Most EFI GM performance fans are familiar with the intercooled Turbo Buicks of 1986 and 1987. These G-bodies were loaded with a 231-inch V-6 engine, enhanced with a Bosch sequential EFI system, and stuffed with 12 pounds of chilled boost thanks to a Garrett turbo and intercooler. The 3.8L mills were laughably underrated at 245 horses and 355 lb-ft of torque; one magazine's drag test of an '86 model produced an astounding 13.9 at 98 miles an hour. In a performance decade that saw very few rides crack into the mid-14s, the Turbo Regal simply dominated the '80s.
But the performance nuts over at Buick weren't done-not by a long shot. To commemorate the final year of production, 547 copies of a highly modified, special-edition version would be produced. They called it the GNX.
ASC McLaren was tapped to perform the mods: a different turbo and intercooler for the engine, computer and trans tweaks, 16-inch rims with big 245/255mm rubber and fender flares, and a complete set of analog instrumentation were added.
However, the biggest departure from a regular Turbo Buick was the Panhard bar/torque arm rear suspension system, created to get the most traction possible out of the 276hp/360 lb-ft (wink, wink) V-6. A custom dual-muffler exhaust system was utilized to clear this suspension.
The GNX's look-with few exterior emblems, big meats, and those sexy fender flares-was evil ... and so was its performance: GM claimed a 13.4 e.t. with a solid 104-mph trap speed. How many other factory rides do you know of running low 13s in 1987? Simply badass.
When the rest of the GNXs rolled off the assembly line and went out to spread the gospel of turbo V-6 performance, GNX No. 001 stayed with GM. No. 001 was used for public relations, and the marketing department provided it to the media for newspaper and magazine articles-and more than a few breathtaking testdrives. As our GM source recalls: "It's always been a pristine vehicle, but I'm sure it's been beaten on. I believe there were multiple sets of tires used within the first thousand miles or so."
It would have been easy enough to adjust the LC2-code, 3.8L Turbo V-6's wastegate to provide the GNX's 15-psi boost pressure. However, the Buick engineers did things right: a high-tech turbocharger with a lightweight ceramic impeller and a contamination trap replaced the regular hairdryer, allowing quicker spoolup. A special intercooler was used to more efficiently cool the boosted air, and a heat-resistant intake pipe to the throttle body kept heat out of the charged atmosphere. | 
A Stewart Warner gauge cluster dominates the GNX's interior-this was the only Turbo Buick to get a good set of analog gauges. Another "X"-only touch includes the dash plaque. | 
This GNX turbo heat shield was a classy upgrade over regular TRs. |