08-20-2008, 12:34 AM #1
Fire starter: First drive of the 638-hp, track-shredding Corvette ZR1
Fire starter: First drive of the 638-hp, track-shredding Corvette ZR1
The story goes that back in 2001, as the Corvette team outlined its expected price and performance figures for the $70,000, 505-hp Chevrolet Corvette Z06, General Motors boss Rick Wagoner wondered whimsically how much performance GM could offer in a car that cost $100,000.
Wagoner wasn’t the only one pondering the big-money question. As the previous-generation C5 changed the Corvette from a “get what you pay for” buyer’s compromise into a world-class contender, even harsh critics admitted that it was no longer only the choice of the budget-limited who really wished they drove a Porsche 911. The feeling grew with the first tests of the even more refined, even faster C6 in 2004. And when the Z06 hit the track in 2005, it was difficult to ask for more.
Three years later, the sun scorches pavement on a 90-degree July day at GM’s Milford, Mich., proving grounds. ZR1 chassis-dynamics engineer Jim Mero, the hot shoe who &%$#@-smacked the vaunted Nürburgring Nordschleife with a lap of seven minutes, 26 seconds, nonchalantly drives us on a few track-orientation laps . . . in a Chevy Tahoe Hybrid. Not exactly a good indicator of where to brake and turn a ZR1 around the Milford Road Course, a quick three-mile layout of endless elevation change, blind apexes and fast off-camber corners that offers neither tire barriers nor vast expanses of paved runoff area. Mero points out spots where we are most likely to wad up the $105,000 Corvette now resting in the paddock.
Dip the pedal to disengage a new, higher-strength twin-plate clutch, and press the start button. The ZR1’s supercharged 6.2-liter LS9 V8 fires with all the drama of tea time at a crocheting club. The engine hums sedately at idle--no shimmy, no shake, no overcammed, flame-spitting rage. Select first gear from the ZR1-specific close-ratio six-speed Tremec transmission. The pedal effort and shifter action feel so similar to the Z06’s (perhaps even lighter) that you might think you’re driving one.
A yellow ZR1 blasts onto the front straight, engine belting out a unique note. Foot to the floor and head encased in helmet, you don’t hear the supercharger’s whine as the LS9 peaks in first gear--at 66 mph. Bang the shifter into second, then third a blink later as the short braking zone for turn one arrives. The experience is surprisingly serene. The car is stupid fast, but the power delivery is smooth enough to render acceleration far from frightening, especially if you have Z06 experience. But if instrumented tests set to come later this year prove Chevy’s cited numbers correct, the ZR1 will officially claim residence in the surreal zone.
With 638 hp at 6,500 rpm and 604 lb-ft of torque at 3,800 channeled through the first close-ratio gearbox in Corvette history, Chevrolet says 0 to 60 mph happens in 3.4 seconds, 0 to 100 in 7.0. The official top speed is 205 mph, although Corvette chief engineer Tadge Juechter deadpans that the car is electronically limited to 210 mph, because of “social responsibility” concerns, when, in theory, it could hit 215.
To understand the ZR1’s accelerative prowess, skip past ubiquitous stock supercars such as the Porsche 911 Turbo or the Lamborghini Gallardo. Instead, line up your ZR1 on the drag strip opposite superexotics with no fear. With 1 hp per 5.20 pounds, the ZR1’s power-to-weight ratio stacks up favorably against exotics from Porsche (5.01 pounds for Carrera GT; 5.98 for 911 GT2), Dodge (Viper, 5.75), Lamborghini (Murciélago LP640, 5.8 without fluids; Gallardo LP560, 5.99) and Ferrari (F430 Scuderia, 5.91).
Consider: AutoWeek’s 2004 metered test of the Carrera GT produced a 3.50-second 0-to-60-mph time, a 7.06-second 0-to-100-mph run and an 11.35-second quarter-mile at 129.5 mph. Juechter says Chevy’s tests have produced 11.3-second quarter-miles at 131 mph, putting the ZR1 right on the money with a universally lauded megacar costing more than four times as much.
Our Carrera GT acceleration and braking data say that the Porsche theoretically could do the 0-to-100-to-0-mph deed in 11.60 seconds. The ZR1? Juechter reaches into his data bank and extrapolates a ludicrous 10.25. In both cases, the real figure would be a tick higher because of the time needed to move your foot from throttle to brake. Call it less than 11 seconds. Call it insane.
