The Buick Grand National and GNX Cut a Deep, Dark Path Through GM Muscle Car History
These hot Buicks defined American muscle in the 1980s.
Benjamin HuntingWriterMecum AuctionsPhotographer
Alan MuirIllustratorAug 28, 2024
The
Buick GNX (short for “Grand National Experimental”) was the ultimate expression of G-body performance; a rear-wheel-drive coupe that served as a coda for the Detroit automaker’s history of producing fast and fun-to-drive coupes. Arriving in 1987, the GNX took the Buick Regal—which was already offered in go-fast
Grand National form—and turned up the wick on turbo technology that Buick had been perfecting for nearly a decade. The result was one of the quickest and most visually distinctive cars of the 1980s, and this low-production model has remained an icon of American muscle to collectors and fans nearly 40 years after it first debuted.
Buick’s ’70s Experiments Feed Its Turbo ’80s Efforts
By the beginning of the '80s,
Buick had carved out a niche for itself compared to other General Motors divisions by pursuing turbocharged V-6 engines instead of the
more common V-8 options found in models from Chevrolet, Oldsmobile, and Pontiac. Its initial efforts dated back to 1978, when the company began offering a four-barrel, 165-hp turbo 3.8-liter engine in several of its models (with a slightly less-mighty two-barrel carburetor option also available).
This engine was itself derived from a series of turbocharged concept cars put together earlier that decade by engineer Don Baker, Buick’s chief of experimental development Jack DeCou, and Buick’s head engineer Lloyd Reuss. The company’s turbo powerplant made its public debut under the hood of the Buick Century Pace Car at the 1976 Indy 500, where it served as proof-of-concept for an electronic engine management system that included a knock sensor—a key piece of turbo technology.
The Grand National Lays the Groundwork for the GNX
At the start of 1982 Buick took advantage of its recent championship win in NASCAR—which was often referred to as “Grand National” racing—to create a commemorative model called the Grand National. Based on the Buick Regal coupe, it was little more than a paintjob and sticker-package, but it laid the foundation for the brand to push forward with the most potent version of its turbocharged formula to date.
By the time the Buick Grand National name once again found its way onto the Regal’s order sheet, it was 1984, and a lot had changed. Sequential fuel injection, computer-controlled ignition, and a relocated turbocharger for the 3.8-liter V-6 amounted to a serious punch with the pedal down: 200 horsepower and 300 lb-ft of torque.
By 1986 the presence of an intercooler added 30 extra horses, up another 10 the following year, but deep inside Buick a secret skunkworks was taking the Grand National concept as far as it possibly could. This “Grand National Experimental” model, or GNX, arrived in 1987 and sent shockwaves across not just the rest of the industry, but also through the halls of General Motors itself.
The Buick GNX Takes Turbo Engineering to New Heights
Though it looked very similar to the Buick Grand National, the GNX was a quantum leap forward for the brand in terms of engineering acumen. The vehicle was built in partnership with ASC/McLaren, which meant that the GNX didn’t share line space with the Regal but was actually assembled at a separate facility, further adding to its air of exclusivity.
The drivetrain was radically revised to include better breathing heads, a more robust Garrett
turbocharger that made use of a lighter, quicker-spinning ceramic impeller and reduced-drag turbine shaft seals, a gaping exhaust system, and, of course, an improved intercooler (also sourced from Garrett). Operating at 15 psi, the setup was good for 276 horsepower and 360 lb-ft of torque—at least that was the advertised number. Some independent tests of the era quoted the GNX’s output at over 300 horsepower.
The GNX also received suspension upgrades over the Grand National (a longitudinal rear ladder bar, more aggressive springs, and an aluminum rear axle housing cover), better heat management (thanks to front fender vents, a transmission cooler for its four-speed automatic, and a front-mounted oil cooler), and 16-inch tires. The GNX’s body was stiffened compared to the standard Regal/Grand National.