Dave McClellan was a good Corvette chief engineer who did a great job at a difficult time in automotive history. He had the good fortune of working alongside of Chief Zora, but had the bad fortune of following Corvette's most GENIUS Cheif engineer. This resulted in some unearned unfavorable comparisons while Dave was at the helm. Remember, Zora had driven and won at Lemans and McClellan was NOT race driver. But he WAS a very good engineer who had learned from the best. McClellan's team put together a better handling, more powerful new generation that weighed in lower than the final years of the the C3 at 3,239 lbs. and THAT dropped to 3,211 lbs with the L-98 introduction in 1985.
The C4 ushered in a historic time that saw the introduction of a new automotive component; the ECM. The industry was learning how to use this little dedicated computer to improve performance while at the same time, reducing emissions. The result was a SLOW increasing HP trend that was the opposite direction of that of the C3. Unfortunately, the new L-98 torque monster (a quote from European Jounralists who drove the fleet of C4s during its introduction on challenging mountiain roads in Europe) wasn't ready for the 1984 introduction. But in 1985, C4 year two, it was welcomed with the exuberance Corvette faithful who were excited to see the HP move up to 230 HP from the previous 205 HP crossfire. 1987 brought 240 HP, 1989 245HP, 1991 250HP. 1992 introduced the new LT-1 with 300 HP AND a new ZR1 model with DOHC and 375HP. The ZR1pealed at 400 HP and the LT 1 at 330 HP.
Every bit as important as the continual increases - mostly small increases - was the handling level McCellan gave the C4. Car magazine journalists from both North America AND European raved about the solid, predictable handling. You might say it handled too well for its own good. In 1988 the SCCA, responding to complaints from Porsche and others, banned the C4 Corvette from its races. Why? Because Porsche 944 and other sports cars had been beaten in almost every weekend event since the C4 was released. The C4 was DOMINANT (READ the link below to see the details). So make no excuses or qualifications for the C4 VERUS its contemporary competition and allow no slander! Low horsepower vs today? True...and the Romans were weak because they didn't have tanks and air support.
The C4 handled like a slot car and had the most controllable cornering fishtail of all my Vettes - unless I turn off the traction control on the C6. Even then my C4 might be more fishtail fun. Sadly, it creaked like a 200-year-old haunted house - more about that later. Happily, the seats had tremendous lateral support and great adjustable lumbar support.
McClellan's pride had two large faults.
1) Ferrari introduced their Targa top 308 in 1977. However, Magnum PI debuted in Dec 1980 and was a big hit in 1981. GM Marketing went to the top powers that be and said that the upcoming new generation Corvette MUST have a one-piece Targa top. Thanks largely to the aftermarket and to Magnum's Ferrari 308, the T-Top had lost so much status that, per GM Marketing that it was perceived as being old, out of date (or even *******) tech. McClellan was told to change it and don't delay the introduction. He did all that he could, but the debut was delayed. The official reason per the GM press release for the delay was: "...problems with parts supplier quality issues and production line changeover issues." They did NOT mention that the underlying cause was the change in the Bills of Materials because of the change in tops. It would not be completely inaccurate to say that the Targa top is the real reason there was no 1983 Corvette.
WHY was the C4 debut delayed...really?
Since day 1 of design, the C4 had undergone all testing and development with the t-top crossbar in place. To say McClellan was frustrated by this 11th-hour change would be a gross understatement. Nevertheless, his team set about making all the required changes, getting new parts, re-assembling, and then re-tuning the suspension. McClellan cut the T bar out, enlarged and raised the sides of the frame to the height of the seat edges and various other areas were also reinforced. The biggest solution was the Targa top FRAME was enlarged, made stronger, and changed to BOLT /Screw into place. Still, there was some minimal flex with the top on but LOTS of flex with the top unbolted. They kept working on this issue and by 1987 they were offering a Z52 option that added more reinforcements for the frame. My 87 was a Z52 but even when new, it flexed SIGNIFICANTLY over speed bumps with the top stored out back.
2) Partly because of #1 above and partly because of the clean sheet challenges, the C4 had a LOT of parts, and not all were as smartly designed as they could have been. Hindsight tells us that the C5 has 1500 fewer parts than the C4 despite the C4 being lighter than the last years of the C3. The clamshell hood looked slick and advertised the 'beautiful' aluminum suspension and fiberglass spring but the hood was VERY heavy in order to hold up to closing [heavy hood+heavy fender-tops + hood = clamshell]. The hatch glass had to be VERY thick for the same reason (subsequent years used thinner glass mounted to a composite hatch frame). The interior used way too many overlapping panels that rubbed and squeaked against each other over time.
The C4 was a sales leader in its class when it came out ... even against its world-class contemporaries. In the early 1990s several Asian and European models were retooled to try to steal buyers from Corvette and they did. GM responded only with some VERY mild exterior and a significant interior makeover. However, in 1990 GM did go all in on a top model DOHC ZR1 but overpriced significantly. It did come loaded but at $59k the ZR1 option was 60% of a loaded base car price added, so it did not sell well. Its best year was its first year with 3,049. Although it delivered world-beating performance, the ZR1 required a LOT of Engineering development resources and delivered very few units sold. A BAD formula for driving profits. Because of this, it actually hurt Corvette's bottom line and provided fodder for internal GM critics of Corvette. Even the slight mid-life refresh of the base C4 was not helping unit sales as the C4 entered the Winter years of its LONG 12-year life.
During those years, Dave Hill (Mc Clellan's successor) was covertly (even hiding activities from GM upper management) working on the C5 as he targeted every C4 weakness that he AND OWNERS, could identify. Hill stopped the Corvette cancellation threat the second time almost as surely as Zora saved it in the 50s.
