The 2005 Chevrolet Corvette C6 gets a new bod, new threads, and 400 horsepower--and that's just for starters By Todd Lassa Photography by Wesley Allison Motor Trend, 2004-02-01 00:00:00 Don't believe your eyes. This car may look like the current Corvette with fixed headlamps, but it's an all-new interpretation of the Classic American Sports Car. Actually, Chevrolet's engineers and designers have changed a lot of things you can see--and, more important, many more you can't--in a comprehensive, if not total, redesign. For starters, its new Gen-IV LS2 V-8 makes 400 horsepower in base form. The 2005 sixth-generation (C6) Corvette is five inches shorter than the C5 and within 0.1 inch of its longtime street and track rival, the Porsche 911. And the interior has finally climbed above rental-car-level quality and materials. The whole treatment creates a global sports car designed to appeal to Corvette traditionalists and successfully woo conquest buyers who've previously chosen Euro hardware. How substantial are the nips, tucks, and organ transplants? "You could put all the parts [carried over from the C5] in a bushelbasket," says Dave Hill, vehicle-line executive for Corvette and XLR and just the third chief engineer in Corvette's history, after Dave McLellan and Zora Arkus-Duntov. Hill promises higher revs and better ride, handling, and brakes that serve up international dynamics to match its new international proportions. Is it convincing? We can't speak for the dynamics--yet. But this reveal details the car's design, engineering, and powertrain. C6 Design Though the C6 may cost less than half of the $100K Mercedes-Benz 500SL, the devil is still in the details. If the panel alignment on this prototype is any indication, the C6 may just be the most beautifully assembled Corvette ever. The outside door handles are hidden and operate electrically. Chief Designer Tom Peters reinterpreted the curvilinear Corvette profile with a look that suggests "a Coke bottle designed by Picasso." Front and rear fenders arc down at the doors, with a complicated inverse shoulder line connecting them midway through the doors. The side cove is big and pumps up the car's muscularity, and the jet-fighter canopy is body-colored, with a B-pillar that leans back; on the C5, it slants forward. At launch, only one body style will be offered: a hatchback with a single, removable roof panel. The convertible roadster variant will make its public debut at the Geneva Auto Show in March. After more than 40 years of disappearing headlamps, a Corvette with flush-glass lighting will take some getting used to. Peters notes that "there was a lot of internal commotion about this, and the decision to go or not go with fixed headlights was nearly 50/50." Some feel they're cleaner and more modern; others disagree, citing them as busy and perhaps strangely shaped. Without question, they are mechanically simpler. Though the C6 may cost less than half of the $100K Mercedes-Benz 500SL, the devil is still in the details. If the panel alignment on this prototype is any indication, the C6 may just be the most beautifully assembled Corvette ever. The outside door handles are hidden and operate electrically. Note the cross-drilled rotors and functional fender vents of the Z06. High-intensity Xenon high- and low-beam headlamps reside under a clear plastic cover, allowing a "flash-to-pass" feature for European markets. Front fenders kick up at a sharper and taller angle from the hood, compared with the C5, making the tops of the fenders more prominent from the driver's seat, like a 911's. Brake-cooling inlets are hidden, from the bottom of the front bumper in the C5 to the underbody in the C6, for better airflow and to prevent front-end lift. Hidden door handles--like on the Cadillac XLR, the C6's chassis cousin--have a matte-charcoal vertical accent stripe that makes them easy to locate. The matte look repeats in a lip spoiler on the tail that incorporates the center high-mounted stoplamp. The C6 uses the XLR's keyless entry and ignition: keep the key fob in your pocket and hit the ignition button. A hidden key system backs it up in case of electrical failure. Side glass is indexed, so when you touch the electrical connection under the door handle, the glass powers down slightly to unseal it from the roof. This makes a tighter seal, and Hill promises no window "blowout" up to 180 mph. Like the C5, the C6 has a bubbletop roof contour, but now it's more distinctive. The hatch glass tapers more sharply into what Hill calls a boattail (shades of the 1971 Buick Riviera and, of course, the original Sting Ray). A drainage system channels