The mid-engine Corvette is 60 years in the making
GM’s worst-kept secret is that the eighth generation Corvette will have a mid-engine layout, enabling design, performance, and engineering that will rival the best of Italy’s supercars. To tide you over until the C8 appears on the show circuit in 2019, here’s a capsule history of past mid-engine experiments.
During a visit to Zora Arkus-Duntov’s home to pose a single question—Why were you so obsessed with mid-engine designs?—the Corvette’s patron saint confided that his inspiration dated all the way back to 1957, following the Corvette SS’s DNF at the 12 Hours of Sebring. “That’s when I concluded that the heat source [the engine] must be located behind the driver,” he said. Although the official explanation of the DNF was a failure of a rear suspension bushing after only 23 laps of racing, driver John Fitch’s feet were being cooked by the eight uninsulated exhaust pipes located in close proximity to the magnesium firewall and floor panels.
The inherent advantages of locating the engine near the middle of the car just ahead of the drive wheels were not lost on Arkus-Duntov. In the 1930s, he witnessed the mid-engine Auto Unions occasionally beat Mercedes-Benz racers with traditional powertrain layouts. Also, a mid-engine Cooper T43 driven by Jack Brabham showed promise at the 1957 Monaco Grand Prix.
So, when a new transaxle was under consideration at General Motors for use in 1960 mainstream models, Arkus-Duntov realized this component might be useful for a mid-engine, second-generation Corvette. Preliminary designs proved that forward visibility and center of gravity height would benefit from relocating the engine. Alas, a host of problems ensued, including cancellation of the transaxle’s production, halting the mid-engine C2 effort before it achieved critical mass.
That in no way discouraged Arkus-Duntov from nurturing the seed planted in his fertile mind. In 1960, to study the advantages of a mid-engine layout in a single-seat racer with Indy 500 potential, he gained approval to build what was dubbed a Chevrolet Engineering Research Vehicle (CERV). Key ingredients were a small-block V-8 ultimately tuned to produce 500 horsepower and an independent rear suspension that subsequently appeared in the 1963 production C2 Sting Rays. Tests were conducted at Pikes Peak, Riverside, Sebring, and Daytona Beach, and Arkus-Duntov topped 200 mph in CERV at GM’s Milford Proving Ground.
Unfortunately, GM politics at the time were adamantly against direct racing involvement, so CERV was “loaned” to a museum for display. Over the years, ownership was a matter of dispute. General Motors finally spent $1.32 million at last year’s Barrett-Jackson auction in Scottsdale, Arizona, to bring this family heirloom back to Michigan.
The 1963 CERV II followed in response to Ford’s GT40 international endurance-racing effort. A shorter wheelbase was achieved by moving the transmission from just ahead of the differential to behind it. A second transmission driven by the nose of the crankshaft and two torque converters gave CERV II all-wheel drive. Overhead-cam small-block and seven-liter pushrod big-block engines were prepared for this experimental vehicle, which ran to 214 mph during GM tests. The innovative driveline earned a patent, and Ferrari later adopted the layout for its 2011 FF GT (recently renamed GTC4Lusso).
Alas, CERV II development stopped when top management chose to support Chaparral cars in the Can-Am series instead of attacking Ford at Le Mans.
When Ford presented its mid-engine Mach 2 at the 1967 Chicago auto show to celebrate its epic Le Mans victory, GM’s design and R&D departments teamed up to create a credible response for the New York auto show. The engine was moved to a more fruitful mid-car location, and a sleek wrapper was sculpted for what the world would know as the Astro II. Road & Track featured this concept Corvette on its July 1968 cover, teasing readers with the notion that it was a street-legal Chaparral. Lacking a viable transaxle, the XP-880 Astro II died on the vine. GM’s R&D department joined the mid-engine party with that concept car built on lessons learned from the ill-handling XP-819 experimental car, which had its V-8 hung out the back behind a Pontiac Tempest transaxle.
