In a Corvette ZR1 I was given the fastest lap I've seen at Road America, the 4.05-mile-long, 14-turn and very fast road-racing circuit near Elkhart Lake, Wisconsin. I was riding along on a shakedown lap with John Heinricy, Corvette assistant chief engineer and a race driver of some note. Later that day
I drove the same car for several memorable laps but was well off Heinricy's torrid pace--and without showing nearly his level of panache. That was 1995.
At GM's recent media introduction of 2009 models, Heinricy colleague Jim Mero took me on some hot laps in the new supercharged, 6.2-liter, 638 hp ZR1 Corvette. By contemporary standards the 405 hp 1995 ZR1 was quick. In comparison its 2009 namesake is blindingly fast, particularly for a street- and emissions-legal sports car that runs on pump unleaded premium. A 5.0-liter Jack Roush Trans Am Mustang team car I tested at Road Atlanta several years back didn't feel nearly as quick, despite being nearly 900 pounds lighter and running on race slicks.
Some 3.4 seconds' worth of first-gear acceleration will see 60 mph from rest; the quarter-mile mark flashes past in 11.3 seconds at 131 mph. The last Corvette C6 ZO6 I drove, with 505 hp from its 7.0-liter LS7 engine, covered the 0-60 sprint in 3.7 seconds and quarter mile in 11.7 seconds at 125 mph. Those few tenths of a second may sound inconsequential, but in a two-hour race it can separate the winner from a distant back-marker. And the gap widens even further in the upper speed ranges.
One difference between the previous Corvette top dog, the ZO6, and the ZR1 is apparent even to bystanders. Eyes closed, anyone with normal hearing can readily tell the two apart. For that matter, so can those suffering from incipient deafness. At wide-open throttle the 2009 Corvette ZR1 rushes past with a gut-punching, visceral shriek of supercharger whine and hammer-heavy exhaust blast. A ZO6 is loud at WOT but almost demure in comparison, and it lacks the distinctive, soaring alto note from the hard-working, four-lobe Eaton supercharger.
On the race track, their style of power delivery is equally distinct. Despite its smaller displacement and with an additional 170 pounds to motivate, the Corvette ZR1's LS9 V-8 has substantially more power on tap from 2500 rpm to its 6600 rpm redline. A wafer-thin air-liquid intercooler is mounted above the engine, lowering charge air by some 140 degrees. The resulting hood bulge, though almost imperceptible from a distance, is one of the few visual distinctions between the Corvette ZR1 and the Corvette ZO6. More obvious are the massive vents in each fender to extract hot air from the engine compartment.
On the Bondurant School of High Performance Driving road course near Phoenix, Arizona, Chevy engineer Miro needed even less rowing of the beefed-up Tremec six-speed than is needed in the already torque-laden Corvette ZO6. Using the Peterbilt-like 604 lb-ft of grunt, instead of a three-two downshift to accelerate through the flat-out left-right kink, the Corvette ZR1 could be short-shifted instead, relying on its huge swell of torque to negotiate the corner in third. It was like that everywhere on the course.
Not surprisingly, the ZR1 receives useful upgrades to accommodate the power infusion. Brake diameter grows from the ZO6's already-substantial 14.0 inches to 15.5 inches in front. (The wheels on the car I drove to the track that day were smaller in diameter than the Corvette's front rotors.) Total brake-pad real estate at each front corner is double that of the Corvette ZO6's already-massive 70 square centimeters.
Brake rotors are a special Brembo ceramic silicon-carbide design, reinforced with carbon-fiber material for low mass and high resistance to heat and wear. The ZR1 at the media event circled the track scores of times at race speeds, hammering the brakes repeatedly on the tight track, with no apparent distress. Other than a brief cool-down after each trio of maximum-G laps between passenger pickups, no special measures were taken to pamper the brakes. Driver Jim Mero said he noticed no fade during the ZR1's five non-stop hours of track duty. And Chevrolet says the rotors good for the life of the vehicle.
Magnetic Selective Ride Control suspension, optional on the base Corvette and unavailable on the ZO6, is standard. As on other GM vehicles, these shocks deliver surprisingly compliant ride motions while holding tight rein on body roll. The tail can readily be rotated under braking or power but like the ZO6, the ZR1 fairly begs for a long-radius curve or a straight to put down its retina-detaching level of power.
The ZR1's handling appears to be fairly neutral, an observation confirmed by Miro. Michelin Pilot Sport 2 run-flats, size 285/30ZR19 in front, 335/25ZR20 in the rear and developed specifically for the ZR1, are given much of the remaining credit for the ZR1's more benign handling qualities. They're mounted on new 20-spoke alloys, also ZR1-specific.
Inside, the familiar cockpit is little changed from that of the Corvette ZO6. Other than a boost gauge and digital boost readout in the head-up display, there are few visual clues to differentiate the two. Subtle ZR1 logos are to be found on sill plates and headrests.
Two variants are available. The RPO 1ZR, base-priced at $105,000, gives you the standard ZR1. Tick the $10,000 RPO 3ZR option and you get heated seats, side air bags, Bose sound system, nav system and leather on the dash. Only two other options are available: chrome wheels ($2000) and paint upgrades ($300 to $750). That's it.
Mindful of future collector value, Corvette ZR1 models carry a unique VIN plus a sequential build number. For instance, a ZR1 with a VIN ending in -0150 would signify that it was the 150th ZR1 built that model year. Nice to know when you're buying the least-expensive supercar on the planet.
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