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Illustrated Corvette Series No. 23 - 1964 CERV II -
"Chevrolet Engineering Research Vehicle"
CERV II was Zora Arkus-Duntov's most exotic experimental car. Like the CERV I, this car was built with one thing in mind, competition.
For many years, Duntov's little rocket car held the Milford Proving Ground track record with an average speed of 206 mph! With short gearing, the CERV II would run 0-to-60 in 2.8 seconds. With Duntov's patented 4WD power train, the car wanted to be driven faster!
The original plan was to build six cars, three for competition and three spares. The construction of the car was truly ahead of its time. Some of the advanced features included four-wheel drive using a Powerglide torque converter for each end of the car, side-mounted fuel cells, a monocoque frame, low profile Firestone racing tires, and a 377 cubic-inch all aluminum V-8 using Hilborn injection, single overhead cams, making 500 horsepower.
The body was styled by Larry Shinoda and Tom Lapine. Unlike the Grand Sport, the CERV II was stable at speeds over 200 mph. It only needed a small spoiler on the rear deck. The wheelbase was only 90 inches, front and rear tracks were 53.5 inches, making the CERV II a short, wide car.
Jim Hall and Roger Penske both liked the car's unique handling and driver's position. When pushed to the limit, the CERV II would go into a very fast, flat spin. Much of the CERV II's technology was later used in the Chaparral 2D.
In 1970 a ZL-1 engine was fitted into the car for some "tire testing." Later, in 1989, the car was valued at over $1.5 million. All I can say is those dragster headers must have sounded awesome! - K. Scott Teeters
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lIlustrated Corvette Series No. 42 - 1964 XP-819
"Experimental Rear-Engine Corvette"
Car companies make prototype cars all the time. Most of these machines are never shown to the public. Corvette prototype cars often become very high-profile machines. Only a few were never shown, for good reason. The XP-819 was an engineering study used to prove a point concerning the correct direction for future Corvette development.
The XP-819 was the result of a clash between Zora Arkus-Duntov and engineer Frank Winchell, who'd been involved with the Corvair project. Winchell contended that you could make a balanced, rear-engine, V-8 powered sports car by using an aluminum engine and larger tires on the rear to compensate for the rear weight bias. Duntov adamantly disagreed. A loose design was drawn that received some very unflattering comments from Duntov and Dave McLellan. Winchell asked designer Larry Shinoda if he could make something beautiful with the layout, to which Shinoda told him that a tape drawing could be shown after lunch. Shinoda and designer John Schinella sketched out the basic shape shown here. Duntov asked Shinoda, "Where did you cheat?"
It didn't look "too bad", so a working prototype was ordered. Shinoda supervised the styling and Larry Nies' team of fabricators built the car. In only two months the XP-819 was on the test track.
It turned out that Frank Winchell's theory about rear-engine, V-8 cars didn't work out very well. However, Shinoda's design was well received. They were obviously into the "shark thing" and picked up styling points from the Chaparral cars. It even had wheels from a Chaparral.
This car was definitely a Corvette, even though the back end was big. Unfortunately, with all that weight behind the rear axle, it was only a matter of time before it crashed during a high-speed lane change test. The question of stability was answered, and the XP-819 was send off the the scrap bin...almost.
Oddly enough, GM sent the car to Smokey Yunick's shop in Daytona, Florida. The chassis was cut in half and usable parts were removed. What was left was stored in an unused paint booth as just "old junk." Years later, a Corvette collector was buying some parts from Yunick and offered to buy the junked XP-819.
So the pile of car scrap was rebuilt and finished as a streetable car, like a kit car. A cast-iron V-8 was used in place of the original all-aluminun engine. We're talking serious rear weight bias here. It's quick and now does awesome wheelies! - K. Scott Teeters
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lllustrated Corvette Series No. 35 -1968 Astro I Mid-Engine Experimental Corvette
Almost from the beginning, there have been those at Chevrolet who wanted the Corvette to be "something else." Along the way there have been proposals to soften the Corvette, add a back seat, and to use steel for the body. The Astro I proposed using an opposed, flat-six, Corvair engine. Fortunately, this was one for the history books.
The official purpose of the Astro I was to study aerodynamics and new features. Engineers had long known that frontal area and shape were major factors in how slippery a car is in high-speed air. Much of what we take for granted in aerodynamics was new territory in the mid '60s. For this study, function followed form.
To keep the front profile as low as possible, a modified, flat, opposed-six Corvair engine was placed behind the rear wheels. Although a far cry from the rip-snort'n 427s of the day, the little 176 cubic-inch enginewas made of alloy aluminum with steel cylinder sleeves and featured single overhead cams, hemi heads, Weber carburetors, and made 240 horsepower. That's 1.4 hp per cubic inch!
