Callaway Chevrolet Corvette SC606

Callaway Chevrolet Corvette SC606 Callaway Chevrolet Corvette SC606
Specialty File

Callaway Cars got off  the ground in the garage of founder Reeves Callaway—whose father launched the Callaway vineyard and, later, Callaway Golf—where he was building turbo kits for the BMW 320i in the mid-1970s. But ever since its sanctioned-by-GM, twin-turbo C4 Corvette launched to great acclaim in 1987, the company has mostly stuck with modifying Chevy’s sports car.

Callaway’s latest C6 Corvette offerings add an Eaton TVS2300 Roots-type supercharger, starting either with the base car’s 6.2-liter LS3 or the Z06’s 7.0-liter LS7 V-8. For $21,395, the LS3-powered SC606, such as this one in new-for-2010 Grand Sport trim, is fed 7.0 psi of boosted air and jumps to 606 horsepower and 553 pound-feet of torque, gains of 176 and 129, respectively.

But Corvettes aren’t exactly hurting for power, and a bigger reason this car caught our eye is Callaway’s optional seats that replace the Corvette’s much-maligned units—and they’re phenomenal. With wraparound support and without sacrificing comfort, they remind us of those found in Porsche’s Boxster Spyder and hard-core RS cars. Only these, which start as Recaro shells that are skinned by Callaway to accommodate the Vette’s narrow seat wells, go a step further by retaining the power adjustability and heating capability of the stock Corvette seats. GM, if you’re listening, please, please, give Callaway a call and figure out a way to mass-produce these gems. Hopefully that would cut the cost to something a bit more palatable than Callaway’s ­current $8970 option price, too.

You’ll thank yourself every day for ordering the optional seats, which rival Porsche’s finest. Callaway’s interior upgrades, including the chunky Alcantara-and-leather-covered steering wheel, are among the best we’ve seen from the aftermarket.

The company also has a fix for another of our Corvette beefs: rear-end skittishness over midcorner bumps. To remedy this, check the box for the $5760 suspension package, which adds adjustable Eibach coil-overs and remote-reservoir shocks to supplement the Corvette’s stock transverse-composite-leaf-spring setup, along with new front and rear anti-roll bars and a 0.8-inch-lower ride height. It all makes the Corvette feel far more secure and planted, even over the rough stuff, although the ride is noticeably firmer (but not excessively so). And, although Callaway makes no tweaks to the steering, the chassis changes contribute to more linearity in the way  the effort builds. The end result is one of the most neutral Corvettes we’ve driven, with near-perfect cornering balance and the ability to effortlessly rotate the car under power.

Beyond solid advancements in these areas, however, the Callaway struggles to improve upon the performance of factory Corvettes—cars that, let’s not forget, have impressively kept their weight in check and produce test results that are anything but easy  to improve upon.

Case in point: skidpad grip. Our car had Callaway’s $4950 package consisting of OZ wheels wrapped in the Michelin PS2s from the top-dog ZR1. While the Callaway achieved an astounding 1.07 g on the skidpad, that’s no better than a Z06 or ZR1 on these tires and just 0.01 g ahead of the latest Grand Sport when equipped with the new Goodyear F1 Supercar G:2 tires.

The story repeats itself in the chapter on acceleration. While certainly no perform­ance slouch—0 to 60 happens in 3.5 seconds, and the quarter-mile drops in 11.7 at 125 mph—the Callaway is no quicker than the last Z06 we tested, partly because it’s 251 pounds heavier. This doesn’t seem like a great use of funds for a coupe—upgrading from a Grand Sport to a Z06 is just a few grand more than the price of Callaway’s supercharger package—but a key Callaway selling point is that this level of perform­ance, unlike the hardtop-only, manual-only Z06, is available also for the convertible or with an automatic (as many as 70 percent of its customers choose the latter). Manual buyers can opt for a seriously short-throw shifter ($490), although the effort increases accordingly, and shifts still can’t be rushed..

Regardless, the Callaway is extremely polished, with exceptionally smooth power delivery. In fact, jump on the throttle once rolling—as in our 5-to-60-mph test—and, as long as the tires are warm, there’s no wheelspin whatsoever. But banging on the throttle does make the supercharger—slathered in $1100 of powder-coated finish in our case—flinch noticeably under its beautiful carbon-fiber shroud (“like sitting backward in a GT40,” remarked one of our staff). And looking at how  the weave continues unbroken over the hood’s slats makes it easy to see why Porsche, Mercedes, and Audi all source carbon-fiber bits from Callaway.

Unfortunately, the speed doesn’t come with much bombast from the so-called “double-D” exhaust. Above 3000 rpm, it’s eerily silent for a 606-hp V-8; so subdued that the blower’s light whine, normally concealed by engine noise, becomes the primary soundtrack. And despite the quietness at high revs, it drones significantly at about 2000 rpm, which is—annoyingly—right where the engine settles in during 80-mph highway cruising.

Something that definitely didn’t need fixing is the brakes—particularly on Grand Sport models, which inherit the Z06’s larger hardware—but, nevertheless, Callaway has a $9820 package that replaces the rotors and calipers with beefier Stoptech units. The good news is that they’re larger and have more heat capacity, which should extend their on-track capability. And in our 70-to-0 braking test, the Callaway performed identically to the ZR1, at 142 feet, which is the shortest-stopping production car  we’ve ever tested. This isn’t entirely surprising, though, considering the shared rubber. However, the Callaway’s brakes switch from the regular Corvette’s multipad setup (six pads per front corner, four per rear) to a more traditional two-pad-per-corner setup, which the company claims is both lighter and wears better. The problem is that it suffers from significant knock-back—this is when hard cornering causes slight flexing that pushes the pads away from the rotors—so when going for the brakes in the Callaway, there is sometimes a huge whoa! moment as the driver pushes through an initially  limp pedal until the slack is taken up.

Another thing that usually makes us wince is tuning shops’ interior modifications, but the Callaway bits, though expensive, are first-rate. The Alcantara-and-leather-covered steering wheel ($3590) adds some much-needed pizazz—the Vette’s stock  wheel looks and feels like a clone of  the lowly Malibu’s—with contouring at the nine and three positions, as well as a flat-bottom carbon-fiber piece. And the leather on the dash totally shames the stock trim.

To keep the price out of  loaded-ZR1 territory,  as was our $118,905 test car, skipping some of the pricey options—particularly the brake upgrade—is advisable. But for Z06-grade acceleration with a choice of body styles and transmissions, the Callaway makes a decent case for itself. Just make sure to get the seats.

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Callaway Cars Incorporated, 3 High Street, Old Lyme, Connecticut 06371; 860-434-9002; www.callawaycars.com