C4

:For an outline of all the Chevrolet Corvette generations see 
The C4 generation was introduced at the close of 1982 production as a 1984 model and ended in 1996. This means that there are no 1983 model year Corvettes (though 44 prototype or pre-production 1983s were built, of which #23 survives today and is housed at the National Corvette Museum in Bowling Green). It is the fourth generation of Corvettes built and marketed by the Chevrolet division of American automaker General Motors.
The C4 Corvette is known for its sleek look. Instead of fiberglass, it was made from reaction injected molding plastics, a sheet molding compound. The C4 coupe also is the first Corvette to have a glass hatchback (except for the 1982 Collector Edition) for better storage access. It also had all new brakes with aluminum calipers. The Corvette C4 came standard with an electronic dashboard with digital liquid crystal displays for speed and RPM. The C4 was a complete redesign of the previous generation, and the emphasis was on handling. This handling came at the cost of a solid, uncompromising ride, especially with the Z51 performance handling package. The unit-body frame used in the C4 was prone to rattles and squeaks due to minimal sound deadening. Also due to the external unit-body frame, the door sills were quite deep and entry and exit have been likened to a "fall in and climb out" experience. The emergency brake, located between the door sill and the drivers seat, was moved lower and toward the rear of the car in 1988 for easier entry and exit.
From 1984 through 1988, the Corvette was available with a Doug Nash "4+3" transmission - a 4-speed manual coupled to an automatic overdrive on the top three gears. This unusual transmission was a synergy that allowed corvette to keep a stout 4 speed, but add an overdrive. As technology progressed, it was replaced by a modern ZF 6-speed manual. However, the C4 performance was hampered by its L98 engine until 1992, when the second-generation LT1 was installed, markedly improving the C4s performance. 1996 was a high point of small block Chevrolet development and the LT4 was installed in all manual transmission cars. 
The 1986 Corvette is notable for being the first car with an electronic anti-theft system. GM had created the Pass Key I, where each key contained a special pellet that could be detected and identified by the car's computer system by detecting electrical resistance. Being early in the rollout of this new technology, there were only 15 different resistance values available.
==B2K Callaway Twin-Turbo==
In 1987, the factory B2K option appeared at dealers. The option's price was almost equal to the base price of the Corvette.
The Callaway Corvette was a Regular Production Option (RPO) B2K, the only time in Chevrolet's history a specialist manufacturer was entrusted with a technically advanced high performance RPO. The B2K option was critical in bringing a select few Corvettes to a higher performance level. Although often compared with Chevrolet's ZR-1 option, they were simply two different approaches to solving the issue of bringing a higher performance Corvette to market. The early B2K's produced and of torque. [4] The later B2K's produced and of torque. [5]
A derivative of the Twin Turbo Corvette, the Callaway SledgeHammer, recorded a speed of on Ohio's Transportation Research Center track, although it did not achieve this speed in street-legal trim.
==ZR-1==
During 1986, General Motors acquired Group Lotus, the UK based engineering consulting and performance car manufacturing firm. The Corvette division approached Lotus with the idea of developing the world's fastest production car, to be based on the C4 generation Corvette. With input from GM, Lotus designed a new engine to fit in place of the L98 V8 that was powering the standard C4. The result was what GM dubbed the LT5, an aluminum-block V-8 with the same bore centers as the L98, but with four overhead camshafts, 32 valves. Lotus also designed a unique air management system for the engine to provide a wider power band by shutting off 8 of the 16 intake runners and fuel injectors when the engine was at part-throttle, while still giving the ZR-1 a stellar when at wide open throttle.
In addition to the engine, Lotus helped GM design the ZR-1's upgraded braking and steering systems, and helped them pick the settings for the standard "FX3" adjustable active ride control that Chevrolet was fitting to the car, helping to ensure that the vehicle was more than just a modern-day muscle car with a big engine and no real capability on the track.
