The 1986 Corvette

The Overview

The 1986 Corvette is the year the C4 grew up: the convertible returned, anti-lock brakes and a theft-proof key became standard, and the L98 got the aluminum heads it had been designed for. The convertible was engineered with the American Sunroof Company and built at Bowling Green: an X-brace tying the door-hinge pillars to the rear torque boxes, K-braces under the engine, a stiffer cowl, steering-column and dash beam, a crossbeam at the rear torque box and a double-wall steel riser behind the seats made the open car more rigid than the coupe for about fifty pounds, with a manual top under a hard cowl and the high-mounted stop lamp moved from the hatch to the rear fascia. It cost $32,032, $5,005 more than the $27,027 coupe and the first Corvette past $30,000, and 7,315 were sold against 27,794 coupes.

Chevrolet put a yellow convertible on the Indianapolis Motor Speedway on May 31, 1986, with General Chuck Yeager driving, and because the car needed nothing but strobes, harnesses and a fire system to pace the field, declared every 1986 convertible an Indy 500 Pace Car; there was no package or price, only dealer-supplied door decals for the owners who wanted them, which is why “Pace Car Edition” in a listing today means a convertible of any color with the decals on. Under the hood, the Tuned-Port 350 picked up aluminum cylinder heads with centrally located copper-core plugs, bigger intake ports and sintered valve seats, raising compression to 9.5:1 and output from 230 to 235 hp; the first heads cracked at the bolt bosses in durability testing, so the thicker production heads arrived late and early coupes kept cast iron while every convertible got aluminum. Bosch ABS II anti-lock brakes became standard on every Corvette, and so did VATS, the Vehicle Anti-Theft System that read a resistor pellet in the key and shut down the starter and fuel pump for minutes if it saw the wrong one, cutting theft from seven percent of C4s to under one and insurance premiums by a fifth.

The rest was detail: caster up to six degrees for straighter tracking, the standard tire narrowed to P245/50VR16 (Z51 coupes kept the P255s), a three-converter exhaust, an upshift light and re-angled LCD gauges, wheels with raised hub emblems and a brushed finish, and the fifty Malcolm Konner Commemorative Edition coupes in Silver Beige over Black (RPO 4001ZA, $500), the only time GM built a special edition for a single dealer. Road & Track’s coupe ran 0–60 in 5.8 seconds and the quarter in 14.4 at 96 mph and pulled 0.91 g; production fell for the second year to 35,109. Today the 1986 is the C4 to buy for a convertible on a budget, and the Pace Car replicas are the first C4s with a collector following, with low-mileage yellow cars and 4+3 manuals bringing the most.

The 1986 Corvette Story

For those that lived through that era, 1986 probably resonates as one of the most innovative and exciting years of the entire decade. It was the year the Human Genome Project was first proposed, the effort that would map the genetic structure of the human body. IMAP, the protocol that still delivers much of the world’s e-mail, was written. IBM unveiled the PC Convertible, its first laptop computer.

And, in its own way, General Motors was also pioneering new territory as they continued the evolution of their famous sports car. With the continual refinement of their L98 engine, a bigger focus on safety and security, and the development of many new functions and luxury features, the arrival of the 1986 Corvette carried with it the continuation of the spirit of innovation that had helped Corvette rise to become a world leader in the sports car market since its humble beginnings in 1953.

Since the introduction of the C4 Corvette in 1984, a significant increase in Corvette theft had been reported all across the country. Of all the Corvettes built in 1984 and 1985, approximately 7 percent had been stolen. Recognizing a need to make their cars more secure for the customers who were purchasing them, General Motors introduced a new security technology as a standard feature on all Corvettes.

“VATS” or “Vehicle Anti-Theft System” was a simple but effective addition to the existing alarm system. A small metal pellet with a specific electrical resistance was embedded in the ignition key, and had to be read by a hidden, electronic “decoder” before the engine could start.

Using the wrong key would cause the decoder to shut down both the starter relay and the fuel pump for a minimum of two minutes (although there are recorded incidents where the car would remain immobilized for as long as 15 minutes) before allowing the operator another attempt at starting the car. After the introduction of the VATS system in 1986, Corvette theft dropped from 7% to less than 1% in 1986 and to near 0% by late 1987 /early 1988.

The results were significant enough to prompt many automotive insurance companies to reduce their comprehensive premium rates for Corvettes equipped with VATS by 20-25 percent.

Another advancement of the 1986 model year involved the introduction of the first anti-lock braking system to the Chevrolet Corvette. Anti-lock brakes (ABS), which used the latest ABS II setup from Bosch in Germany, prevented wheel lock up in extreme braking conditions and reduced/eliminated skidding and subsequent loss of control of the car. ABS was relatively new in 1986 and its usage was limited mainly to high-cost luxury cars. Although no additional changes were made to the Corvette’s braking system, the addition of the ABS helped the Corvette further gain acceptance as the true world-class sports car that Chevy said it was.

Still other, less notable (but equally significant) changes were made. Under the hood, the L98 engine received an upgrade when the cylinder heads were changed from cast-iron to aluminum, taking weight off the nose.

The first aluminum heads were found to be too thin during durability testing, cracking around the head-bolt bosses under high engine loads, so production heads had to be thicker, and their arrival was delayed until well into the model year: early coupes kept the cast-iron heads while every convertible and the later coupes got aluminum. The new heads carried centrally located copper-core spark plugs for better combustion, larger intake ports and sintered-metal valve seats, and raised the compression ratio to 9.5:1. Engines fitted with aluminum heads were rated at 235 horsepower, five more than the 1985 and the early-1986 iron-head cars.

