Mid Engined Vettes .....
Discussion
vetteheadracer said:
One of the prototypes (the Twin Rotor I think) was at GFOS last year. It is owned by Tom Falconer owner of Claremont Corvettes in Kent.
That was XP-897 a small machine about the same size as a Dino Ferrari or a Datsun 240Z. Built by Pininfarina to a GM design, the XP-897GT "Two-Rotor Car" appeared in 1973 as a showcase for GM's then-imminent Wankel-type rotary engine. Like the original XP-882, it was widely believed to be a precursor of the next generation Corvette.
In 1970, Chevrolet obtained a licence for the Wankel RCE from NSU, for a cost of $50 million, at the direction of GM President Ed Cole, whose background was engineering. They began building a two-rotor and a four-rotor Corvette, in the highly desirable mid-engine format. Zora Arkus-Duntov met with Bill Mitchell to discuss a four rotor Corvette in 1970. Zora gave him the chassis from the XP-895 mid-engine experimental car shown at the April 1970 New York Auto show. A fibreglass model was approved in June 1971 by Cole.
On Jan. 14, 1972, a chassis was shipped to Pininfarina, Turin, Italy so that the body could be constructed by the famed design studio. In June of the same year, a 2 rotor Corvette with a steel body was viewed by GM management. The same year DeLorean at GM commissioned a two-rotor version of the XP-882 and built it as the XP-987GT.
In January 1973, a Corvette body, also based on the XP-882 chassis, was built for an experimental four-rotor car. This was designed by Charles M. Jordan and William L. Mitchell's staff. It got the project name XP-895. A second version of this body was made in aluminum alloy and got a 454 V-8. Two of the two rotor Wankels were glued together into a four rotor 420 bhp engine and this was installed in the first XP-895 by Gib Hufstader. Mitchell's staff under Henry Haga, at Duntov's urging, designed an all-new body for the "Four-Rotor Car".
By April, the GALCIT wind tunnel in California was used to test the aerodynamic qualities of the 4-rotor Corvette. The coefficient of drag came out very low for its time: 0.325. The car was only 44 inches high and had gull-wing doors. The interior had digital instruments.
In September 13, 1973 a 266 ci two-rotor Corvette (XP-897GT) was shown in Frankfurt, Germany with a steel body. The four-rotor 390 ci mid-engined Corvette was shown at Paris, France on Oct. 4, 1973, as well as the two-rotor. Oct. 17 they are both shown at the London Auto Show.
On September 24, 1974, GM Pres. Ed Cole postponed the introduction of the Wankel engine, ostensibly due to emissions difficulties. He retired the same month. In 1976 the body was resuscitated with a V-8 400 engine and redubbed the "Aerovette". On April 12, 1977, GM announced it is stopping all R & D on rotary engines.
The 74 Chevy Vega was originally planned for a rotary engine. This was delayed to a later plan for 1975, but was dropped in 1974. The engine was a two rotor water cooled with oil cooling of the rotors. There was a single spark plug per rotor. The housings were all iron. It is also reported that a 206 cid 2 rotor engine was intended for the 75 Monza 2+2.
A GM rotary was going to be used for the American Motors Pacer. The compact size of the engine allowed a flattened hood and radical styling.
>> Edited by The Wiz on Thursday 22 April 11:12
You are truly "The Wiz"!
Funny when you read the old write ups (like in teh "Brooklands" compilations and GM and writers alike are going on about what they think the "future" for the Corvette will be.
Then they just carried on watering down the poor old C3, admittedly mainly due to government legislation but it's a bit sad that they couldn't have at least kept it "looking" like a 68-72.
Maybe that's what the C7 should look like...?
Funny when you read the old write ups (like in teh "Brooklands" compilations and GM and writers alike are going on about what they think the "future" for the Corvette will be.
Then they just carried on watering down the poor old C3, admittedly mainly due to government legislation but it's a bit sad that they couldn't have at least kept it "looking" like a 68-72.
Maybe that's what the C7 should look like...?
That's really interesting, isn't it? I wonder if they also had rebuild issues like Mazda had with the earlier RX-7's.
The Wankel engine is an interesting idea, but the downfalls always seem to be the same - heavy fuel use, bad emissions and difficulty to maintain.
