FORCED REDUCTION
Jeff Glenn looks at the Callaway C16 supercar's more discreet and less expensive counterpart, the 2008 Callaway Corvette. Studio photography by Callaway's own Scott Williamson; other images by Reeves himself.
The first Callaway-tweaked Corvette is one of the most memorable: With factory endorsement and its own RPO code, the original C4-based Twin Turbo was clearly a step apart from other tuner-built machines. Typically equipped with distinctive Dymag wheels, special hood ducting, and bespoke aero pieces, the Twin Turbo is often the first car that comes to mind at the mention of the word "Callaway."
After the Twin Turbo was dropped from the lineup after the 1991 season, Callaway continued producing Corvette-based performance packages and complete hotrods. Notables include pumped-up, normally-aspirated "SuperNatural" versions of the LT1 and LT5 V8s, a handful of purpose-built competition machines, and the radical Paul Deustchman-designed C12 supercar.
Callaway wasted little time applying its magic to the sixth-generation chassis, offering the 550-horsepower SuperNatural C6 in 2005. Without any forced-induction assistance, the car scorched the quarter-mile in less than 12 seconds, offering Z06-like performance in stealthy standard-C6 clothes. For buyers seeking something more eye-catching, Callaway followed the SuperNatural C6 with the rebodied, supercharged C16. Available in coupe, convertible, and chopped-windshield Speedster form, the C16 was a natural successor to the C5-based C12 exotic.
With the C16 established as the flagship of its lineup, Callaway has now turned its attention back to subtler creations. Combining the low-profile aesthetic of the SuperNatural C6 and the forced-induction engine treatment of the C16, Callaway's latest high-performance offering is a C6-based machine simply called the Callaway Corvette.
Though the Callaway Corvette initially seems like a fairly straightforward tunercar, the affable company founder Reeves Callaway quickly points out that building a modern hotrod is not without its challenges. "Over the past 20 years, there have been increasing expectations related to emissions, fuel economy, and warranty length." Though horsepower-obsessed tuners might be reluctant to face these practical requirements, Callaway and a few other speed merchants have faced them head-on. "For example," Reeves muses, "the supercharger people weren't asleep while the concerns about practicality increased. The efficiency of this late-model Roots-type compressor has pretty much blown everything that came before it away."
Armed with the latest in supercharger technology, the Callaway Corvette provides much more punch than the stock C6 without significantly affecting the standard car's civility. Indeed, Callaway's creation isn't so much a from-scratch special as it is a narrower interpretation of the starting theme.
For $18,500 on top of a new C6, the Callaway Corvette includes a 122 cubic-inch Eaton/Magnuson supercharger, an intake-manifold-mounted air-to-liquid intercooler, an in-house Callaway Honker cold-air intake, high flow fuel injectors, a signature Double D exhaust system, and a 50-state-legal remapped PCM. Nestled beneath a custom-fabricated hood, all of that hardware helps the LS3 powerplant develop a Z06-beating 580 horsepower and 510 lbs-ft of torque.
Though Callaway has plenty of experience with exhaust-driven turbochargers, Reeves was drawn to the packaging advantages offered by the Eaton blower. Fitting nicely in between the V8's cylinder banks, the supercharger provided a more compact installation than traditional side-mounted turbos. Even more attractive was the reliability of the Eaton blower: "We tested every supercharger on the market, and only one made it to the 100,000 mile mark," Reeves explains. "The Eaton was the only one that passed the test. Now we know why so many OEM carmakers are using the Eaton—it's the only one that will hold up over the long haul." Though the blower is mounted atop an internally stock LS3, and adds well over 100 horsepower to the motor's standard output, Callaway is confident enough in the durability of the system that it backs the install up with a three-year, 36,000-mile warranty. Callaway's experience with the Eaton/Magnuson supercharger has been so positive that the firm has agreed to become the exclusive source of these blowers for Corvette applications.
Many of the tweaks applied to the 2008 Callaway Corvette are familiar pieces from the firm's well-respected performance catalog. The CAD-sketched Honker air intake, for example, was developed for the LS2, but proved to be a good match for the supercharged application. Previous lessons learned in the areas of exhaust design and engine-management programming were also applied to the new model—as the most recent summary of the company's extensive tuning experience, the Callaway Corvette is more highly developed than the average tunercar.