rain water away from the luggage compartment when the back hatch is opened. The C6's tail is tightened and horizontally creased midway from top to bottom, but it still looks huge. Its taillights go back to a rounder, typical-for-Chevy look, and four chrome exhaust tips are enclosed in a lower valance. Much has been done to address criticism of the C5's cheesy interior. On the C6, the lighter of its two-tone colors extends three-quarters of the way up the doors, and more liberal use of the seat color throughout is designed to make it feel more spacious. The unloved "membrane" power-window controls are replaced by conventional black plastic ones, and black interior trim has been replaced by lustrous ebony. Seats have power lumbar and power side bolsters, with airbags built into the sides. And the doors sport side pockets, with a "hold on!" vertical grab-handle for the passenger. Like the Cadillac XLR, the C6 has power-button interior door releases in place of handles. The C5's two "fairly lousy" cupholders (Hill's description) are replaced by a covered two-cup compartment next to the shifter. The instrument cluster features white LEDs and high-contrast needles. The coolest interior feature is the new head-up display, which has a tach dial with two track modes and alternatively displays directions from the optional DVD-navigation system. The tach/track modes display a rev-counter meter, with a digital readout of speed underneath and lateral acceleration in g. Neat stuff. Overall, the interior is clean and businesslike, if not dazzling. It's light years better than the C5's, in terms of design and materials quality, and makes the C6 a lot nicer piece to drive or be driven in. Engineering As predicted in our April 2003 cover story, the architecture of the Corvette is new and yet remains similar to the C5 in layout, materials, and assembly. This evolution of the Corvette formula makes for a more-compact, stylish, potent, and still relatively affordable premium sports car. "We weren't out to fix what wasn't broken or to reinvent the wheel," Hill says. "On the other hand, 85 percent of the car's mass and 70 percent of the part numbers are new." The new car's chassis consists of a hydroformed steel frame with robust side rails of tubular steel and a highly rigid box-section central tunnel. The tunnel, with its bolt-on closeout panel, contributes to the car's torsional rigidity and, with the rails, adds to the car's bridging strength. This frame is designed to be stiff and shudder-free, despite the open-top design. It's reportedly beefy enough to handle serious suspension loads generated by high speeds and impressive levels of tire grip. Compared with the C5, the C6's wheelbase has been stretched from 104.5 inches to 105.7. But the overall length of the car has been trimmed from 179.7 to a more athletic 174.6, thanks to shorter front and rear overhangs. A Porsche Carrera is 174.5 inches overall and rolls on a 92.6-inch wheelbase. The Corvette still outweighs the Carrera by roughly 100 pounds, but the flat-six Porsche serves up only 315 horses, so the Vette maintains a worthwhile power-to-weight advantage. The removable polycarbonate and magnesium roof is bigger, but lighter, than the C5's roof panel. Three latches hold the lid in place, and it stows neatly under the rear hatch. Hill says there's now more stowage area under the roof when it's removed and fitted under the glass hatch. The rear composite tub is stouter and designed to keep the car quieter and improve its overall solidity. An extruded structure, aluminum and magnesium welded and adhesively bonded, is bolted to the front of the fabricated-steel passenger compartment and provides the uprights for the door hinges, the swoopy windshield frame, and the instrument panel support. Passenger and driver seats are again bolted through floor panels made of steel sheet and balsa wood. Hill insists these offer outstanding noise, vibration, and recyclability benefits. Suspension, Steering, Brakes Attached to the main ladder frame at the nose and tail are cast-aluminum subframes to which the aluminum A-arm front and rear suspensions are bolted. These subframes are also the platforms for the transverse composite leaf springs. Most of the new suspension hard parts are shared with the XLR, and the suspension travel is up 13mm in front, 20mm in the rear. GM tunes it for a cushier ride in the XLR, while the Vette driver can put "the power down earlier in corners for higher exit speeds at a track," Hill enthuses. The C6 has three suspension levels: base FE1, F55 (with electronic dampers), and the firmer Z51 set up for racing weekend-warriors. The