Z06 Retrospect From Racer Kit To Corvette Performance Icon

The C7 Z06 was much anticipated and did not disappoint. In the Z06 section of the 2015 Corvette brochure it says, “Your road-legal C7.R is ready.” - Road & Track. Indeed, the C7 Z06 has more race car built into it than any production Corvette ever. But it wasn’t always this way. Let’s go back to the beginning to see how we got here.

It all goes back to the 1957 AMA Racing Ban that GM agreed to honor. Duntov wanted to build purpose-built race cars under the Corvette name, as was done with the ’57 Corvette SS. He wasn’t keen on racing production Corvettes, but did the best he could with what he had. From 1957-1962, Duntov offered “Racer Kits” with Chevrolet-engineered performance suspension and brake parts to be used with their top fuel-injection engines. The plan worked because by the late ’50s Corvettes were winning races. In 1961, the Grady Davis Gulf Oil Corvette won the B/Production championship and in 1962 Davis’ Corvette won the A/Production championship. For the ’63 Sting Ray, Duntov created a similar suspension and brakes kit called RPO Z06. Knock-off wheels were included and the L84 327 fuel-injection engine was mandatory. Duntov added another endurance racer option: RPO N03, the 36-gallon fuel tank. Only 199 ’63 Corvette Z06s were built and just 63 with the big tank option. The package was very expensive, costing $1,818 plus $430 for the L84 engine, $188 for the four-speed transmission and $43 for the Posi rear. And unlike modern Z06 Corvettes, there were no external markings or badges.

The Z06 Corvettes would have been successful race cars had the Shelby Cobras not arrived. Of all of the ’63 Z06 Corvettes that raced, the Grady Davis car won races, but no championships. The Z06 option was dropped after the 1963 model year. Duntov quietly went to work on the new disc brake system, the big-block for the Corvette, and later the L88 racer kit package. Except for early Sting Ray racing fans, the Z06 name quickly disappeared from the collective memory. That is, until 2001.

For decades, Corvette racing fans had been lusting for a stripped Corvette that could be easily turned into a race car. The C5 was the most revolutionary new Corvette ever offered up to that point. Everything was new and greatly advanced over the C4: the all-new fuel-injected LS1 engine, transaxle, front mid-engine location, stiff hydroformed frame and more. With the excellent new platform, Chief Engineer Dave Hill and his team explored the concept of a reduced cost Corvette and came up with the ’99 fixed roof coupe model, based on the convertible model but with a bolted on and bonded hardtop. Unfortunately, the hardtop was only $394 less than the base model coupe and offered no performance advantage. In 1999, 4,031 hardtops were sold and in 2000 just 2,090 were sold. However, engineers noticed a 14 percent increase in overall chassis stiffness with the hardtop bonded in place.

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As every racer knows, a stiffer chassis better allows the suspension to do its work. Since there hadn’t been a performance Corvette since the ’95 ZR-1, the decision was made to make the hardtop into the new performance Corvette. Product planners went all the way back to the cool-sounding Z06 nomenclature, and thus the Z06 was reborn. Unlike the ’63 Z06, the ’01 Z06 would be an in-your-face Corvette.

Under the hood the basic LS1 engine received an improved air cleaner; new intake and exhaust manifolds; larger fuel injectors; a performance cam; high-rate valvesprings; new cylinder heads; a new PVC system and a lightweight, titanium exhaust system. The improved engine was christened LS6 and was rated at 385 horsepower and 385 lb-ft of torque. The six-speed transmission had revised gear ratios.

The Z06’s FE4 suspension included larger, hollow stabilizer bars; a stiffer rear spring and revised camber settings. The Z06 road on unique wheels that were 1-inch wider than the base wheels and were shod with Goodyear Eagle F1 Supercar tires. In addition to the hardtop’s unique profile, the Z06 received stainless steel mesh inserts into the front grille and side vents, and rear brake cooling scoops were added in front of the rear wheel openings. The overall look was serious. And the Z06 was bargain-priced, costing $47,500, just $7,025 more than the base Corvette. The new Z06 was quicker and faster than the $68,043 ’95 ZR-1. From 2002-2004, the Z06’s LS6 engine was rated at 405 horsepower. Yes, the Z06 was the new standard for performance Corvettes.