Even the RX-8, which kicks out an unfeasible amount of power for the size of the engine (1.3Litre and about 230 bhp) isn't that good on fuel.
I'll just stick with my 5.7 litre monster!
The Wankel engine is an interesting idea, but the downfalls always seem to be the same - heavy fuel use, bad emissions and difficulty to maintain.
Even the RX-8, which kicks out an unfeasible amount of power for the size of the engine (1.3Litre and about 230 bhp) isn't that good on fuel.
I'll just stick with my 5.7 litre monster!
The C4 was almost a mid-engine Corvette!
For one brief shining moment, General Motors honestly intended to build a mid-engine Corvette for public sale. The moment came in late 1977, just as "America's only true sports car" was about to celebrate its 25th anniversary.
Regrettably, the decade-old "Shark" model had to carry the birthday banner, because the midships 'Vette wasn't slated until 1980. But enthusiasts wouldn't have minded the wait, for the car in question was a virtual clone of the stunning Aerovette, perhaps the most widely admired of the many mid-engine experiments with which GM had been teasing Corvette lovers since the late Fifties. Those tantalizing exercises were owed to Zora Arkus- Duntov, fabled as chief Corvette engineer almost since the car's 1953 inception. After conjuring the open-wheel CERV I singleseater and envelope-bodied CERV II (the letters stood for Corvette Engineering Research Vehicle), Duntov turned to more passenger-oriented designs, beginning with the Astro II of 1968. Like the previous year's Corvair-based Astro I, this was a curvy, groundsniffing two-seat coupe with a lift-up rear engine cover/cockpit canopy. It was also a remnant of project XP-880, a mid-engine effort that Duntov hoped would appear in showrooms for 1968. But GM decided to stick with traditional front-engine design and a little-changed 1963-67 Sting Ray chassis for that year's new "Shark" generation, thus rendering Astro II a dead end.
Undaunted, Duntov quickly turned to what would be the genesis of the Aerovette, project XP-882. Because his previous mid-engine proposals carried Chevy V-8s in longitudinal fashion, they required a costly, purpose-designed transaxle that not even vast Chevrolet could justify for a low-volume sports car. Here, Duntov tackled the problem by turning the engine 90 degrees and putting a stock GM Turbo Hydra-matic "end on" to it. The transmission was driven by chain from the crankshaft, and connected to a stock Corvette differential via a short driveshaft turning a right-angle at the front. Because the driveshaft had to pass through the sump, it was encased in a tube. If not an elegant solution, it was at least affordable.
Duntov's engineers built two XP-882s during 1969, an identical pair of swoopy fastbacks with an unfortunately blunt front but a dramatic louvered boattail, as on the experimental Mako Shark II of four years before. Yet almost on the day they were finished, John Z. DeLorean became Chevy general manager and canceled the program as impractical and costly. His decision stood only a year. When Ford announced plans to sell the Italian-built mid- engine DeTomaso Pantera through Lincoln-Mercury dealers, DeLorean ordered one XP-882 cleaned up for display at the 1970 New York Auto Show. But though car magazines were quick to proclaim that the mid-engine Corvette had finally arrived, GM never said anything about production.
Meantime, GM was working feverishly on its own rendition of the rotary-piston engine devised by Dr. Felix Wankel at Germany's NSU, having secured a manufacturing agreement at the behest of president Ed Cole, the legendary Chevy engineer who had lately become an ardent rotary advocate. Along with a Wankel-powered version of Chevy's small Vega, which would never materialize, Cole ordered up a sports car designed around the developing two-rotor GMRCE (General Motors Rotary Combustion Engine) then being eyed for production. Coded XP- 897GT, this handsome little coupe had GM styling, but was built by the famed Pininfarina works in Italy. When displayed during 1973 with the prosaic title "Two-Rotor Car," "buff books" again hailed the advent of the mid-engine Corvette.
