Chevrolet will introduce its all-new ZR1 Corvette convertible at this week’s Los Angeles Auto Show, three weeks after the coupe broke cover in Dubai. Like its coupe brother, the C7 ZR1 is the fastest, most powerful Corvette convertible ever. With its 755-horsepower supercharged V-8 engine, huge breathing and cooling capability (including five new radiators), and a choice of high or low carbon-fiber rear wings, it tests the limits of front-engine, rear-drive performance.
As the fourth Corvette to share ZR1 designation, let’s go back and take a look at what led up to it.
The original ZR1 was limited-production package for the third-generation Corvette that Zora Arkus-Duntov designed for SCCA B-Production racing. It was a $968.95 option that included a cold-air hood, close-ratio four-speed manual, and performance shocks, springs, and stabilizer bars.
Its crown jewel was the then-new LT1 engine, a hot-rodded version of the small-block known for its solid lifters, a throwback to an earlier era before the advent of hydraulics. Solids were more adjustable, producing more horsepower, as well as a beefier engine sound. But hydraulics were more popular at the time since they were cheaper to make and maintain. They self-compensate for valvetrain clearances (valve lash), giving customers years of quiet, maintenance-free service.
But racers wanted horsepower first, and the first ZR1 offered 370 hp, versus 350 hp for other engines with the standard hydraulic lifters.
As Karl Ludvigsen wrote in Corvette, the Star Spangled Sports Car, “The result was a lively engine in the tradition of Duntov cams and fuel injection that could thrust the LT1 through the quarter mile in 14.2 seconds with a trap speed of 102 mph.”
Only 53 ZR1s were built over three years, which makes them worth more. A ZR1 coupe sold for $220,000 at Barrett-Jackson’s 2014 Scottsdale auction.
The gen-four (C4) Corvette ZR-1 was one of the most anticipated Corvettes ever. Known as the “King of the Hill,” it represented Chevrolet’s return to the top of the performance mountain, a car that could fully compete with the fastest cars in the world when it debuted in 1990. Chief engineer Dave McLellan said at the time, “It’s a Corvette, only more so.”
The ZR-1’s core was the LT5 V-8 engine. It was Corvette’s first-ever overhead cam, 32-valve V-8, and it was developed in partnership with Lotus (one of GM’s many acquisitions in the late 1980s) and Mercury Marine, which cast and assembled the LT5’s aluminum block at its plant in Stillwater, Oklahoma. The LT5 put out 375 hp initially; its horsepower was later cranked up to 405 in 1993. With a top speed of 175 mph, it put Corvette back into the conversation among the supercars of its day.
The ZR-1 featured a special wide body with massive, 11-inch-wide Goodyear rear tires. It also came with a special valet key, which would limit horsepower output to unauthorized drivers. To beat gas-guzzler tax penalties, the six-speed ZF manual transmission featured Computer Aided Gear Selection (CAGS), which automatically guided the shifter from first to fourth at lower speeds. But the inevitable lugging caused drivers to feel like they were missing a shift, even though a little more throttle could overcome it.
Chevrolet invited press from around the world to the ZR-1’s media launch in 1989, held in southwestern France. There, the big Corvettes had a chance to prove their mettle on European roads, and the superlatives flowed. The ZR-1 owned the cover of virtually every car magazine in the world.
Sales were initially brisk as more than 3,000 ZR-1s were sold in 1990, all for premium prices as collectors snatched up the early cars, putting them away as investments and hoping to someday make a killing. But only 6,939 ZR-1s were built over the course of five years, and so far they’ve been an investment bust. For a car that cost at least $58,595 (more than $107,700 in today’s dollars), the highest price at auction remains $48,600, achieved by Mecum for a 1995 ZR-1 in 2015.
The ZR-1 failed sales-wise because people couldn’t see the value of a $27,016 price increase over a base Corvette at $31,979. It didn’t help that in 1992, Chevrolet introduced the LT1 V-8, which put out 300 hp without the price premium. Buyers had shied away from the LT5 because of its perceived complexity and concern about parts availability and expert service for an exotic engine at a Chevrolet dealer.
The last ZR-1 came off its Bowling Green, Kentucky, assembly line on April 28, 1995.
All is not lost for those who still own one, though. “ZR-1s seem to have bottomed (out),” Paul Duchene wrote in an October 2016 Hagerty article. “Most seem to sell between $20,000 and $35,000, but the newest is 20 years old, and prices are on the way up. And well they should be; the 6,939 ZR-1s are the least-appreciated Corvettes and the best value in the entire lineup.”
The third generation of the ZR1 was the answer to the question, “What if?”
And the person asking that question was then-GM Chairman Rick Wagoner. In order to understand the full context, Wagoner had praised the sixth-generation (C6) Corvette engineering team for what they had been able to accomplish with a Z06 Corvette that cost $60K. So what could they do for a car that cost $100K?
Because Wagoner was a Duke graduate, the new project became known as the “Blue Devil Corvette.” And as it turned out, the team could accomplish a lot with the help of a new Eaton supercharger. The end result was a quantum leap in Corvette performance, with 638 hp and a top speed of well over 200 mph, thanks to its LS9 supercharged V-8.
In order to get all this power to hook up, a special Launch Control capability was programmed into the Traction Control/Active Handling system. Zero to 60 happened in a scant 3.3 seconds. And the quarter mile could be reached in 11.0 flat at 130 mph.
To increase its power-to-weight ratio, the team made more aggressive use of lightweight components such a carbon-fiber hood with a clear glass window to the supercharger, a carbon-fiber roof/roof bow, as well as carbon-fiber front fenders and wheel housings. The C6 ZR1 also featured Brembo carbon-ceramic brakes.
The chassis was a modified version of the Z06 aluminum structure, which featured hydroformed aluminum rails connected to a center tunnel backbone. Like the Z06, the engine cradle and roof structure were magnesium.
The C6 ZR1 went out the door for around $104,000, but today they occasionally change hands for half that amount, making them one of the best performance car bargains of all time.