As awesome as the C5 Z06 was, when the C6 Z06 debuted, heads exploded. The C6 was an evolutionary Corvette; basically the same design, only much improved. The C5-R Corvettes were essentially test labs for the new C6. Never before had so much “race car” been poured into a production Corvette, and it all showed in the new Z06. The two big improvements were the all-aluminum frame and the new 427-cid, 505-horsepower, 470 lb-ft of torque LS7 engine with a dry-sump oil system. The 427 LS7 was essentially a maxed out LS6 that used pressed-in steel cylinder liners, titanium connecting rods and intake valves, 11:1 compression, and eight-quart dry-sump oiling system with a remote reservoir, and had a 7,000-rpm redline. The all-aluminum frame was a modern marvel of engineering that included magnesium fixed roof panel and engine cradle. The Z06 looked like it was on steroids. The front bumper cover fascia was unique with a simulated nose scoop, a front air splitter, larger front fender vents, flared carbon-fiber front and flared rear fenders, and a rear brake scoop just ahead of the rear wheel opening. Brakes were larger and thicker all around with larger six-piston calipers up front and larger four-piston calipers in the rear. Dedicated 10-spoke wheels shod with Goodyear Eagle F1 Supercar tires, 275/35ZR18 in front and 325/30ZR19 on the rear. The total weight of the Z06 was just 3,130 pounds.

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The new C6 Z06 delivered 0-60 times around 3.5 seconds and 11.5 seconds in the quarter-mile. Many customers that had owned older performance Corvettes quickly realized that the new Z06 was a beast on the track that had tremendous grip until it didn’t. However, most owners learned that if driven conservatively, their Z06 could be a comfortable street machine. Through the C6 run, the hand-built LS7 remained unchanged. As the C6 generation progressed, Chevrolet released seven distinctive special edition Z06 Corvettes. The Z06 body panels became the basis for the stunning ZR1 launched in 2009 and the successful Grand Sport that was launched in 2010.

The Z06 is now a permanent fixture in the Corvette community as the Corvette track car. The C7 Z06 was indeed a shocker, but not just because of its 650-horepower and 650 lb-ft of torque supercharged LT4 engine and hyper-aggressive looks, but for the first time ever, the Z06 was available as a coupe or a convertible. The base C7 comes with an all-aluminum frame that is stronger than the C6 Z06’s frame and is the same frame used on the C7.R cars, with enough structural rigidity to allow for a convertible version, as well as the coupe. The new Z06 was co-developed with the C7.R and has the optional Z07 Performance Package and is also available with an eight-speed paddle-shift automatic transmission that is quicker than the manual transmission Z06. The fenders are flared 80 mm on the front and 56 mm on the rear to cover wider lightweight wheels shod with Michelin Pilot Super Sport ZP summer-only tires. Brembo brakes are standard. All air intake and vents are larger for additional airflow to the engine, brakes and transmission and differential coolers. Like the C6 LS7, the LT4 engine has a dry-sump oil system and titanium connecting rods and intake valves. The ’15 Z06 finally became a member of the 2-Second Club, posting an official 0-60 time of 2.96 seconds. The official quarter-mile time is 10.95-seconds.

With a staggering array of options—including wheel designs and finishes, brake rotor colors, body stripes, aero packages, three interior trim levels and color combos, 10 exterior colors, all available in the coupe and convertible—the C7 Z06 is the most impressive Z06 ever offered. The basic ’15 Z06 started at $78,995 for the coupe and $83,995 for the convertible. That’s a $29,000 premium over the base model 2015 coupe, but this is as close to a C7.R as you can get, plus all the wonderful creature comforts. If one maxed out the options, the price would be close to $100,000. Starting in 2019, the ultra-exotic ZR1 will be the C7 supercar Corvette, but that doesn’t diminish the Z06. Duntov never imagined what his ’63 Z06 racer kit would become. Vette

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Illustrations by K. Scott Teeters

Source : http://www.superchevy.com/features/1805-z06-retrospect-from-racer-kit-to-corvette-performance-icon/

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