The unibody construction had large boxed side sill members that added stiffness as well as housing a fuel cell on the passenger side. The bulkhead behind the driver and the forged aluminum windshield header provided rollover protection.
The front and rear suspension used double wishbones and four-wheel disc brakes. Wheels and tires hadn't gotten fat yet, so 5.5 inch and 7.0 inch wheels were used front and back.
Note the absence of any normal door lines. The entire canopy hinged up from a pivot point behind the rear wheels. Since the car was 35.5 inches tall, 12.3 inches shorter than a '68 Corvette, the seats were fixed to the canopy and actually raised up so that you could step into the interior. This was not a rainy day car.
The Astro I had many styling tricks that were standard for GM study cars; a closet at the base of the windshield for wipers, pop-up spoiler brake lights, access panels on the hood for servicing fluids, and periscope rear view mirrors. The interior had the gauges, warning lights, and twin-grip steering control device. Trick stuff in 1967.
At only 35.5 inches tall, the Astro I was as low as a Countach, 15 years earlier. Too bad it wasn't packing a 427. Oh well.
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lIlustrated Corvette Series No. 36 - 1968 Astro II Mid-Engine Experimental Corvette
Almost from the beginning, racing has made the Corvette a living legend. Sports car development in the 1960s was explosive, and at the cutting edge was the Ford GT40 and the Chevrolet-backed Chaparral, both using a mid-engine layout. The Astro II (XP-880) was the first of several experimental, mid-engine Corvettes that kicked off years of exotic sports car anticipation.
Ford started the race by first offering a street version of their GT40, called "Mark III" and then by unveiling the "Mach 2" experimental mid-engine car in May 1967. Designers at Chevrolet went right to work on their own version of a mid-engine Corvette. After 11 months, the Astro II was shown, immediately initiating a blizzard of speculation asking the question, "Is this the next Vette?"
By using off-the-shelf parts, the designers were able to deliver the car quickly, and at a relatively low cost. However, because of a lack of serious commitment by Chevrolet, the car was made using an out of production, '63 Pontiac Tempest, two-speed transaxle. Ford, on the other hand, had a race-proven, four-speed manual gear box for the Mach 2. The big question was, if pushed into production, would a two-speed automatic Corvette be taken seriously. Probably not.
Despite its built-in design weakness, the Astro II was a very interesting effort. It certainly looked exotic and screamed "Corvette" with its body styling. The Astro II used a central backbone frame and thick doors that housed safety beams. The 20-gallon fuel cell was located in the center of the frame. The engine, suspension and drivetrain were all attached to the central frame. With a 427 engine, this made the car more like a Can-Am racer than a street car. Even with production Camaro and Corvette suspension parts, and performance street tires, the Astro II generated 1.0 g of cornering grip. This was part of the magic of a mid-engine sports car. Astro II weighed in at 3,300 pounds, 300 less than a production Corvette, yet had almost the same external dimensions.
While the Astro II was being track tested in Spring 1968, Duntov and his crew were busy working on their solution to the transaxle problem, the stunning XP-882. This one almost made it to the showroom.
lllustrated Corvette Series No. 40 - 1970 XP-882 Corvette Show Car
"Experimental Corvette - Bad Timing
It was a great day for Corvette fans. When the crowds piled into the New York Auto Show on April 2, 1970, they had no idea what Chevrolet was proposing as the next Corvette. The XP-882 Mid-Engine Experimental Corvette had almost everything a Vette lover would want... big-block power, huge wheels and tires, exotic suspension, drop-dead looks, and the engine located in the middle of the car, exactly where an exotic car engine should be.
But we all know how the story ended; they didn't come close to making the car. Forward thinking just couldn't overcome bad timing. Duntov's design team started working out the mechanical challenges for the XP-882 in 1968. Styling penned up a new look that screamed "Corvette!" It was crisp, edgy, modern, yet it "looked" like a Corvette.
New Chevy General Manager John Z. DeLorean stopped work on the XP-882 to pursue making Corvettes based on the new, inexpensive Camaro chassis. DeLorean met with fierce resistance from styling, engineering, and sales to NOT take the car in that direction. So the project was stopped in 1969 and was warehoused until 1970. When Ford announced a similar mid-engine project with DeTomaso, DeLorean resurrected the XP-882 and had it finished for the show car circuit. Because there were no press releases, everyone was stunned. The car magazines were all over it, initiating a feeding frenzy of speculation.
