Personality Test

Is the Grand Sport Z07 a thinly veiled racecar, a steroidally enhanced Stingray for the street or something else entirely? We dispatch contributor Eric Gustafson on a grueling, two-part test drive to find out

September 21, 2017
Personality Test 1
Personality Test 2
Personality Test 3
Personality Test 4
Personality Test 5
Personality Test 6
Personality Test 7
Personality Test 8
Personality Test 9
Personality Test 10
Personality Test 11
Personality Test 12

We left San Francisco at 4:30 a.m. We’d signed up for a Hooked on Driving track day at Thunderhill Raceway Park 150 miles to the north, and the driver’s meeting started at 7:30. Our aim was to simulate an ideal day in the life of a C7 Grand Sport owner, one that included open roads, a closed race course and lots of driving. It seemed the best way to test our 2017 Chevrolet press car. We quickly learned that San Francisco, with its narrow, bumpy streets and near-constant fog-induced drizzle, is not the Grand Sport’s preferred habitat, especially when it has been fitted with the Z07 Ultimate Performance Package ($7,995). Thanks to its stiffer springs and semi-slick, track-ready tires, the Grand Sport sent our heads jostling from side to side and the traction-control light flashing. The need to make a U-turn revealed a laughably wide turning radius and cringe-producing tire rub. This seven-speed manual’s decidedly useful hill-assist feature was not enough to make up for its other urban shortcomings. After picking up photographer David Bush, we were happy to get this yellow-and-black beast out of Dodge.

It was still dark as we crossed the Golden Gate Bridge and headed north on Highway 101. With the sharp report of the smooth-revving LT1 V-8 still echoing off its walls, we emerged from the Robin Williams Memorial Tunnel full of excitement. Freed from the clutches of the city, we were taking the Grand Sport to a place where we were confident its virtues would reveal themselves, where its advanced engineering would shine—not just the racetrack, but great Northern California back roads. Yet even just being on the freeway was a big improvement: With the Driver Mode Selector knob in Tour mode, the Grand Sport’s ride quality approached a level of civility its poor inner-city behavior would not have suggested. Its ability to soak up the potholes created by California’s record winter rains surprised us. And with the engine hardly loafing in Seventh gear at 70 miles an hour, the Grand Sport’s cockpit is admirably quiet. Only the thrum of its steamroller tires (the rears are a whopping 335mm wide) and their occasional tramlining divulged this model’s track-oriented demeanor. The optional Competition Sport Seats ($2,495), though optimized for support, proved long-haul comfortable. As our drive came just two days after the Summer Solstice, first light was quick to appear on the eastern horizon, illuminating golden foothills in the distance and subtly hinting at the day’s forthcoming heat. We were, after all, heading into California’s Central Valley, which is not only the state’s bread basket, but its oven. The forecast for Willows, home of Thunderhill, called for a high of 106.

Thunderstruck

We made it in time for the driver’s meeting, though we had to hustle to get the Grand Sport ready for the first track session—affixing stickers, removing gear and hurriedly attempting to learn the new track layout. We’d driven Thunderhill on numerous occasions, but not since the addition of the West Circuit, which, when combined with the existing East Circuit, makes for a lengthy five-mile lap. Feeling a bit nervous, we decided to begin the first session with the Driver Mode Selector in Sport. We wanted plenty of electronic assistance while we learned the track. With its numerous tight corners, two blind crests and a nasty off-camber bend, the West Circuit is challenging. But the Grand Sport immediately proved a confidence-inspiring dance partner, thanks to its surfeit of grip, neutral handling and sophisticated driver-aid systems. While the LT1’s 460-horsepower output was enough to get us up to speed in a hurry, it wasn’t enough to make us afraid of inadvertently grabbing too much throttle. A C7 Z06, with its 650 horses, would have been far more daunting given our place on the learning curve.

After a couple of laps, however, we were ready to sharpen the Corvette’s responses and switched the Driver Mode Selector into Track. We wanted both less body roll and less electronic intervention. What we didn’t want was the steering wheel to suddenly become ponderously heavy, but that’s what we got. Other aspects of Track mode weren’t to our liking, either. Though the damping was noticeably firmer, the amount of driver and traction control seemed hardly diminished. We experienced too much intervention in a few corners, such as 3E, which, not unlike Laguna Seca’s infamous Corkscrew, involves a rapid drop after cresting a hill. We wanted power to help rotate the car; the computer wasn’t giving it to us, preferring to wait until the rear end was fully weighted.

When we came into the pits at the end of that first 20-minute session, our priority was to better calibrate the Grand Sport’s numerous settings. While it’s easy to bemoan its complexity, we couldn’t help but be impressed by the sheer adjustability of this machine. Thankfully, we figured out how to independently set the steering in its lighter-weighted Sport mode. Then, we went into Performance Track Management and selected Sport 1, the midpoint of five available levels of intervention. This mode still allows for some driver aid while giving traction control a fairly long leash. The Sport 2 and Race modes deactivate Stabilitrak completely. With that, we eagerly awaited our second track session—and watched the thermometer readout creep upward.

By 10 a.m., the ambient temperature had already climbed into the 90s. The C7 doesn’t have a perfect record when it comes to cooling issues on track. Automatic-equipped Stingrays have been known to overheat during high-performance driving events, and the same issue became enough of a problem on the C7 Z06 (both automatic and manual versions) that Chevrolet made some mid-cycle changes on 2017 models. While there was no reason to question the cooling system of our clutch-pedal-equipped Grand Sport, it would nevertheless be put to the test on this day. So would the brakes. The Brembos included in the Z07 package had performed admirably thus far, proving squeal-free and reassuringly powerful. The immediacy of the brake pedal is a bit startling at first, but we quickly adapted and actually came to find it surprisingly progressive. With massive cross-drilled, carbon-ceramic rotors (measuring 15.5 inches up front, 15.3 in the rear), huge six-piston calipers and trick alloy hats, the brakes look like they came straight off a Le Mans prototype.

Also from Issue 117

  • "COPO" L-79 C2
  • $10K Buyer's Guide
  • Restored '57 Fuelie
  • Supercharged C6 Grand Sport
  • Small-Block '68 Driver
  • History: Corvette vs. Thunderbird
  • Racing: Antonio Garcia
Buy Corvette magazine 117 cover