The ZR1 demands a huge commitment before you can even begin to think you have reached its limits, but when you do, the chassis sucks big g forces out of the pavement--so big, in fact, that the seats shared with the Z06 are inadequate, with average side bolstering at best. Juechter says the ZR1 will maintain 1.05 g in steady-state cornering, and you feel every bit of the load as it moves you around.
The adjustable magnetic ride-control suspension offers two modes, touring and sport, and while touring mode works on the track, sport’s added shock damping results in quicker response to steering input while tightening up the already well-controlled body motions. But the car is far from boring or too easy to drive, as mid-corner throttle modulations move the chassis around, and you never lose sight of the fact that you are dancing with the devil when pushing hard at high speed.
The best Corvette steering yet helps you analyze and react to what the car is doing. Chevy improved all 2008-model-year Corvettes by adopting a new steering-gear machining process and a stronger intermediate shaft. For 2009, it has added a standard, mechanically variable system that changes the ratio from 17.1:1 to 14.6:1 as you wind on lock; compared with the Z06’s 2.78 turns lock-to-lock, ZR1 requires 2.54. GM’s road course is glassy smooth and void of the mid-corner imperfections that in the past have caused drivers to wish for more direct feedback, but you still feel that much of the previous system’s vagueness is gone, adding to the confidence needed to throw the car around at speed.
Cresting hills fast into braking zones, the Brembo carbon-ceramic brakes--15.5 inches front, 15.0 inches rear--slash speed as well as any road-car system on the planet. The brakes are derived from the setup used on Ferrari’s Enzo and FXX, with the rear discs the same size as the Enzo’s fronts, while the fronts are four millimeters smaller than the FXX’s because of ZR1 wheel-clearance issues and a GM-specific monoblock caliper. The brake pedal is firm and progressive, and there is none of the grabbiness or high sensitivity to initial pedal pressure that plagues some carbon-ceramic setups, allowing precise modulation at any speed. Hammered nonstop, the brakes show no sign of fade or reduced performance. And while some carbon-ceramic brakes are loud and annoying when cold or during street driving, the Brembos never make a sound, even during a short public-road stint in another ZR1 that was never used for track duty.
Certainly, you won’t ever call this anything but a man’s car, but it will make driving heroes out of mere boys at anything short of the outright limit. And for the brave souls who do push to 10-10ths, each owner receives a spot in a high-performance-driving school as part of the $105,000 base price (which also includes the car’s $1,700 gas-guzzler tax).
The ZR1 takes on an entirely different character as you drive out of the proving grounds and onto public roads. The one-inch hood bulge that accommodates the supercharger and associated hardware is obvious from inside the cockpit but does not interfere with sightlines. On the road course, your eyes always look far down the track at the next corner, so you don’t realize that you can see down through the polycarbonate window that exposes the top of the supercharger. On the street, you notice the window instantly, as you do the supercharger boost gauge (max boost is 10.5 psi) in both the instrument cluster and the digital head-up display.
When you’re helmet-free, the whine of the Eaton supercharger is obvious. As you tip into the throttle, it combines with that signature V8 bass to create an almost bizarre engine note that is part high-strung European, part small-block American. Lift off the throttle, and the two-mode exhaust’s internal flaps stay open slightly longer than do the Z06’s to release a loud popping familiar to anyone who has ever stood trackside as Corvette Racing’s C6.R enters a braking zone.
And yet the ZR1 meanders along leisurely and quietly at 45 mph in sixth gear, just as easily as it smoked the Milford Road Course. Potholes come and go, absorbed easily by a suspension set to touring. By using the magnetic system, engineers were able to set the ride frequencies between those of the base Corvette and its optional Z51 performance suspension. But with large 33.3-millimeter front and 31.0-millimeter rear antiroll bars, the ZR1 maintains almost identical roll stiffness to the Z06, providing the best balance of performance and comfort in the entire Corvette lineup.
Another of the magnetic system’s advantages is that it improves drag-strip launches by recognizing the ZR1’s low speed and the driver’s demand for loads of torque. In that situation, damping firms up to cope with high launch forces, then softens again over a 10-second period when it calculates that the tires have hooked up and sent you screaming away.
The most fun, though, comes at the very end of our test, when powertrain integration engineer Luke Sewell climbs aboard the car on a long Milford straightaway and--efficient launches be damned--performs some of the most righteous burnouts imaginable. As smoke billows from the ZR1’s custom-designed Michelins through the neighboring woods and out onto a nearby road, a concerned motorist dials the GM switchboard: “Something’s on fire inside the proving ground!”
This article was last updated on: 08/19/08, 23:48 et