base suspension is designed for better grip and ride than that exhibited by the previous car. The magnetic selective ride-control suspension offers Sport and Tour settings, like the current Corvette. Hill says the differences between those settings have been dramatically increased for the C6. If you can't wait for the 2006 Z06, the Z51 offers stiffer springs, higher-rate anti-roll bars, larger Sachs dampers, and more aggressive tires. This firmer package will be offered on coupes and convertibles. With the 400-horse engine standard, you can nearly match C5 Z06 performance levels in top-down form, Hill contends. Controversy surrounds the C5's magnetic-variable-assist steering. Some drivers like it. Some say it's too light and uncommunicative. Hill says the C6 has a retuned version of the C5's rack-and-pinion system repositioned forward in the chassis to accommodate the longer Northstar V-8 in the XLR. The new system also has eight-degrees more caster for better "on-center feel and precision." The turning circle is less than 40 feet to pass the European standard. Don't fix it if it ain't broke. Although 70 percent of the C6's part numbers are new, according to Dave Hill, the new Vette's basic layout remains the same: a front midship-mounted high-output overhead-valve V-8, rear-mounted transaxle, aluminum A-arm suspension with transverse leaf springs, magnetic variable-assist steering, and monster disc brakes. The real magic, however, is how all these pieces work together. Big four-wheel discs with standard anti-lock stop the car. Rotors are cross-drilled on the hotter Z51, mostly for a "performance look"--Hill admits it doesn't give the brakes much of a performance advantage. The massive brakes communicate with the pavement through a set of Goodyear Eagle F1 "extended-mobility" run-flat tires, because space for a spare and jack is gone. Hill claims the third-generation run-flat tires are quieter, have greater ride compliance, and offer a more aggressive footprint. Powertrain Forget those old proposals for turbine and rotary-powered Corvettes: Chevy has wisely stuck with, and continues to improve, the small-block pushrod V-8. Latest is the Generation-IV, all-aluminum engine with cast-iron liners, its displacement bumped from 5.7 liters in the Gen III/LS1 to 6.0 liters in the new LS2. The new engine makes a fat, square 400 horsepower (up from 350) and 400 pound-feet of low-rev torque and yet spools to a lofty 6500 rpm. It packages neatly into the same space as the LS1 but shaves 15.4 pounds. Stroke remains 92mm (3.6 inches). The bores are hogged out to 101.6mm (4.0 inches) from 99mm (3.9 inches). The compression ratio is up from the LS1's 10.1:1 to 10.9:1 in the LS2, putting additional squeeze on the intake charge to improve brake-specific fuel consumption. Powdered-metal forged connecting rods spin on a cast nodular-iron crank. On the breathing side, Hill reports a 30-percent cut in restriction. Valve sizes are unchanged at 2.0 inches for the intake and 1.6 for the exhaust, with no fancy sodium fill for the stems. The deeper breathing comes from intake-manifold improvements and a hotter cam with greater lift. On the exhaust side, system backpressure is down 10 percent and the spent gas now flows out through thin-wall cast-iron manifolds. This reduces noise, relative to the former fabricated-steel units. Engineers have (so far) dismissed Displacement on Demand for the LS2, reportedly after resonance problems with the Vette chassis made it obvious the car was running on four cylinders. Besides, GM says customers are happy with the C5's fuel economy--Motor Trend managed nearly 30 mpg on long trips--and the extra cylinder shut-down hardware adds valvetrain inertia that would cut the engine's rev capability. But one insider reports that a DOD C6 in early trials netted 35 mpg on the highway. The Tremec T-56 six-speed manual is a carryover transmission, and the automatic gets upgraded from the 4L60E in the C5 to the 4L65E, with its higher torque capacity, in the C6. Alas, it's still a four-speed and offers neither multiple shift modes nor any sort of manumatic control, although the latter is still under consideration. Last month, we incorrectly anticipated use of the XLR's five-speed automatic or even a six-speed unit, but Hill says it can't handle the output from the LS2. The manual gearbox's linkage effort has been improved for shorter stick and wrist-flick ratio changes. The automatic sports a better version of the company's performance algorithm shift system. This reportedly allows the automatic box to intelligently hold lower gears through twisty road sections for better