Mid-engine cars were very exotic in the '60s. Not only was the engine midship located, but it was transverse mounted. By using the front-wheel drive, automatic transmission from an Olds Toronado, Duntov was able to quickly get a working prototype. Suspension and brakes were obviously independent and disc. Wheels were spun-aluminum, with vent slots, and tires were E60x15 on the front and G60x15 on the rear. The interior of the car was basic prototype fashion, no frills and no real design at that point. The XP-882 was never officially tested for speed and performance.
Many other Corvette show cars have been more thought out than the XP-882, but the car was rushed into service and not fully developed like show cars of the '60s. But the timing couldn't have been worse for an all-new Corvette. The new platform was going to be expensive to make, requiring new transmission, suspension, body, and interior parts. Actual production wouldn't have started until '72 or '73, just in time for the first Arab oil embargo. Also in the brew was a GM internal push to develop a Wankel-engined prototype, so the second XP-882 chassis was made into the 1973 4-Rotor Aerovette.
All things considered, the XP-882 didn't have a chance, but it sure was exciting. - K. Scott Teeters
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lllustrated Corvette Series No. 51 - 1973 XP-892 Mid-Engine 2-Rotor Experimental Corvette "Rotor-Motor Wankel Corvette?"
The XP-892 just flat-out caught everyone short. It didn't "look" like a Corvette, and used an engine that most of us had never heard of. "What's a Wankel?" Despite its unusual styling, it was a very well done prototype. However, due to the Corvette's sales success, GM was in no hurry to make an all-new car.
GM was hot on the new Wankel rotary engine, and was scheduled to offer the rotor-motor in the Vega for '75. Since 1953, people inside of GM have wanted to make the Corvette something else smaller, bigger, a four-seater, etc. So a Wankel powered prototype was ordered. Actually, two prototypes were made, the XP-892 two-rotor design, shown here, and a four-rotor design using the chassis from the '70, mid-engine, V-8 powered XP-882.
The XP-892 was small, about the same size as a Dino Ferrari or a Datsun 240Z. But when pressed for inside information as to the possibility of this being the next Corvette, the ever cagey Duntov was quoted as saying, "Maybe, but there are no plans to produce it."
The problem was that at 2,600 pounds, with only 180 to 250-hp, performance wouldn't be anywhere close to Corvette standards. Since the Wankel engine had serious heat problems, the XP-892 was more of a study to see if the engine was feasible for a small sports car. Power-to-weight ratio aside, everyone was very pleased with the way the car turned out.
The XP-892 was designed by Chevrolet and built by Pininfarina. Unlike a production Corvette, the XP-892 was a steel, unit-body construction. Duntov referred to the McPherson-strut, independent suspension, and disc brakes as "run of the mill." The 266 cid engine had a single Rochester four-barrel carburetor, and was mated to a modified Hydramatic transmission. Duntov clearly wanted more when he said, "Add three more inches of wheelbase... and maybe a 300-cid engine, and we'd have a good car." As always, he had "something else" up his sleeve, a larger, four-rotor version.
For a prototype, the XP-892 had a very well designed and finished interior. The seats were fixed while the seat backs, steering wheel, and pedals were all adjustable. Between the engine and interior there was a 8.1 cubic foot storage space. The spare tire was under the front hood. It seems that the press never drove the car, as there was never a mention of how the car performed.
GM privately showed the XP-892 and the V-8 powered XP-882 to potential Corvette buyers in '72. The test groups wanted to see something in between. Duntov's opinion was, "When we finally decide what the new Corvette will be, it will be for our own reasons." The man knew what he wanted. - K. Scott Teeters
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lIlustrated Corvette Series No. 52 - 1973 Mid-Engine 4-Rotor Experimental Corvette
"148-MPH Prototype Corvette!"
Zora Arkus-Duntov had that rare blend of a deep understanding of engineering and a passion for speed. Aesthetics did little for Duntov, unless it helped the car's performance. Concerning the Four-Rotor Corvette, Duntov was quoted, "Looking back on my 20-year association with styling, this is the best design ever produced."
From '68 to '73, Chevrolet R&D made five unique mid-engine prototypes. So, what happened? The mid-engine Corvette dream never made it into production because of the Corvette's sales success in the early '70s. Production was at an all-time high in '73, and Chevrolet returned 8,200 orders to dealers because they couldn't make enough cars! So, strictly from a business standpoint, "We're selling all we can make, don't change it!"
Another interesting situation was going on inside of Chevrolet. Four power-players were approaching the end of their careers, and they all wanted a spectacular replacement for the Corvette. Duntov from engineering, Bill Mitchell from styling, Joe Pike from sales, and GM President Ed Cole were powerful Corvette allies. But in business, the bottom line is king.