With no help from Arkus-Duntov, but with the encouragement of GM design boss Bill Mitchell, Holden took up the mid-engine cause in Australia with its 1969 Hurricane concept. Equipped with oil-cooled front disc brakes (they resembled an automatic transmission’s wet multi-plate clutch and were inspired by similar equipment then in use on Detroit city buses), an early rearview TV camera, and a canopy lifted up and forward by servo motors, this right-hand-drive two-seater made noise with a 4.1-liter V-8 driving the rear wheels through a Holden-designed four-speed transaxle.
Exactly two years later, Road & Track swallowed the bait again, exclaiming, “We’ll stake our reputations on this being the Corvette of the future, but don’t expect it until 1972 at the earliest.” Code-named the XP-882 and billed simply as a Corvette prototype at the 1970 New York auto show, this Arkus-Duntov inspiration used a transversely oriented small-block V-8 and Olds Toronado transaxle components to provide drive to both axles. The patent granted in 1971 mentioned both manual and automatic transmission options. Even though the Ford-powered De Tomaso Pantera, the Mercedes-Benz C111, and the AMC AMX/3 mid-engine sports cars all bowed at the same show, Arkus-Duntov faced stiff resistance within GM. Unfortunately, Chevy boss John De Lorean had plans to drive the Corvette in a lower-cost direction, prompting the death of the XP-882 and Arkus-Duntov’s threatened resignation.
But better times soon followed. The XP-882 evolved into the XP-895 in 1972, with unibody construction and a freshened exterior. When the first prototype proved undesirably heavy, De Lorean convinced supplier Reynolds Metals to sponsor construction of an aluminum version that trimmed 500 pounds. But the spot-welding and adhesive-bonding techniques needed to construct the aluminum unibody were prohibitively expensive, resulting in another dead end.
GM’s brief rotary-engine romance yielded what many consider the most interesting mid-engine Corvette prototypes. The XP-897GT presented at the 1973 Frankfurt auto show incorporated an experimental 180-horsepower two-rotor Wankel under an attractive wrapper penned by designer Kip Wasenko. To shorten the build schedule, Pininfarina crafted the body panels over a Porsche 914 chassis. Arkus-Duntov had an even more ambitious idea. To double the power available, his team lashed together two rotary engines back-to-back. GM designer Jerry Palmer created a stunning exterior with a steeply raked windshield, split-folding gullwing doors, and digital instruments using early LCD technology.
When GM pulled the plug on its $50 million rotary-engine gambit, the 4-Rotor—it debuted at the 1973 Paris auto show—was given conventional V-8 power and re-christened the Aerovette. (Arkus-Duntov proudly showed me a scale model of this car, calling it his favorite mid-engine Corvette design.)
After Arkus-Duntov left GM in 1975, his passions weren’t forgotten. The mid-engine 1986 Corvette Indy was designed at GM, modeled in Italy, and constructed in England by GM affiliate Lotus with a wealth of advanced technologies, including a molded composite chassis, all-wheel drive, active suspension, four-wheel steering, electronic throttle, and a cockpit jammed with the latest navigation and display gear. The twin-turbo, 4.3-liter V-8 located just behind the cockpit was a variant of the Chevy engine supplied to IndyCar racers. Updated for the 1990 Detroit auto show and renamed CERV III, it was refitted with a twin-turbo, 650-hp version of the Lotus-designed LT5 5.7-liter DOHC V-8.
Although a mid-engine layout failed to make the cut for the 1997 C5 Corvette, engineers did detach the transmission from the engine, sliding it rearward nearly six feet to a location matching that in the original CERV, in unit with and just ahead of the differential. Since the rear wheels were also shifted rearward, the wheelbase grew from 96.2 inches to 104.6 inches, and there was minimal change in weight distribution. What chief engineer Dave McLellan sought here was a significant increase in torsional stiffness, achieved by adding a central backbone frame member in the space previously occupied by the transmission.
In his book Corvette from the Inside, McLellan devoted a dozen pages to mid-engine considerations over the years, noting that, in 1975, Arkus-Duntov urged him upon his retirement, “Dave, you must do the mid-engine Corvette.”
McLellan explained that Chevy’s sales department was against a mid-engine layout because it would diminish cockpit space and foster service headaches. His 1990 market research found that the Corvette faithful were not unanimously demanding such a move. He also feared that GM’s powerful design staff would likely jam the Aerovette’s gullwing doors down his throat, an arrangement that would eliminate convertible and targa body styles.