The previous year, DeLorean had authorized further work on the XP-882 chassis, as well as a new body from the corporate Design Staff under William L. Mitchell. Sufficiently changed to warrant a new project code, XP-895, this ended up looking a bit like the Two-Rotor from the sides, but carried a deeply inset "sugar scoop" rear window instead of flush glass. By early '72, a chance discussion with officials at Reynolds Metals Company prompted construction of a near-identical body in aluminum alloy, and in which form the XP-895 became the "Reynolds Aluminum Car." It, too, garnered lots of ink as the presumed next Corvette -- and because its big-block 454 V-8 promised super performance against a svelte curb weight of around 3000 pounds. As if all this weren't enough, the remaining XP-882 chassis was stripped of its V-8 and given a pair of Vega Wankels bolted together into a four-rotor, 420-bhp super-rotary. To make sure no ." one missed the change, Duntov persuaded Mitchell and staff to design yet another all-new body for what was called... the "Four- Rotor Car."
Exceptional aerodynamics was its overriding design goal. At just 44 inches high, the Four-Rotor tested out with a drag coefficient of only 0.325 -- better than many production cars of 20 years later. But its real triumphs were sumptuous sensuality and remarkable symmetry. Unlike most midships designs, the Four- Rotor gave no clue as to the location of its engine; indeed, its styling would have suited a front-engine layout just as well. And where most "aero" bodies had definite edges, this one cleverly disguised them. The result was organic, "all-of-a-piece," and nearly timeless -- a triumph of surface over line.
Jerry Palmer, who would shape the 4th-generation 1984 Corvette, was among the designers who worked on the Four- Rotor car, which was first shown in late 1973. Car and Driver magazine thought it "the betting man's choice to replace the Stingray." But that winter brought the world's first energy crisis, which exposed the Wankel as a relative gas guzzler. With that, GM scrapped its rotary work and all plans for Wankel-powered cars.
Three years later, the Four-Rotor was still under a sheet in GM's Special Vehicles warehouse. Like DeLorean (who left GM in a huff during 1972), Mitchell had the car dragged out, this time to replace the double-Wankel with a Chevy 400 V-8. After changing the I.D. to "Aerovette," Mitchell lobbied for the car as the next Corvette. He usually got what he wanted, and GM chairman Thomas Murphy actually approved the Aerovette for 1980 production. Ironically, he might have been at least partly swayed by the imminent threat from the rear-engine DMC-12, the now-infamous sports-car effort of none other than John Z. DeLorean.
The process to productionize the Aerovette moved swiftly. A full-scale clay was ready by late '77, and tooling orders were about to be placed. The showroom model would have had a steel frame with Duntov's clever transverse driveline and probably a 350 V-8, which was then Corvette's mainstay engine. Transmissions would have likely been the usual four-speed manual and three- speed Turbo Hydra-Matic, and suspension would have come off the old "Shark" per Duntov's original cost-cutting aim. So despite its complex gullwing doors, the Aerovette wouldn't have cost a whole lot more to build than a front-engine 'Vette. Indeed, 1980 retail price was projected in the $15,000-$18,000 range. Best of all, the gorgeous styling would have survived completely intact. As Mitchell later confirmed: "The only difference between the Aerovette and its production derivation was an inch more headroom. Otherwise it was the same."
But once more, the mid-engine Corvette was not to be. There were several reasons. First, the project lost its two biggest boosters when Duntov retired in 1974 and Mitchell followed suit three years later. Ed Cole was gone by then, too. A further blow came from Duntov's successor, David R. McLellan, who preferred the front/mid-engine concept over a rear/mid layout for reasons of packaging, manufacturing economy, even on-road performance. But the deciding factor was sales -- or rather the likely lack of same. Though Porsche, Fiat, and other import makes had all preffered mid-engine sports cars for several years, none had sold very well in the U.S. Datsun, meantime, couldn't build enough of its admittedly cheaper front-engine 240Z -- as GM bean-counters evidently observed. Simply put, the mid-engine was risky.
It bears mentioning that GM explored one other avenue at the same time as the production Aerovette. This was a midship V-6 Corvette with running gear taken from the planned new 1980 X- body compacts. It was the same idea later applied to Pontiac's Fiero: a transverse front-drive powertrain plunked behind a two- seat cockpit to drive the rear wheels. The concept was hardly new, of course. Porsche, Lotus, and Fiat had all used high-volume, off- the-shelf components to create roadgoing middies -- the "corporate kit car" formula that promised similar cost savings here. The contemplated engine was the now-familiar 60-degree 2.8-liter V-6 then in the works at Chevrolet. Styling was created by the Chevy Three Production Studio under Jerry Palmer, which sculpted clean, somewhat angular lines with Aerovette overtones.
