some of the fastest closed course racers on the planet—and nearly all of them were turbocharged. Just a few short years later, turbochargers became a common sight in dealerships worldwide, too.