Did you know? Fifty 1986 Malcolm Konner Commemorative Edition Corvettes were built in a special arrangement honoring the New Jersey Chevrolet dealership's founder, Malcolm Konner. Each Corvette was painted a two-tone paint scheme: Silver Beige over Black. Window stickers reflected 4001ZA as the RPO, and a $500.00 cost was listed for MALCOLM KONNER SP. EDIT. PAI (Malcolm Konner Special Edition Paint). All of the Malcolm Konner Special Edition cars were coupes. Twenty were built with manual transmissions while the other thirty were fitted with automatics. All had graphite leather interiors.

Other mechanical changes were made to the Corvette as well, though none provided any performance improvement.

Amongst these changes, the exhaust system was revised, introducing triple catalytic converters to meet the ever increasing Federal emissions standards that were put into place for 1986.

Caster was increased from 3.8 degrees to 6.0 degrees to improve on-center road feel and to decrease wander. The standard tires were changed to P245/50VR16s, a size narrower than the P255s every 1984 and 1985 had worn.

However, for the Z51 package, the tires continued to be P255s. The overall size of the fuel tank was reduced by two gallons on automatic Corvette models.

Cosmetic, but functional, changes were also introduced on the 1986 Corvette. Above the rear hatch window, a high-mounted stop lamp was added. This brake light, which was introduced to meet a new federal requirement, was a key distinguishing feature of the 1986 Corvette, as it was one of the few outward changes that was made to the C4 since its introduction in 1984.

Elsewhere, small changes appeared throughout the car. In the cockpit, the LCD instruments were re-angled to aid in daytime legibility. Despite the re-angling, the digital dashboard continued to be a problem during daytime operation of the Corvette.

New to the dash cluster in ’86 was the introduction of an upshift indicator light which was intended to help drivers achieve maximum fuel mileage by signaling the optimal time to shift gears during vehicle operation.

While considered an unnecessary feature by many consumers, its intent was to help keep the car’s EPA mileage figures above the gas-guzzler level. (As an interesting side note, the shift indicator light was tied into all automatic transmissions as well.)

Additionally, “low coolant” and “anti-lock” (in reference to the anti-lock brakes) instrument displays were also added. Wheels were given raised hub emblems and a bright brushed finish which replaced the black centers of the 1984 and 1985 models.

But for all of this, the most significant change didn’t come as an optional component, but rather as an entirely optional model type – the Corvette Convertible. Chevrolet engineers, aided in part by engineers from the American Sunroof Company (ASC), had stated that the C4 Corvette’s design had always been intended to support a convertible variant of the beloved coupe, and so they knew that transforming the car from coupe to convertible would be a straightforward process. Because the absence of the roof pillar (and other supporting hardware) would increase body flex in the car, reinforcement was applied to the frame cross member in front of the engine. Larger X-braces were added to tie door-hinge pillars to the rear chassis torque boxes and larger K-shape braces were used to connect the under engine member to the frame rails. Additional structural reinforcements were added to the cowl structure, including the steering column, its mounts, the front torque box and the dashboard mounting beam. Similarly, a crossbeam was added to the rear torque box, and the steel riser behind the seats became a sturdier, double-wall structure.

Subtle cosmetic changes were made for the convertible as well, although the Corvette maintained a clear likeness to its coupe counterpart. For one, the rear center taillight was moved from the rear deck lid glass and was instead inserted in the upper center of the rear bumper fascia, just above the rear Corvette nameplate. For another, the cockpit featured a cowling that discreetly covered the convertible top, giving the 1986 Corvette an appearance that was as much “roadster” as convertible.

The new Corvette convertible was only fifty pounds heavier than the coupe and, because of the careful attention spent in reinforcing its structural design, was actually more rigid than the coupe, proving that the convertible could be as competitively functional as the coupe. Of course, this type of additional innovation carried additional cost, and the convertible Corvette was no exception. Its introduction in 1986 was accompanied by a $5,005 premium over the coupe.

The arrival of the convertible brought with it Corvette’s return to Indianapolis. Although the announcement came late in the automotive season, its introduction occurred in time for the Corvette to be invited to participate in that year’s Indianapolis 500 as the official Pace Car. The 1986 Corvette convertible would become the second Corvette in history (second only to its 1978 forerunner) to serve as a pace car at the Indianapolis 500, and Chevrolet was more than proud that its two-seat convertible needed no special performance or engineering modifications to help the car reach the necessary speeds to lead a field of race cars around the famous Brickyard racetrack. With the exception of safety-conscious strobe lights, a pair of five point harnesses (driver and passenger), and an onboard fire system, the yellow, 235-horsepower convertible that led the pace lap on May 31, 1986 was nearly identical to all other Corvette convertibles sold to the public that year.

Although the actual pace cars were painted a bright yellow and wore special “Official Pace Car” badges, General Motors deemed that every Corvette convertible built in 1986 would be a street-going Indy pacer, regardless of color. In fact, no special limited-edition “pace car” package option was ever offered, but instead, buyers were given the option of adding dealer-supplied commemorative decals to the doors of their 1986 Corvette.

Interestingly, the arrival of the new Corvette Convertible in 1986 resulted in less than stellar sales. Probably due in large part to “sticker shock”, only 7,315 Corvette convertibles were sold that year. While there was certainly no question that Corvette engineers, workers and fans alike welcomed back the nostalgia-filled convertible, its price proved to put the car just out of reach for most consumers looking to purchase a convertible sports car that year.

Production Volumes

The Z51 Performance Handling Package, taken by 12,821 buyers, was offered only on the coupe: even with its X-member reinforcement, the convertible chassis was not offered with the bone-jarring Z51 suspension.

In all, 35,109 Corvettes were sold in 1986. While this number was still considered to be very respectable, it was the second year in a row that overall Corvette sales numbers had slipped. Despite these diminished numbers, there was no question that Corvette was continuing to move in the right direction.