But the mid/V-6 was doomed by the same factors that killed the Aerovette. It had other drawbacks, too. As Car and Driver later recounted: "A new front-engine/rear-drive Camaro had just been approved with [350-cid] V-8 capacity; there was no way a V-6 Corvette could continue as the flagship of the Chevy fleet without turbocharging and intercooling (GM did dally with a turbocharged Vette in 1979 featuring a L82, 350 ci engine, AiResearch turbo charger and a modified Cadillac fuel injection system), and it would be tough to sell such a costly, high-tech alternative to management. At the same time, the corporation had yet to develop a transaxle that could withstand the torque such an engine would produce. In addition, GM had big plans for widespread use of its X-car components in future high-volume cars... limiting the availability of parts [for Corvette]." Exit mid/V-6.
With that, work toward a new front-engine design got underway in earnest during 1978. The result appeared five years later, in time for Corvette's 30th birthday. Mitchell later compared its styling to a "grouper." Tellingly, this 4th-generation 'Vette has yet to equal the sales performance of the old "Shark," encouraging hopeful types to anticipate yet another fling with mid-engine design. But those hopes were dashed by GM's 1993 announcement that the next-generation Corvette would continue the familiar front-engine rear-drive configuration.
>> Edited by The Wiz on Thursday 22 April 11:17
For one brief shining moment, General Motors honestly intended to build a mid-engine Corvette for public sale. The moment came in late 1977, just as "America's only true sports car" was about to celebrate its 25th anniversary.
Regrettably, the decade-old "Shark" model had to carry the birthday banner, because the midships 'Vette wasn't slated until 1980. But enthusiasts wouldn't have minded the wait, for the car in question was a virtual clone of the stunning Aerovette, perhaps the most widely admired of the many mid-engine experiments with which GM had been teasing Corvette lovers since the late Fifties. Those tantalizing exercises were owed to Zora Arkus- Duntov, fabled as chief Corvette engineer almost since the car's 1953 inception. After conjuring the open-wheel CERV I singleseater and envelope-bodied CERV II (the letters stood for Corvette Engineering Research Vehicle), Duntov turned to more passenger-oriented designs, beginning with the Astro II of 1968. Like the previous year's Corvair-based Astro I, this was a curvy, groundsniffing two-seat coupe with a lift-up rear engine cover/cockpit canopy. It was also a remnant of project XP-880, a mid-engine effort that Duntov hoped would appear in showrooms for 1968. But GM decided to stick with traditional front-engine design and a little-changed 1963-67 Sting Ray chassis for that year's new "Shark" generation, thus rendering Astro II a dead end.
Undaunted, Duntov quickly turned to what would be the genesis of the Aerovette, project XP-882. Because his previous mid-engine proposals carried Chevy V-8s in longitudinal fashion, they required a costly, purpose-designed transaxle that not even vast Chevrolet could justify for a low-volume sports car. Here, Duntov tackled the problem by turning the engine 90 degrees and putting a stock GM Turbo Hydra-matic "end on" to it. The transmission was driven by chain from the crankshaft, and connected to a stock Corvette differential via a short driveshaft turning a right-angle at the front. Because the driveshaft had to pass through the sump, it was encased in a tube. If not an elegant solution, it was at least affordable.
Duntov's engineers built two XP-882s during 1969, an identical pair of swoopy fastbacks with an unfortunately blunt front but a dramatic louvered boattail, as on the experimental Mako Shark II of four years before. Yet almost on the day they were finished, John Z. DeLorean became Chevy general manager and canceled the program as impractical and costly. His decision stood only a year. When Ford announced plans to sell the Italian-built mid- engine DeTomaso Pantera through Lincoln-Mercury dealers, DeLorean ordered one XP-882 cleaned up for display at the 1970 New York Auto Show. But though car magazines were quick to proclaim that the mid-engine Corvette had finally arrived, GM never said anything about production.