The 2-Rotor car was nice, but more power was obviously needed. So a bold plan was presented to get the job done. Using the chassis from one of the '70 XP882 cars, two 292.5-cid rotary engines joined together inside a stress member case. The 585-cid "engine" made close to 420hp. The transmission was a Turbo Hydramatic 425 from a Toranado, with a Morse Hy-Vo chain and bevel gears.
Styling was directed by Mitchell and penned out by Henry Haga. Starting with the bumper height datum line, Mitchell's instructions were to "make it sleek." The long tapers on the front and rear, and a steep windshield, made the drag coefficient only 0.325. Gull-wing doors, vents, louvers, scoops, and lots of show car trim made the 4-Rotor Corvette nearly perfect from every angle of view. Slightly longer, lower, and wider than a production '74 Corvette, it looked like "the future."
On a one-mile check track, GM president Ed Cole and Duntov clicked off 148 mph in the 4-rotor Corvette. The car started out with a throaty roar and hit top speed, belching flames and making an ear piercing scream. It was actually faster than a '73 454 Corvette! But not even powerful friends in high places could get this prototype into production. - K. Scott Teeters
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lllustrated Corvette Series No. 53 - 1973 XP-895 All-Aluminum Experimental Corvette
Despite the dark clouds on the automotive horizon in the early '70s, it was a heady time in the Corvette R&D group. The all-aluminum Corvette was the third fully functional prototype to show up in '73.
Before carbon fiber, aluminum was the darling of high-tech automotive development. After all, aluminum was the material of cutting-edge jet aircraft and space craft. An aluminum bodied car wasn't a new idea, since many European exotics had aluminum bodies, as well as Shelby's Cobra. But an aluminum "production" car is another matter.
Like aircraft and space craft, weight was the motivator for this feasibility study. Since the early '60s Detroit had been offering "off-road" aluminum parts intended for NASCAR and drag racing, but these were limited to bumpers, fenders, hoods, doors, and mounting hardware. Mass producing an entire car body would require many assembly and durability considerations. But the prospect of reducing body weight by 40 percent was very appealing.
Using the same chassis and basic body shape of the 2-Rotor Corvette prototype, Reynolds Aluminum used their new 2036-T4 allow to make this all-aluminum Corvette. Except for the bumpers, tires, and interior parts everything else is aluminum. Chevrolet supplied stress analysis and Reynolds sorted out everything else. The main constraint was that the body would have to be spot-welded like a production car. To compensate for aluminum's lower modulus of elasticity, many of the parts and attaching flanges had to be thicker. Two-part epoxy was also used for added strength and to eliminate crevices that would trap salts and dirt.
The Reynolds Aluminum car had minor body differences from the 2-Rotor prototype and used a 400-cid small-block mated to a Hydro-Matic automatic transmission. Side-by-side, the Reynolds car weighed over 400 pounds less than the steel bodied 2-Rotor prototype. But weighed against the Corvette's sales success of the early '70s, GM was in no mood to make an aluminum Corvette. - K. Scott Teeters
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Illustrated Corvette Series No. 72 - 1986 Indy Corvette Concept Car
"Designing the Next Vette"
The lead time needed to design a car can be considerable. Many times, designers start the next generation of a design shortly after a new design is released for production. This was the case with the Corvette Indy concept car. With rave reviews coming in for the new C4 Corvette, it was time to think ahead – way ahead.
In the early '80s, Chevrolet engineers worked on a 2.65-liter Indy car engine with twin intercooled turbos. The engine was never seriously raced, but its development stimulated many of the Corvette team designers. Also, computer chips and electronics were making in-roads in production cars. GM's Design Vice President, Chuck Jordan, wanted these new technologies to be integrated into the design of the next-generation Corvette.
Jordan began with a rendering from staff designer Tom Peters. The design hearkened back to the Italian-like shapes from the Bill Mitchell era. Jordan took the Peters rendering and stuffed as much technology as he could into the sleek new shape.
The "Indy" name was used because the new car would have a 5.7-liter, 32-valve street version of the Indy-car racing engine. Corvette prototypes have had a long history of using mid-engine layouts, and the Corvette Indy was no exception. Other proposed "gee-whiz" features included active suspension, drive-by-wire steering, all-wheel drive, ETAK navigation system, and four-wheel steering.
To take the rendering to the next stage, Jordan commissioned Cecomp of Italy to build a full-size clay model of the Chevrolet III studio design. At this point, the high-tech specifications were just ideas on paper. It was the 3-dimensional, full-size model that would take the design to the next level of a running prototype.
