Heavy Metal - 1995 Chevrolet Corvette ZR-1 GT1
In the mid-1990’s the endurance racing world was busy recovering from a devastating seismic shock. Dubious engine Formula One-inspired regulation changes and deliberate mismanagement had swiftly killed off the wildly popular World Sportscar Championship at the end of the 1992 season, leaving a gigantic hole in its wake.
The WSC had exclusively used purpose built prototypes divided over two classes. Group C1 provided a stomping ground for major manufacturers looking to reach the 400 kph mark, whereas Group C2 housed much cheaper naturally aspirated machines meant for plucky privateers. With the WSC’s collapse these specialized machines disappeared into corporate museums and obscure national championships, often after losing their roofs. With the prototypes gone outside of Le Mans, the focus shifted to GT-racers. Following this shift the international BPR Global GT Series was created in 1994, cementing the GT-car’s place at the center of endurance racing.
Within the power vacuum left behind by the demise of the WSC, the BPR Global GT Series quickly gained a foothold as the single most popular endurance series on the planet. Initially it brought together single brand cup racers from the likes of Porsche and Venturi, but not long after specialized machinery started showing up as ambitious privateers entered the fray.
Major manufacturers started taking note of the series’ explosive expansion as well. With the old Group C prototypes there had been very little marketing potential for them, as the cars could only resemble road going models by name and a lousy stickered-on grille. GT-racing on the other hand utilized lightly modified versions of established halo cars, making it a very interesting tool for promoting a brand.
One such brand was Chevrolet, or more specifically, the Corvette. Throughout the energy crises of the late 1970’s and the dreadful over-regulated smog-obsessed 1980’s, the Corvette had slowly but surely lost any and all credibility as a legitimate sportscar. Its mighty V8-engine had been strangled and choked to nearly below 200 horsepower, and the predominance of woeful slushbox automatics meant it didn’t appeal to anyone outside of triple burger country.
This all changed drastically in 1990, with the introduction of the hair-raising Lotus-tuned C4 ZR-1. The ZR-1 was the most advanced Corvette up to that point, featuring a bespoke DOHC, 4 valve per cylinder, variable intake, all aluminium 5.7L LT5 V8. Moreover, the car exclusively featured a 6-speed manual gearbox, adaptive ride control and later traction control. With 375 and later even 405 horsepower, the ZR-1 was the fastest American production car money could buy, and with GM-subsidiary Lotus heavily involved, it went around a corner pretty neatly as well.
Although the ZR-1’s success and cultural impact was immense, one man still wasn’t entirely satisfied. Corvette Challenge racer and tuner Doug Rippie had seen the ZR-1 and its new LT5 motor, and concluded it had massive unlocked potential. While attending the 40th Anniversary Corvette Show in 1992, Rippie met Gary Cline, Project Engineer for the LT5 project at Mercury Marine, the marine engine company Chevrolet had selected to build the exotic engines.
Rippie and Cline started chatting away, and found they had a mutual agenda in trying to make the engine even faster. As a result Doug Rippie was hired on to work with Mercury Marine and Lotus engineers to do just that. Their combined efforts resulted in a special series of engines, the DRZ-500. These generated as much as 475 horsepower in road legal spec, and 525 in full race spec. The savage units quickly became known as Black Widows, named for their distinctive black paint and red wires. Distribution and fitment of the engines was handled by Rippie himself through a company set up for just that purpose: Doug Rippie Motorsports.
Although content with his new business, Rippie still had something on his mind. As an avid Corvette racing aficionado, he wanted to do nothing more than to beat the established brands at the greatest GT-race of all, the legendary 24 Hours of Le Mans. Sadly, he didn’t really have the money to do it. To make ends meet he set up the ZR-1 Corvette Team USA non-profit corporation, hoping to bring in sponsors from the Corvette community.
Rippie counted on support from Mercury Marine and Lotus engineers, and eventually finished two fully operational chassis. The Corvette’s slender body had been buffed out considerably, and an extensive aero package was fitted including a distinctive large hoop spoiler. In addition the car’s trademark pop-up headlights were thrown out to save weight and aid aerodynamics. Instead a large battery of lights in the front bumper was used.