The car showcases just enough stylistic changes to separate itself from the standard C6 without significantly changing its underlying Corvette identity. The hood and wheels are the most obvious visual updates. Says Reeves, "The bulge in the middle of the hood was originally designed to be a separate piece. The hood was going to close down around it like a shaker, but from a structural point of view it made the hood too floppy. So we designed a one-piece hood that is more structurally sound, but still contains a break between the lines of the bulge and the lines of the hood. We also learned that if the hood and bulge are the same color, it looks awful—it needs some contrast. Now, when you look at the car from the side or front, you can easily imagine that the bulge is a separate piece."
The standard wheels are alloy versions of the carbon/magnesium Dymags fitted to the Callaway C16, and they exactly match the sizes and offsets of their more exotic equivalents. That means 19x9.5-inch front rollers wrapped in 285/30-19 skins, and chunky 20x11 rears with 325/25-20 rubber bands. Rounding out the basic package is a collection of Callaway badges, body-color valve covers, and full manufacturer documentation.
Though the $18,500 price tag covers the main highlights of the Callaway Corvette package, the company does offer a lengthy list of optional upgrades, many of which were fitted to the demonstration model seen here. First on the option list is the Multi-Pro suspension system, which was developed in conjunction with Eibach. Though the Multi-Pro setup retains the stock transverse leaf springs, it adds a Callaway/Eibach coilover shock assembly at each corner. The coilovers are installed in place of the stock dampers—instead using a plain shock tube, Multi-Pro incorporates a threaded damper tube with a light-duty coil spring wrapped around it. "The suspension that comes in the production automobile is a terrific compromise," Reeves explains. "The whole strategy of using a composite spring placed low in the car that never wears out, is very lightweight, is corrosion-proof, is silent, and isn't fighting for real estate with any other suspension component is a really good solution. The trouble is that serious enthusiasts like to have some control over the suspension. So, we left all of the standard componentry in place for all of the good reasons I just listed, plus we found a way to add a supplemental spring at each wheel that only accounts for the increase in spring rate over stock." Once that foundation was set, Callaway turned its attention to the dampers. "There are four or five companies that make great racing shocks," Reeves continues, "but most of them have no clue what it takes to make a road shock that lasts 100,000 miles." Eibach offered the needed durability in racing-style double-adjustable dampers with separate controls for bump and rebound. "We provide a suggested starting point at the middle of the range and let the owner adjust for specific road conditions from there." A set of upgraded antiroll bars and a precision four-wheel alignment completes the Multi-Pro setup, which retails for $5960 fully installed.
A set of C16-spec Dymag carbon/magnesium wheels are a direct bolt-on, but they don't come cheap—figure about $10,000 for a full set. For discriminating enthusiasts, says Reeves, the wheels are worth their significant cost: "They weigh 40 percent less than even the best alloy units. Imagine coming home, taking your business shoes off, and putting on your sneakers. There are two major things at work—there's the increased ease of accelerating and decelerating an object with reduced rotational inertia, and there's the reduced strain on the hardware which has to control the mass way out on the end of the suspension arms. These wheels really make the whole car feel significantly lighter."
Our photo car was also equipped with $7620 worth of StopTech braking hardware, and a set of Callaway-branded sport seats that sell for just under $7000. Though the demo car's various options add up to a healthy $30,000 or so, that still does not test the limits of what the Callaway Corvette can be. Carbon-ceramic brakes, close ratio transmissions, custom differentials, and a host of track-specific tidbits can also be added.
Though Callaway Corvettes do not carry factory RPO codes, they will be sold through select Chevrolet dealerships. The cars, which can be built in coupe, convertible, manual or automatic forms, will be built at the three Callaway facilities in Old Lyme CT, Irvine CA, and Leingarten, Germany. All three factories are capable of building a complete car in two days—that schedule should easily fulfill a planned 2008 run of 400 units.
Inevitably, comparisons will be made between the Callaway Corvette, the factory Z06, and the new 620-horsepower ZR1. Since the basic $18,500 package still slots the Callaway well beneath the ZR1 in terms of price, the Z06 provides the most direct competition. Well aware of potential debates between his car and the Z06, Reeves is confident that his creation more than stands up to the factory's naturally-aspirated hotrod. "Our car offers more power, and a more pleasant way of delivering it. The supercharger helps the engine progressively pull harder and harder all the way to redline. You never feel like you come up to a peak and then drop off the other side. It's really pretty thrilling—if you're in third or fourth, and you're willing to take it to wide-open throttle, you'll be going really, really quickly."
Further separating the Callaway Corvette from the factory Z06 are the full-convertible and automatic-transmission options. Explaining the decision to offer those extra choices, Reeves quips, "We know how picky the Corvette owner is. If he isn't, he should be." With power, equipment flexibility, and warranty confidence, the Callaway Corvette is a compelling addition to the C6 landscape.