But, ultimately, McLellan was simply not a mid-engine believer. Nor was he interested in battling GM’s daunting political machine; in 1992, at the tender age of 55, he took early retirement, passing the chief engineer’s baton to Dave Hill, who had earned recognition at GM developing front-drive Cadillacs. Hill, a quiet but supremely capable engineer, stuck to the front-engine formula. His enthusiast credentials were sealed by the successful launches of the fifth- and sixth-generation Corvettes, not to mention the awesome Z06 edition for 2006. But his greatest contribution to the mid-engine cause may have been in 1993, when he hired as his assistant the open-minded Tadge Juechter, a soft-spoken, bicycle-loving lifestyle minimalist who is nonetheless a brilliant engineer devoted to making the Corvette the best it can be.
After the C6’s successful launch, Juechter quietly carried Arkus-Duntov’s mid-engine torch behind the curtains. According to interviews granted by his former bosses Tom Wallace and Bob Lutz, GM Design did its part by rendering a dozen or more full-size and scale models for consideration and wind-tunnel studies.
Cadillac’s Cien concept, which starred at the Detroit auto show in 2002, was another GM vote of confidence for mid-engine sports cars. Inspired by the F-22 Raptor stealth fighter and designed by Simon Cox, this stunning scissors-door two-seater brought two notable innovations: a body and chassis made of an ultralight aerogel material and a 7.5-liter, 750-hp V-12 with direct fuel injection and cylinder-shutdown capability. Clearly, Cadillac would love to offer an XLR successor as soon as a modern Corvette spinoff becomes feasible.
Instead of making the leap to mid-engine for the sixth-generation Corvette introduced in 2005, Hill’s engineers focused on improved handling and adding more power. The Z06 edition crammed 505 wild horses into a 7.0-liter pushrod small-block engine. Topping the 6.2-liter V-8 with an Eaton supercharger and intercoolers bumped maximum oomph to 638 horsepower for the 2009 ZR1. The new-for-2010 Grand Sport provided track-tuned brake and suspension equipment with a 430-hp, 6.2-liter V-8 engine.
After Dave Hill’s retirement in 2006, Juechter had little difficulty selling his mid-engine idea to the new chief engineer, Tom Wallace, an inveterate road racer. Product boss Lutz was at first skeptical of the seemingly radical move, but he, too, was convinced by Juechter’s logic. The three-man team then took their PowerPoint presentations to GM chairman Rick Wagoner, who granted the requested go-forth-and-conquer approval.
Unfortunately, Wagoner was soon distracted by a greater issue—the bottom falling out of General Motors. When the financial crisis hit in 2008, all Corvette development funds were canceled as part of a futile bid to avoid bankruptcy. When GM plunged into a government-assisted Chapter 11 reorganization, Wagoner, Lutz, and Wallace left the building. Juechter was left standing in a debris field while the feds dictated the company’s fate.
At least the Washington types realized the virtue of building and selling 30,000 or so highly profitable Corvettes per annum. Juechter’s work resumed on the seventh-generation Corvette for the 2014 model year. The timing wasn’t right for radical moves, however, and although the C7 emerged as the best-looking and –performing Corvette in ages, it carried on the front-engine, rear-transaxle layout introduced in the 1997 C5.
Work on a mid-engine C8 continued under deep secrecy. Although camouflaged winter test mules have been nabbed by spy photographers, they don’t reveal the next Corvette’s exterior details, because those cars were constructed with some of the body panels borrowed from Chevy’s Daytona Prototype racers.
Today it’s clear that tradition is essential to the Corvette ethos. But younger, more adventurous customers will be needed to keep the flame burning. A mid-engine layout will allow more possibilities, including special editions that will climb even higher up the performance and price scale, challenging Europe’s grip on the $100,000-plus sports car market, and a racing program that will keep pace with advancements in the sport. Although the C7 Stingray and its evolutionary descendants will surely live on for several more years, the mid-engine C8 will soon arrive to give Corvette customers a second choice. The new Vette might keep the internal code name Zerv, as a show of respect to Zora Arkus-Duntov and his seminal CERV experimental cars.