The overall shape of the Corvette Indy was bigger than a production Corvette in every way except the height. The Corvette Indy was 7 inches shorter than a stock Corvette, but 10.4 inches longer and 8 inches wider. The wheelbase was 1.7 inches longer, with the front track 4.5 inches wider and rear track 5.4 inches wider that a stock Corvette. When viewed by it's self, the car looks large. However, when looked at next to a production Corvette, it looks very small due to its low height. The mid-engine drivetrain layout mandates a cab-forward shape. Deep air intakes behind the doors and the inverted rear spoiler are similar to many LeMans-type racers of that time. The upper rear spoiler shape would later be used on the '93 Camaro.
Clay prototypes are usually about 25 percent too much and have to be scaled back. The Corvette Indy successfully impressed GM officials, because by the end of '86 the first of two running Corvette Indy cars was delivered, with the second car being completed in '87. The running prototypes then became the starting point for the 1990 CERV III engineering study. - K. Scott Teeters
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lllustrated Corvette Series No. 76 - 1988 Running Indy Corvette
"The Running Prototype"
After seeing the full-size Corvette Indy clay model, GM brass approved the construction of a running prototype of the bold new design. Clay models are always a little over the top and need to be pulled back, but the running Corvette Indy still sizzled.
The second-stage Corvette Indy was a three part project. The overall design shape and hardware specifications came from the Corvette design team. Since GM had recently purchased Lotus, it was decided to use Lotus' suspension engineering skills to develop a prototype active suspension system. And finally, Cecomp of Italy was contracted to assemble the finished running vehicle. This was to be an interim car while the CERV III engineering study was being built.
Dream cars can be very exciting, but are often not road worthy as production cars. So the original design had to be more realistic. The front end was shortened and the A- and B-pillars were a little more realistic. Also, extra ground clearance and wheel travel in the wheel openings was added. But the shape, flavor, style, and attitude remained.
Running gear was as cutting edge as could be. An early version of the 5.7 LT5 (ZR-1) engine was used. Placement was not only mid-engine (something that Duntov wanted for decades), but was also transverse mounted. The backbone chassis was made of carbon fiber rather than the Kevlar tub of the first version. The Lotus team got to show off their latest active suspension hardware that had just about everything you could imagine. Micro processors and hydraulics replaced the entire standard suspension. The car had full-time four- wheel-drive, four-wheel steering, ABS brakes and traction control. The active suspension allowed for smaller wheel houses, fewer parts, and more interior room.
Weighing only 3,300 pounds and packing 380 hp, the Corvette Indy had enough grunt to carry the Corvette flame. The next stage would be the production-like CERV III. As a prototype, the running Corvette Indy was a success! - K. Scott Teeters
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lllustrated Corvette Series No. 84 1990 CERV III
"Over the Top Design"
The CERV III was a real-world version of the Corvette Indy show car. The Corporate Engineering Research Vehicle III (CERV III) was more than pretty show car; it would be the most advanced Corvette study to date.
Chief of Chevy III Studio, Jerry Palmer, handled the styling details while Dick Balsey was the engineer on the project. The objective was to showcase the Chevrolet design team and Lotus' advanced racing experience. This was no easy task, by any means.
The nose of the Indy had to be shortened and the side windows flattened out so that they could go down into the doors. The wheel openings had to be opened up to allow 3.5 inches of travel and the rocker panels reshaped to accommodate side-mounted fuel cells. Also, the overall height had to be increased a few inches.
The CERV III's hardware was just as exciting as the body shape. To start, the LT5 engine was treated to two Garrett T3 turbochargers that bumped the horsepower up to 650 and the torque to 655 lb-ft. The 3,400-pound CERV III ran 0 to 60 in 3.9 seconds, had a top speed of 225 mph, and had 1.1 gs of lateral acceleration!
Since the car was completely built by Lotus in England, carbon fiber was used everywhere possible, just like a race car. The underbody was carbon fiber with a fiberglass-finish coating. The classic Lotus backbone chassis was made of carbon fiber and weighed only 38 pounds.
Although the suspension looked normal, the springs and A-arms were made of titanium. Actuators were used in place of shock absorbers and were connected to a state-of-the-art computer-controlled active suspension system. ABS braking and traction control was also part of the package. The transverse-mounted engine used a six-speed automatic transmission for all-wheel-drive and four-wheel steering.
The completed car was more than anyone expected, especially the bean counters. Cost estimates put the price tag between $300,000 and $400,000, making the world-class CERV III the most expensive proposed Corvette ever! - K. Scott Teeters