1990 Chevrolet Corvette ZR-1 - King Again

415 Cubes And 610 Horses Make This'90 ZR-1 A Royal Rush

Chris Endres Mar 1, 2009 0 Comment(s)
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Long-suffering Corvette performance enthusiasts had their loyalty tested for most of the '70s and the first half of the '80s. Ever since Big Brother stepped in and pulled the plug on the performance party in Detroit, practically nothing of real interest had rolled off the assembly line. Finally, in 1985, the L98 Tuned Port Injection engine became available. Though not exactly a return to the halcyon days of such fire-breathing mills such as the big-block LS6 454 or the high-revving, solid-lifter LT1 small-block, the TPI proved a capable performer, and when paired with the nimble C4 chassis, it was a giant first step back in the direction of performance.

In the spring of 1988, rumors started swirling about a return to true high performance in the Corvette camp. The car in question was to be called the ZR-1, and it would benefit from an unprecedented engineering effort aimed at elevating the Vette to the status of genuine world-class performer. Though still a high-school student at the time, Houston radiation oncologist Sanjay Mehta knew he wanted a ZR-1 from the moment he saw the first spy photos of the new model. "I sat in study hall, reading car magazines, dreaming of the day I would own one," he says. Word of an engineering collaboration with Lotus certainly piqued his interest, as it did for even the most casual of Corvette observers. As it turned out, the fruits of this project were to be unlike any engine previously installed beneath the car's long composite hood.

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No turbo, no blower, no joke-this engine makes its power the old-fashioned way: lots of cubes and lots of revs. The big 415 regularly sees 7,500 rpm.

The new engine, dubbed the LT5, shared the same displacement as the familiar small-block 350, but that's where the similarities ended. Based on an aluminum block and cylinder heads, the engine featured four valves per cylinder and four overhead camshafts. The advanced combustion-chamber design allowed an unheard of (for the time) compression ratio of 11:1. The LT5 was so smooth, it was claimed a nickel could be stood on edge on the intake manifold and remain standing while the engine was started.

One of the more ballyhooed features of the new ZR-1 was the "valet key." A separate key inside the cockpit could be switched between normal and performance modes. The idea was to limit unauthorized joy rides in the new super-Vette. The LT5 intake manifold featured separate runners and injectors for each of the sixteen intake valves, two per cylinder. This system was only active during spirited driving, and disabling it with the valet key substantially reduced peak power production.

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Sanjay Mehta selected a timeless set of Fikse FM/5 wheels, wrapping them in sticky Nitto rubber.

With all the runners active, though, look out! The LT5 churned out 375 hp at 5,800 rpm and 370 lb-ft of torque at 4,800 rpm. This was enough to hurl the portly (3,520 pounds) ZR-1 through the quarter-mile in 13.4 seconds at 109 mph. All LT5 engines were hand-assembled at the Stillwater, Oklahoma, plant of Mercury Marine before being trucked to Bowling Green for installation in the ZR-1 chassis.

While the engine got the majority of the attention, the ZR-1 chassis was no slouch, either. Featuring the cockpit-adjustable FX3 suspension, it had three settings to allow the driver to maximize the car's performance under different driving conditions.

The car was soon dubbed "King of the Hill" by GM insiders, and the press was quick to adopt the sobriquet. Had Chevy gotten it wrong, this unofficial title could easily have blown up in the company's face. Thankfully, this wasn't the case. Not that many nonenthusiasts noticed. Despite its brawny performance, the ZR-1 wasn't exactly a head-turner.




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