Meantime, GM was working feverishly on its own rendition of the rotary-piston engine devised by Dr. Felix Wankel at Germany's NSU, having secured a manufacturing agreement at the behest of president Ed Cole, the legendary Chevy engineer who had lately become an ardent rotary advocate. Along with a Wankel-powered version of Chevy's small Vega, which would never materialize, Cole ordered up a sports car designed around the developing two-rotor GMRCE (General Motors Rotary Combustion Engine) then being eyed for production. Coded XP- 897GT, this handsome little coupe had GM styling, but was built by the famed Pininfarina works in Italy. When displayed during 1973 with the prosaic title "Two-Rotor Car," "buff books" again hailed the advent of the mid-engine Corvette.
The previous year, DeLorean had authorized further work on the XP-882 chassis, as well as a new body from the corporate Design Staff under William L. Mitchell. Sufficiently changed to warrant a new project code, XP-895, this ended up looking a bit like the Two-Rotor from the sides, but carried a deeply inset "sugar scoop" rear window instead of flush glass. By early '72, a chance discussion with officials at Reynolds Metals Company prompted construction of a near-identical body in aluminum alloy, and in which form the XP-895 became the "Reynolds Aluminum Car." It, too, garnered lots of ink as the presumed next Corvette -- and because its big-block 454 V-8 promised super performance against a svelte curb weight of around 3000 pounds. As if all this weren't enough, the remaining XP-882 chassis was stripped of its V-8 and given a pair of Vega Wankels bolted together into a four-rotor, 420-bhp super-rotary. To make sure no ." one missed the change, Duntov persuaded Mitchell and staff to design yet another all-new body for what was called... the "Four- Rotor Car."
Exceptional aerodynamics was its overriding design goal. At just 44 inches high, the Four-Rotor tested out with a drag coefficient of only 0.325 -- better than many production cars of 20 years later. But its real triumphs were sumptuous sensuality and remarkable symmetry. Unlike most midships designs, the Four- Rotor gave no clue as to the location of its engine; indeed, its styling would have suited a front-engine layout just as well. And where most "aero" bodies had definite edges, this one cleverly disguised them. The result was organic, "all-of-a-piece," and nearly timeless -- a triumph of surface over line.
Jerry Palmer, who would shape the 4th-generation 1984 Corvette, was among the designers who worked on the Four- Rotor car, which was first shown in late 1973. Car and Driver magazine thought it "the betting man's choice to replace the Stingray." But that winter brought the world's first energy crisis, which exposed the Wankel as a relative gas guzzler. With that, GM scrapped its rotary work and all plans for Wankel-powered cars.
Three years later, the Four-Rotor was still under a sheet in GM's Special Vehicles warehouse. Like DeLorean (who left GM in a huff during 1972), Mitchell had the car dragged out, this time to replace the double-Wankel with a Chevy 400 V-8. After changing the I.D. to "Aerovette," Mitchell lobbied for the car as the next Corvette. He usually got what he wanted, and GM chairman Thomas Murphy actually approved the Aerovette for 1980 production. Ironically, he might have been at least partly swayed by the imminent threat from the rear-engine DMC-12, the now-infamous sports-car effort of none other than John Z. DeLorean.
The process to productionize the Aerovette moved swiftly. A full-scale clay was ready by late '77, and tooling orders were about to be placed. The showroom model would have had a steel frame with Duntov's clever transverse driveline and probably a 350 V-8, which was then Corvette's mainstay engine. Transmissions would have likely been the usual four-speed manual and three- speed Turbo Hydra-Matic, and suspension would have come off the old "Shark" per Duntov's original cost-cutting aim. So despite its complex gullwing doors, the Aerovette wouldn't have cost a whole lot more to build than a front-engine 'Vette. Indeed, 1980 retail price was projected in the $15,000-$18,000 range. Best of all, the gorgeous styling would have survived completely intact. As Mitchell later confirmed: "The only difference between the Aerovette and its production derivation was an inch more headroom. Otherwise it was the same."
But once more, the mid-engine Corvette was not to be. There were several reasons. First, the project lost its two biggest boosters when Duntov retired in 1974 and Mitchell followed suit three years later. Ed Cole was gone by then, too. A further blow came from Duntov's successor, David R. McLellan, who preferred the front/mid-engine concept over a rear/mid layout for reasons of packaging, manufacturing economy, even on-road performance. But the deciding factor was sales -- or rather the likely lack of same. Though Porsche, Fiat, and other import makes had all preffered mid-engine sports cars for several years, none had sold very well in the U.S. Datsun, meantime, couldn't build enough of its admittedly cheaper front-engine 240Z -- as GM bean-counters evidently observed. Simply put, the mid-engine was risky.