GM found that the engine required special assembly, and that neither the Corvette plant in Bowling Green, Kentucky nor any of their normal production facilities could handle the workload, so Mercury Marine corporation of Oklahoma was contracted to assemble the engines and ship them to the Corvette factory in Bowling Green where the ZR-1s were being assembled. 
The vehicle went on sale in 1990 and was available only as a coupe. It was distinguishable from other Corvette coupes by its wider tail section, 11" wide rear wheels and its new convex rear fascia with four square shaped taillights and a CHMSL (center high mounted stop lamp) attached to the top of the hatch glass instead of between the taillights.
The ZR-1 displayed stunning ability both in terms of acceleration and handling capabilities, but carried with it an astonishingly high price. MSRP for the ZR-1 in 1990 was $58,995, almost twice the cost of a non-ZR-1, and had ballooned to $66,278 by 1995; it has been rumored that some dealers successfully marked units as high as $100,000. Even at base MSRP, this meant that the ZR-1 was competing in the same price bracket as cars like the Porsche 964, making it a hard sell for GM dealers.
In 1991, the ZR-1 and base model received updates to body work, interior, and wheels. The rear convex fascia that set the 1990 ZR-1 apart from the base model found its way to all models, making the high-priced ZR-1 even less distinguishable. Further changes were made in 1992, including extra ZR-1 badges on the fenders and making traction control a standard feature, and in 1993, when Lotus designed modifications were made to the cylinder heads, exhaust system and valvetrain of the LT5, bringing horsepower up to 405. In addition, a new exhaust gas recirculation system improved emissions control. The model remained nearly unchanged into the 1995 model year, after which the ZR-1 was discontinued as the result of waning interest and the fact that Chevrolet had never been able to sell them easily. A total of 6,939 ZR-1s were manufactured over the six year period.
Not until the debut of the C5 platform Z06 would Chevrolet have another production Corvette capable of matching the ZR-1's performance.
Although the ZR-1 was extremely quick (0-60 mph in 4.6 seconds, and onto 180+ mph), the huge performance of the LT5 engine was matched by its robustness. As evidence of this, a stock ZR-1 set a number of international and world records at a test track in Fort Stockton, Texas on March 1, 1990, verified by the FIA (Fédération Internationale de l'Automobile), including seven new international records:
* at 
* at 
* at 
* }} at (World Record)
* at (World Record)
* 12 Hours Endurance at 
* 24 Hours Endurance at for miles (World Record)
==ZR2 (1989)==
Also called 'Big Doggie', it is a concept model build based on C4 Corvette, but with LS-6 engine block, 6-speed manual transmission1989 Chevrolet Corvette ZR2 Roadster, and includes electronic fuel injection.C4 Corvette Performance Rebuild - Why Ask Y?
The vehicle was built by Corvette Development Engineering as a development car to study the possibility of achieving ZR-1 performance while reducing cost using big block engine. The engine was rated 400hp.Re: TECH: GM Heritage Collection Sales at Barrett-Jackson
The prototype vehicle was sold in 2009 Barrett-Jackson Scottsdale auction for winning bid price of $65,000.1989 Corvette ZR-2 Sells at 2009 Barrett-Jackson
==CERV III==
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In June 1985, Chevrolet Chief Engineer Don Runkle and Lotus' Tony Rudd discuss creating a new show car to show off their engineering expertise. The project would become the CERV III (Corporate Engineering Research Vehicle III). It was first unveiled in Detroit Automobile Show in January 1986 as Corvette Indy prototype car.
==Corvette GTP==
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As part of GM's initiative to promote the new C4 Corvette, they funded a program in the IMSA GT Championship to run a GTP-class prototype under the Corvette name, mostly run by Hendrick Motorsports. Although the Corvette GTP actually shared very little with the C4 Corvette, including the lack of a V8 engine in some races, it did use some styling cues. The project lasted until 1988 with mixed success.
