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Big, bad, boosted: The 1987-only Buick GNX

Published in blog.hemmings.com

1987 Buick GNX prototype. Photos by Daniel Strohl.

In the early 1980s, Buick faced an image problem. Long seen as a brand for grandparents more concerned with a cushy ride than with performance or handling, Buick’s demographic was aging, and new buyers simply weren’t visiting Buick showrooms. The answer was to borrow a page from the brand’s storied past, when Gran Sport models were used to attract a younger, performance- and image-conscious buyer into Buick dealerships.

When the first Buick Grand National appeared as a 1982-only model, it was little more than an appearance package, but in 1984 a far more sinister Grand National hit the streets, bedecked in black over black and infused with turbocharged V-6 power. Of all the turbocharged Grand National models built from 1984-1987, the ultimate expression of performance came in the form of the car’s swan song, the limited-production, 1987-only Buick GNX.

From 1984-‘86, Buick produced 9,614 Grand Nationals, and by 1987–the final year of production–demand was so high that Buick built 20,194 examples to satisfy its customers. To give the Grand National a fitting farewell, Dave Sharpe, Buick’s chief engineer, petitioned senior management to allow the creation of a “super Grand National,” and thus the GNX was born.

Buick GNX

From the beginning, it was to be a low-volume car, produced for Buick by ASC/McLaren at a “suggested retail price” of $29,290, at a time when a well-equipped Grand National carried a sticker price of $18,295. Initial plans called for production of just 200 GNX models, but to meet escalating demand that quantity ultimately increased to 547 units.

The design goal for GM’s Advanced Concepts Group (which would ultimately set the specifications for the car) was both simple and ambitious: Build the quickest GM production four-seater, ever. Doing so would require extensive modifications to the engine, transmission and even suspension, but the team appointed to develop the car proved to be up to the challenge.

Under the hood, the GNX started with the same 231-cubic-inch V-6 as other Grand National models, but received a special Garrett T-3 turbocharger equipped with a ceramic impeller; an intercooler with the same dimensions as the stock one but more cooling fins per row; a ceramic-coated turbo shield and inlet pipe; a larger diameter dual exhaust; and a recalibrated engine control unit that permitted 15 PSI of boost. The net result was an output of 276 horsepower and 360 pound-feet of torque, a gain of 31 horsepower and five pound-feet of torque over standard Grand National models.

Even the GNX’s transmission received tuning, allowing it to produce crisper shifts to maximize acceleration, and the net result was a car that could sprint from 0-60 mph in 5.5 seconds and run through the quarter-mile in 13.4 seconds at 100 MPH. By comparison, Road & Track reported that a 1987 Corvette with the four-speed manual ran from 0-60 in 5.9 seconds, getting through the quarter-mile in 14.5 seconds at 97 mph.

Underneath, the GNX received a unique rear suspension that used a Panhard bar/ladder bar setup on the car’s Positraction-equipped live rear axle to maximize grip and minimize wheel hop under hard acceleration. Wheels were similar in appearance to those used on the Pontiac Trans Am, but with a different offset and GNX center caps. Measuring eight inches across in front and rear, the 16-inch wheels were shod with Goodyear Eagle Gatorback VR50 tires, 255/50R16 out back (the same size as the Corvette) and 245/50R16 up front.

Like the Gran Sports of the 1960s, the GNX was designed to be fast in a straight line, conceding road course lap records to more agile cars. Brakes consisted of discs up front (with 10.5-inch rotors) and 9.5-inch drums in the rear, the same sizes used on other Grand National models. Even the beefed-up suspension couldn’t mask the Buick’s 3,545-pound curb weight, leaving it with a lateral acceleration of .80 g.

Buick GNX

To cover the meaty Goodyear Gatorback radials, the GNX wore bold fender flares in front and rear, and front fenders also received functional venting. In the cabin, however, the differences between Grand National and GNX models were far more subtle, limited to GNX badging above the glove compartment and a full set of analog Stewart-Warner gauges (including a boost gauge, helpful for dragstrip launches) to keep close tabs on the underhood happenings.

As Martyn Schorr explains in his book, Buick GNX (included, along with a GNX jacket, as a gift to original buyers), ASC had the difficult task of giving the GNX a “High-Intensity” appearance that needed to be both similar to, and distinctive from, the Buick Grand National on which the car was based. All references to the Buick Regal or the Grand National were removed from the GNX’s exterior, which then received just two forged aluminum GNX badges, one on the grille and a second on the trunk lid. The front fender vents, vaguely reminiscent of Buick’s classic “porthole” vents, were deliberately painted in low-gloss to provide contrast to the gleaming black paint. Even the unique instrumentation was chosen to convey a message of high performance, ensuring that the driver knew this was no ordinary Grand National even before the engine was fired up.

The automotive press could not heap enough praise on the GNX, with Car and Driver calling it “an ax-wielding Barbarian laying waste to everything in its path,” while Cars Illustrated proclaimed it “The fastest showroom trim Musclecar ever.” Like the Buick GS models of old, the GNX also looked good going fast, and demand quickly outstripped supply, leading to dealer price gouging. Convinced that the GNX would be an appreciating classic, buyers eagerly paid whatever price necessary to park one in their garage.

Even ASC, the manufacturer of the Buick GNX, touted its investment value. Image courtesy The Old Car Manual Project.

That’s where the tale of the GNX über-Buick takes a sad turn. Many were purchased as investments, meaning that too few buyers got to appreciate the car as the ultimate expression of Buick performance in the 1980s. Today, low-mileage examples cross the auction block with some regularity, now commanding the kinds of prices that original owners hoped to realize thirty years ago.

In 2014, NADA published a value of $72,100 for a GNX in average condition, with a high range value of $103,500. Five years later, NADA puts the average value at $97,700, versus $136,100 for a high-range example. For an original owner, than might represent a reasonable return on investment (overlooking, perhaps, the cost of three-plus decades of care and feeding), but it pales in comparison to a comparable 32-year investment in Microsoft stock: $29,200 invested in 1987 would be worth about $9.5 million today.

The moral to the story? It’s best to buy cars – particularly new cars – for enjoyment behind the wheel, and not as additions to an investment portfolio.