When I arrived at the circuit in the morning, the parking lot was already full of Corvettes—Callaway and otherwise—including two ZR1s. I’d never seen so many supercharged C6s gathered together in one spot; the amount of horsepower corralled in the paddock was truly staggering, with one of the Callaway Z06s packing over 700 horsepower under its heavily vented carbon-fiber hood.
Little time was wasted in unleashing all those ponies. After a few words from Harchelroad and MPH’s amiable head honcho, George Anderson, we were let loose on the track. Officially, we were to maintain a “parade-lap pace,” but the grin with which that phrase was uttered seemed to suggest more speed would be allowed. Before I could climb into the driver’s seat of the red 2011 Grand Sport coupe I had chosen to test drive, I was informed that a local hot-shoe driver was on hand to provide me with some orientation laps. Red carpet, indeed.
Hughes got right to work. The Corvette felt absolutely planted through the 2.2-mile track’s 14 corners, exhibiting hardly any body roll. Though the car wasn’t being pushed to the absolute limit, I was still glad for the sports seats, as I was being held in place with a sense of security that the standard Corvette seats simply cannot afford. Interestingly, Hughes much prefers this car’s handling to that of his ZR1; he finds the latter simply too soft for serious track work, even with the shocks set in their sport setting.
With the number of cars on track and the varying skill levels of their drivers, Hughes was only able to really uncork the engine a few times, but when he did, the Grand Sport accelerated with near-ZR1 intensity. My, what a difference an extra 176 horsepower makes. Though audible, the whine from the Eaton TVS2300 supercharger is fairly muted; the glorious roar from Callaway’s low-restriction exhaust system leaves a more lasting impression. If the supercharger specification sounds familiar, that’s because it’s the same one found on the ZR1’s 638-horsepower LS9 engine. Considering the fact that Callaway’s $21,395 SC606 package is a fully warranteed (three-year/36,000-mile), bolt-on affair—it includes a liquid-to-air intercooler, high-flow fuel injectors, a high-volume fuel pump and a cold-air intake—its 32-bhp deficit is entirely understandable.
Before heading out, the two main questions on my mind were: How would the stock Grand Sport suspension and brakes handle the significant increase in horsepower? And second, how would the automatic transmission perform in concert with the supercharged engine? I was fairly confident that the Grand Sport underpinnings were up to the challenge; after all, they are nearly identical to those found on the 505-horsepower Z06. As for the transmission, I had my doubts. I’ve driven other supercharged C6 automatics, including a Callaway C16, in which the gearbox and the engine seemed to speak different languages. Admittedly, these cars featured early examples of Chevrolet’s paddle-shift transmission that were slow to heed commands.
It took me only a few corners to discover that Chevy’s automatic and Callaway’s SC606 package make a fine pairing. Left to its own devices, the transmission performed well, holding gears long enough to enjoy the full breadth of the supercharged engine’s powerband. However, I wished the transmission would downshift more aggressively in full automatic mode. For this reason, I much preferred using the paddles on track. My pushes and pulls were met with rapid up- and downshifts.
When it came time to scrub off speed, the Grand Sport’s Z06-spec brakes were up to the task, providing rapid retardation and solid pedal feel. The pedal remained firm throughout my time on the track, but I wouldn’t want to subject the brakes to repeated hot laps, especially with the standard brake pads.
As for the suspension, I’m pleased to report that it performed admirably. Sure, the car exhibited a bit more lean in the corners than the coil-over-equipped Grand Sport, but the handling balance remained pleasingly neutral. The additional weight of the supercharger and its related hardware doesn’t cause understeer to rear its ugly head; the car still turns in with satisfying immediacy.
Knowing that Harchelroad Motors was still looking for a buyer of this untitled Grand Sport—its Harchelroad-applied white stripe atop the optional Callaway C16 hood should appeal to Nebraska Cornhusker fans—I headed into the pits. Right on my tail was a white Grand Sport convertible. The car had loomed increasingly large in my rearview mirror during my last lap; its driver obviously knew his way around the circuit and wasn’t afraid to hammer his Callaway.
That driver was Scott Bartels, who had driven out from Lincoln, Nebraska for the day. Bartels is a longtime Corvette enthusiast, and a serious C4 afficionado. To finance the purchase of his new Grand Sport, he sold off four of his C4s. The one he kept was an ’87 Callaway twin turbo, the second B2K-optioned car ever made. The idea of owning the original Callaway Corvette offering and the latest appealed to Bartels. “I wanted to own the alpha and the omega,” he said.
Part of a Callaway Corvette’s appeal for Bartels is the fact that “it’s not mainstream.” He said that most people aren’t familiar with the brand. Another factor influencing his purchase was the fact that he could get a high-horsepower Corvette convertible with an automatic transmission—a combination that Chevrolet doesn’t offer—while still having a warranty. Of course, the Callaway’s performance was a big factor, too. “You’ll run out of guts before you run out of car,” he enthused.
Over the course of his first nine months of trouble-free ownership, Bartels says that the Callaway Grand Sport has renewed his enthusiasm for the Corvette hobby. “I had stepped back, big time,” said the formerly active club member. Since purchasing the car, he’s completed a driving school at MPH and returned to the track on a monthly basis. “I get treated like family out here,” said Bartels.