It bears mentioning that GM explored one other avenue at the same time as the production Aerovette. This was a midship V-6 Corvette with running gear taken from the planned new 1980 X- body compacts. It was the same idea later applied to Pontiac's Fiero: a transverse front-drive powertrain plunked behind a two- seat cockpit to drive the rear wheels. The concept was hardly new, of course. Porsche, Lotus, and Fiat had all used high-volume, off- the-shelf components to create roadgoing middies -- the "corporate kit car" formula that promised similar cost savings here. The contemplated engine was the now-familiar 60-degree 2.8-liter V-6 then in the works at Chevrolet. Styling was created by the Chevy Three Production Studio under Jerry Palmer, which sculpted clean, somewhat angular lines with Aerovette overtones.
But the mid/V-6 was doomed by the same factors that killed the Aerovette. It had other drawbacks, too. As Car and Driver later recounted: "A new front-engine/rear-drive Camaro had just been approved with [350-cid] V-8 capacity; there was no way a V-6 Corvette could continue as the flagship of the Chevy fleet without turbocharging and intercooling (GM did dally with a turbocharged Vette in 1979 featuring a L82, 350 ci engine, AiResearch turbo charger and a modified Cadillac fuel injection system), and it would be tough to sell such a costly, high-tech alternative to management. At the same time, the corporation had yet to develop a transaxle that could withstand the torque such an engine would produce. In addition, GM had big plans for widespread use of its X-car components in future high-volume cars... limiting the availability of parts [for Corvette]." Exit mid/V-6.
With that, work toward a new front-engine design got underway in earnest during 1978. The result appeared five years later, in time for Corvette's 30th birthday. Mitchell later compared its styling to a "grouper." Tellingly, this 4th-generation 'Vette has yet to equal the sales performance of the old "Shark," encouraging hopeful types to anticipate yet another fling with mid-engine design. But those hopes were dashed by GM's 1993 announcement that the next-generation Corvette would continue the familiar front-engine rear-drive configuration.
>> Edited by The Wiz on Thursday 22 April 11:17
A 1958 Corvette and was modified to be the personal car of William L. "Bill" Mitchell. First, in 1958, it received a special rear end of duck-tail type, which was incorporated in the regular '61 Corvette, and the front end was redesigned to look almost like the one of the Oldsmobile F88 '54 show car. In 1959, the car was modified again to became a real show car (pictured): longer rear end, new front end with smaller air intake, new transparent roof with a periscope in the middle of the two bubbles. 
1973 XP-882, Arguably more stunning than the Two- Rotor XP-897GT was the so-called "Four-Rotor Car" that appeared a bit later in 1973. Built on the first XP-882 chassis under the aegis of company design chief Bill Mitchell, it carried a pair of GM's experimental two-rotor engines bolted together into a 420 horsepower "super Wankel." A Corvette-like face and obvious high performance potential were taken as strong suggestions that GM was brewing a radical new Corvette for the late Seventies or early Eighties. 
The CERV III made it's debut at the Detroit International Auto Show. The car's mid-engine V8 is a 5.7 liter 32 valve, dual overhead cam LT5 Engine with the addition of twin turbos and internal modifications. Speed 225 MPH , horsepower is rated at 650. In the De Lorean program this evening there was a shot of the lovely Jon Zachary DeL sitting on the hood of a blue Stingray back in his GM days. Maybe they wouldn't let him put the engine in the back so he left to do his own thing in Northern Ireland. Least ways the engine stayed at the right end of the vette.
The CERV III should have been built, It was the next logical step after the ZR1. I've always liked it and after seeing it at Nashville I like it even more.
But no GM did a u-turn and turned their back on the over head cams.
Maybe after driving an LT5 I am biased but surely that was a few steps backwards.
But no GM did a u-turn and turned their back on the over head cams.
Maybe after driving an LT5 I am biased but surely that was a few steps backwards.
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