dynamic control. Bottom Line So there you have it: the details on Chevy's red, white, and blue sports car--now with a dash of Eurostyle thrown in. GM is walking a tightrope by going after the 911 customer while trying to please and retain its traditional base. We have a lot more to analyze before we declare the C6 a winner or loser: We'll have details on the new convertible soon, that all-important first drive and track test are pending, as is the next Z06. We'll say this much: A trimmer, more powerful C6 should make for a more maneuverable, more fun car to drive. Some traditionalists will embrace the new look, others may not. But with 400 horses on tap in the base car, everyone will have a lot to like in the 2005 Corvette. ---- POWERTRAIN/CHASSIS Drivetrain layout Front engine, rwd, 2-door coupe Engine type 90° V-8, alum blk/hds Valve gear OHV, 2 valves/cyl Bore x stroke, in/mm 4.00x3.62 / 101.6x92.0 Displacement, ci/cc 364.9 / 5970 Compression ratio 10.9:1 Max horsepower @ rpm 400 @ 6000 Max torque @ rpm 400 @ 4400 Specific output, hp/liter 67.0 Power-to-weight, lb/hp 8.11 Max engine speed, rpm 6500 Transmission 6-speed manual or4-speed automatic Suspension, front; rear Upper and lower control arms, transverse leaf springs, anti-roll bar; upper and lower control arms, transverse leaf springs, anti-roll bar Brakes, f;r 13.5-in vented disc; 12.5-in vented disc, ABS Wheels, f;r 18x8.5; 19x10.0cast-spun aluminum Tires, f;r 245/40ZR18; 285/35ZR19 Goodyear Eagle F1 GS run-flat DIMENSIONS Wheelbase, in 105.7 Track, f/r, in 62.1 / 60.7 Length, in 174.6 Width, in 72.6 Height, in 49.1 Curb weight, lb 3245 Weight dist, f/r, % 51/49 Cargo capacity, cu ft 22.4 Fuel capacity, gal 18.0 CONSUMER INFO On sale in U.S. June 2004 Base price $47,000 Airbags Dual front, front-side Basic warranty 3 yrs/36,000 miles Powertrain warranty 3 yrs/36,000 miles EPA mpg, city/hwy (est) 19/28 (man) 18/25 (auto) Range, city/hwy (est) 342/504 (man) 324/450 (auto) Recommended fuel Unleaded premium ----- Corvette Credentials, A guide to the history of the Corvettes from the C1 through the C5 C1 1953: First Corvette bows with 150-horse six and automatic trans, at $3498. 1955: Thanks to Zora Arkus-Duntov, Corvette gets 195-horse 265-cubic-inch V-8. 1956: Body design gets first major revision; adopts "side cove" look. 1957: Fuel-injected 283-cubic-inch, 283-horse V-8, four-speed manual options. 1958: New quad-headlight nose, fake front fender cove strakes, longer, wider body. 1961: "Ducktail" rear-end styling, part of minor facelift, portends C2 Sting Ray. C2 1963: New, shorter, trimmer Vette with standard IRS, pop-up headlamps, 360-horse L84 option. "Sting Ray" name and Z06 performance package appears. First and only year of split-window rear glass on coupe 1965: Four-wheel disc brakes replace four-wheel drums. Big-block V-8 arrives with 396-cubic-inch, 425-horse L78 option. 1966: 427-cubic-inch big-block option added, with 390 or 425 horsepower. C3 1968: New Corvette body, originally scheduled as a 1967; shares chassis with C2. 1970: 454-cubic-inch big-block replaces legendary 427. 1973: Power nosedives: Engines are 190- and 250-horse 350-and 275-horse 454 (ratings now SAE net). 1975: First Vette since 1964 with no optional engine. First use of catalytic converter and HEI electronic ignition. Last C3 convertible. 1976: Convertible dropped, at least for now. 1978: Glassback body style replaces hardtop.Special Pace Car and Silver Anniversary editions. 1983: Corvette production skips a year; a few cars built, but never sold. C4 1984: Completely revised design is trimmer in all but track and overall width. The 205-horse V-8 is carried over from 1982 Vette. 1985: Tuned Port Injection (TPI) replaces dual throttle body Crossfire system. Firm Z51 handling option offered. 1986: ABS is standard. Ragtop returns as Pace Car replicas. 1989: Six-speed manual gearbox replaces previous 4+3 overdrive unit. 1990: Lotus-engineered, Mercury Marine-built 375-horse twin-cam, 32-valve LT5 V-8 offered in ZR-1. 1995: Final year for ZR-1 (LT5 rated at 405 horsepower). 1996: 330-horse LT4 V-8 offered. Available Grand Sport and Collectors Edition models. C5 1997: Fresh design on new, longer, hydroformed perimeter frame. All-new LS1 V-8 makes 345 horsepower. 1998: C5 convertible debuts. 1999: Corvette hardtop body style joins lineup. 2001: 385-horse Z06 bows, offered as hardtop only. LS1 climbs to 350 horses. 2002: Z06 gets a bump to 405 horsepower. 2003: 50th Anniversary Edition. Optional Magnetic Selective Ride Control. 2004: Commemorative Edition coupe, convertible, hardtop, with Z06 featuring C5-R paint scheme and carbon-fiber hood.