The only proper turbocharged muscle car, the Grand National used turbocharging to eat V8s for breakfast.
Behold the majesty that is the Buick Grand National. Forget about technology, the Grand National had it, but it was much more important as a means to change the public's opinion on turbocharging. This was Detroit's only real turbo muscle car, but thanks to its turbocharger, this was the V6 muscle car which had no problem outrunning V8-equipped cars. For the first time, the muscle car set began to realize there was a potential replacement for displacement.
The Grand National didn't start off the monster it would become, and it took almost 10 years before Buick's turbo technology would be up to the task of turning out a good performance car. With the introduction of the second-generation Regal in 1978, Buick decided to bring out a turbocharged engine for the Regal Sport Coupe. This was a V6 from the Sixties fitted with a Garrett turbo and a choice of either a two- or four-barrel carburetor. The two-barrel made 150 horsepower and the four-barrel 165. That, sadly, isn't much less than contemporary V8 engines made (185 horsepower in the Corvette that year, for example), but the turbo engines also didn't really work very well.
The carburetors used were really suited to turbo duty, and the Sport Coupe never really achieved much fame. The first Grand National debuted in 1982, but this wasn't quite the car we think of today. This usually had a big 4.1-liter V6 which was naturally aspirated, although a small number had the carbureted turbo mills. There was no Grand National for 1983, but Buick brought it back for '84 and it was much improved. The engine now had a sequential fuel injection system to go with the turbo, and the 3.8-liter V8 made 200 horsepower and 300lb-ft of torque. A distributor-less ignition system was also used, and the car was technologically way ahead of the rest of GM.
The Grand National received it's blacked-out color scheme for the first time in 1984 as well, a menacing feature which would become a trademark. Though just 2,000 units were produced in '84, the world would begin to get an idea of what they could do. Yes, a V8 Camaro could run the quarter-mile in 17.0 seconds and the Corvette could run it in 15.1 seconds. The Grand National clocked a 15.9. An intercooler was added in 1986, and horsepower went up 235 and then 245 in 1987, along with 355lb-ft of torque. The '87 could get to 60mph in under 5 seconds, and was the most popular year of the GN. Also debuting in '87 was the GNX.
This was "the Grand National to end all Grand Nationals". For the GNX, the engine was given a going-over and was now "smarter". For the GNX, it produced 276 horsepower and 360lb-ft of torque. It went from 0 to 60 in 4.7 seconds and was an awesome testament to the effectiveness of turbocharging. GM required that all Grand Nationals be sold with automatic transmissions, so that the car wouldn't be a threat to the Corvette, although the big torque numbers from the turbo engine would have been a lot for most manuals of the day to deal with.
The Grand National was running the quarter-mile in the 14-second range by the time it was retired, and owners soon found that just a few easy modifications could bring it down to 13s. The GN was a monster in a straight line, with the lag which plagued turbo engines in the Eighties being less of a problem on a drag strip than on a road course. The GN could pull .79g on a skidpad, which is something of a miracle for a GM product from the Eighties, although the turbo lag and automatic transmission didn't do it any favors in the twists. A new Regal debuted in 1988, and the Grand National went out with the old body.
Thus would begin Buick's slide into irrelevance which nearly killed it off. The Grand National is still a car much sought after by collectors. The '87 models are considered the most definitive, but these are also the most numerous, with Buick having built 27,590 units that year. The Grand National did a lot to change perceptions of turbocharging in America in the Eighties. Turbocharging was mostly something foreign and exotic during this time, and although there were some American cars which effectively made use of the technology, the Grand National was faster and more badass than any of them.
The Grand National was a proper muscle car in an era when V8 muscle cars were pretty unimpressive. A lot of muscle car enthusiasts still preferred a V8 even after the Grand National, but it was still enough to make them sit up and take notice.