==Special Editions==
=== Pace Car Convertible ===
A yellow convertible was the pace car for the 1986 Indianapolis 500. This marked the return of the convertible body style, absent from the Corvette lineup since 1975. All 7,315 1986 convertible Corvettes had special Pace Car Replica decals.
=== 35th Anniversary ===
The 1988 35th Anniversary edition was a white coupe with a black top. 2,050 were built.
=== 40th Anniversary ===
The 1993 40th Anniversary package was available on all models. It included Ruby Red metallic paint and Ruby Red leather sport seats, along with special trim and emblems. 6,749 were sold at an additional cost of $1,455.
=== Indy Pace Car ===
In 1995 a C4 convertible was again the pace car for the Indianapolis 500, and a special pace car edition was offered. 527 were built.
=== Grand Sport ===
Chevrolet released the Grand Sport (GS) version in 1996 to mark the end of production of the C4 Corvette. The Grand Sport moniker is a nod to the original Grand Sport model produced in 1963. A total of 1,000 GS Corvettes were produced, 810 as coupes and 190 as convertibles. The 1996 GS came with the high-performance LT4 V8 engine, producing and of torque. The Grand Sport came only in Admiral Blue with a white stripe down the middle, and black wheels and two red stripes on the front left wheel arch added to its distinctive look.
=== Collector Edition ===
The 1996 Collector Edition was the last of the C4 Corvettes, just as the 1982 Collector Edition was the last of the C3s. It included Sebring Silver paint and special trim. Of the 5,412 built, 4,031 were coupes and 1,381 were convertibles. It cost $1,250 extra.
==Production notes==
Year 	Production	Base Price	Notes
1984 	51,547 	$21,800 	C4 hatchback body is popular. Digital instrumentation is controversial. L83 engine continued from 1982
1985 	39,729 	$24,891 	More powerful L98 engine introduced.
1986 	35,109 	$27,027 	First convertible since 1975. Third brake light, antilock brakes, and key-code anti-theft system are new
1987 	36,632 	$27,999 	Callaway twin-turbo offered through dealers with GM warranty.
1988 	22,789 	$29,480 	New wheel design. 35th Anniversary special edition.
1989 	26,412 	$32,045 	ZF 6-speed manual replaces Doug Nash 4+3.
1990 	23,646 	$32,479 	ZR-1 is introduced with DOHC LT5 engine. Interior redesigned to incorporate drivers-side air bag.
1991 	20,639 	$33,005 	Restyled exterior. Last year for the Callaway B2K twin turbo.
1992 	20,479 	$33,635 	New LT1 engine replaces the L98. Traction control is standard.
1993 	21,590 	$34,595 	Passive keyless entry is standard. 40th Anniversary special edition.
1994 	23,330 	$36,185 	New interior including passenger airbag.
1995 	20,742 	$36,785 	Last year of the ZR-1. Minor exterior restyling. Indy Pace Car special edition.
1996 	21,536 	$37,225 	Optional LT4 engine with . Collectors Edition and Grand Sport special editions. First year with OBD II diagnostic capability.
Total	366,227 	 	
==Engines==
right|thumb|250px| LT5 V8 in a C4 ZR-1
Engine	Year 	Power	Torque
L83 V8	1984 	 	
L98 V8	1985–1986 	 	
L98 V8	1987–1989 	 	
L98 V8	1987 (B2K Callaway) 	 	
L98 V8	1988–1989 (coupes with 3.07 rear)	 	
L98 V8	1988-1989 (B2K Callaway) 	 	
L98 V8	1990-1991 	 	
L98 V8	1990-1991 (coupes with 3.07 rear)	 	
L98 V8	1990-1991 (B2K Callaway) 	 	
LT5 V8	1990–1992 	 	
LT5 V8	1993–1995 	 	
LT1 V8	1992–1993 	 	
LT1 V8	1994–1995 	 	
LT1 V8	1996 	 	
LT4 V8	1996 	 	
==Further reading==
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