The bottom line is that Both the C3 and the C4 were huge performers and sellers in their early years. But GM made the same mistakes with the C3 and the C4: They tried to extend the platform lives far too many years and sales dried up near the end of life.
The C4 ushered in a historic time that saw the introduction of a new automotive component; the ECM. The industry was learning how to use this little dedicated computer to improve performance while at the same time, reducing emissions. The result was a SLOW increasing HP trend that was the opposite direction of that of the C3. Unfortunately, the new L-98 torque monster (a quote from European Jounralists who drove the fleet of C4s during its introduction on challenging mountiain roads in Europe) wasn't ready for the 1984 introduction. But in 1985, C4 year two, it was welcomed with the exuberance Corvette faithful who were excited to see the HP move up to 230 HP from the previous 205 HP crossfire. 1987 brought 240 HP, 1989 245HP, 1991 250HP. 1992 introduced the new LT-1 with 300 HP AND a new ZR1 model with DOHC and 375HP. The ZR1pealed at 400 HP and the LT 1 at 330 HP.
Every bit as important as the continual increases - mostly small increases - was the handling level McCellan gave the C4. Car magazine journalists from both North America AND European raved about the solid, predictable handling. You might say it handled too well for its own good. In 1988 the SCCA, responding to complaints from Porsche and others, banned the C4 Corvette from its races. Why? Because Porsche 944 and other sports cars had been beaten in almost every weekend event since the C4 was released. The C4 was DOMINANT (READ the link below to see the details). So make no excuses or qualifications for the C4 VERUS its contemporary competition and allow no slander! Low horsepower vs today? True...and the Romans were weak because they didn't have tanks and air support.
The C4 handled like a slot car and had the most controllable cornering fishtail of all my Vettes - unless I turn off the traction control on the C6. Even then my C4 might be more fishtail fun. Sadly, it creaked like a 200-year-old haunted house - more about that later. Happily, the seats had tremendous lateral support and great adjustable lumbar support.
McClellan's pride had two large faults.
1) Ferrari introduced their Targa top 308 in 1977. However, Magnum PI debuted in Dec 1980 and was a big hit in 1981. GM Marketing went to the top powers that be and said that the upcoming new generation Corvette MUST have a one-piece Targa top. Thanks largely to the aftermarket and to Magnum's Ferrari 308, the T-Top had lost so much status that, per GM Marketing that it was perceived as being old, out of date (or even *******) tech. McClellan was told to change it and don't delay the introduction. He did all that he could, but the debut was delayed. The official reason per the GM press release for the delay was: "...problems with parts supplier quality issues and production line changeover issues." They did NOT mention that the underlying cause was the change in the Bills of Materials because of the change in tops. It would not be completely inaccurate to say that the Targa top is the real reason there was no 1983 Corvette.
WHY was the C4 debut delayed...really?
Since day 1 of design, the C4 had undergone all testing and development with the t-top crossbar in place. To say McClellan was frustrated by this 11th-hour change would be a gross understatement. Nevertheless, his team set about making all the required changes, getting new parts, re-assembling, and then re-tuning the suspension. McClellan cut the T bar out, enlarged and raised the sides of the frame to the height of the seat edges and various other areas were also reinforced. The biggest solution was the Targa top FRAME was enlarged, made stronger, and changed to BOLT /Screw into place. Still, there was some minimal flex with the top on but LOTS of flex with the top unbolted. They kept working on this issue and by 1987 they were offering a Z52 option that added more reinforcements for the frame. My 87 was a Z52 but even when new, it flexed SIGNIFICANTLY over speed bumps with the top stored out back.
2) Partly because of #1 above and partly because of the clean sheet challenges, the C4 had a LOT of parts, and not all were as smartly designed as they could have been. Hindsight tells us that the C5 has 1500 fewer parts than the C4 despite the C4 being lighter than the last years of the C3. The clamshell hood looked slick and advertised the 'beautiful' aluminum suspension and fiberglass spring but the hood was VERY heavy in order to hold up to closing [heavy hood+heavy fender-tops + hood = clamshell]. The hatch glass had to be VERY thick for the same reason (subsequent years used thinner glass mounted to a composite hatch frame). The interior used way too many overlapping panels that rubbed and squeaked against each other over time.
The C4 was a sales leader in its class when it came out ... even against its world-class contemporaries. In the early 1990s several Asian and European models were retooled to try to steal buyers from Corvette and they did. GM responded only with some VERY mild exterior and a significant interior makeover. However, in 1990 GM did go all in on a top model DOHC ZR1 but overpriced significantly. It did come loaded but at $59k the ZR1 option was 60% of a loaded base car price added, so it did not sell well. Its best year was its first year with 3,049. Although it delivered world-beating performance, the ZR1 required a LOT of Engineering development resources and delivered very few units sold. A BAD formula for driving profits. Because of this, it actually hurt Corvette's bottom line and provided fodder for internal GM critics of Corvette. Even the slight mid-life refresh of the base C4 was not helping unit sales as the C4 entered the Winter years of its LONG 12-year life.
During those years, Dave Hill (Mc Clellan's successor) was covertly (even hiding activities from GM upper management) working on the C5 as he targeted every C4 weakness that he AND OWNERS, could identify. Hill stopped the Corvette cancellation threat the second time almost as surely as Zora saved it in the 50s.
The bottom line is that Both the C3 and the C4 were huge performers and sellers in their early years. But GM made the same mistakes with the C3 and the C4: They tried to extend the platform lives far too many years and sales dried up near the end of life.