Under the hood the DRZ-500 had been bored out to 6.3L, and had gained two massive turbochargers. Through these means power was brought up to a grand total of 575 horsepower. The extra grunt was channeled through a strengthened 5-speed manual gearbox by Weisman, powering the rear wheels
Because the small outfit lacked the funds to rent an entire racetrack for testing, the decision was made to enter the brand new ZR-1 into the 12 Hours of Sebring. The bumpy former military airfield was notorious for breaking cars apart, so anything wrong with the Corvette would show itself instantly. Driven by Bill Cooper (USA), Scott Maxwell (CAN) and Chris McDougall (CAN), the car did just that. Sebring’s harsh road surface shook the car apart, and the trio was out early with mechanical issues.
For Le Mans, the ZR-1 would face some titanic opposition. The popularity of the BPR Global GT Series had by now reached stratospheric heights, as more and more highly capable machines showed their face at La Sarthe. The 1995 edition of the race featured one of the biggest GT fields seen in decades, making Doug Rippie’s job that much harder.
Among the barrage of European GT1 weaponry were the Porsche 993 GT2 Evo, Lister Storm GTS, Aston Martin DB7 V8 and the Venturi 600 LM. Adding insult to injury, two formerly fastest cars of the world were present, the Ferrari F40 GTE and the Jaguar XJ220, complemented by the current fastest car of the world, the McLaren F1 GTR.
Besides the continental scourge, the Corvette had to fence off a four-pronged attack from the Far East, consisting of the Nissan Skyline GT-R LM, Toyota Supra GT LM, Honda NSX Turbo and the exotic SARD MC8-R homologation special
Luckily the unproven machine managed to at least qualify for the race, which was on its own a terrific achievement. More worryingly, the big red Corvette set a dismal time in the hands of John Paul Jr. (USA), Chris McDougall (CAN) and James Mero (USA). The car was obviously far over the minimum 900 kg weight limit, and its power figure was less than impressive.
Front running GT1 machines like the F1 and F40 were making well over 600 horsepower, a figure the unproven Corvette simply could not reach safely. In the end the home-built monster qualified 48th and dead last overall, a full eleven seconds behind the slowest Callaway Corvette competing in the lower GT2-category. The Corvette’s immense incompetence was further illustrated by the incredibly quick GT1-polesitter. The Ennea SRL Ferrari F40 GTE had set a blistering time of 3:55.090. This was a dizzying one minute and twelve seconds faster than the ZR-1 had managed, and good enough for 6th place overall.
The car’s performance then, was less than admirable. Still ZR1 Corvette Team USA was in relatively good spirits. They had made it to the promised land of Circuit de La Sarthe, and despite all their inexperience and lack of resources they would be allowed to start. Furthermore, the team had fitted a new engine for the race, as their first had been losing compression after the Le Mans Test sessions.
On race day however, the team noticed the same problems with the second motor. The V8 was losing power at an alarming rate, so the car was brought in for another extensive rebuild. As the regulations required cars to finish with the same engine block as they started with, another straight swap wasn’t on the cards. Instead the remains of the first engine were scavenged to complement the first, and the big bruiser was sent on its way again.
The jerry-rigged engine seemed to do the trick, as the Corvette steadily but still very, very slowly racked up the laps. Despite its terrible pace and questionable reliability, the car outlived much of the field into the night. Sadly the story came to an end just three hours before the finish, when the MacGyvered DRZ-500 finally gave out. In one fell swoop the team’s hope of reaching the finish was blown away, along with most of the engine’s internals.
The Chevrolet Corvette ZR-1 GT1 was a gung-ho project by an enthusiastic amateur. Doug Rippie was great at building a street legal rocketship out of an under-performing sportscar, but had very little experience in the realm of professional GT-racing at the highest level. His club racing experience did very little to prepare him for the technological savagery of GT1.
This lack of experience lead to him building an underfunded, overweight, underpowered behemoth with no chance of taking the fight to the big guns. The ZR-1 GT1 was one of the most technologically advanced Corvette’s up until that point, which perhaps made it far too complex for its traditionally-minded American handlers. This complexity would ultimately prove to be its downfall, as the experimental engine failed to survive long enough on any occasion. In the end, the Corvette ZR-1 GT1 goes down in history as another tragic case of overbearing blind ambition.