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Rob
01-31-08, 11:45 PM
The king of all corvettes

Posted By JEFF MELNYCHUK
St. Catharines Standard

We've never been more excited about a car that we know so little about, one that we've never driven.

There's no pricetag, no projected availability, no concrete performance data and no exact horsepower rating.

And we love it.

Blame our excitement about the new Corvette ZR1 on the current and spectacular ZO6 model, a car that acts in many ways as the jumping-off point for the ZR1. The new 'Vette is Chevrolet's answer to the 600-horsepower Dodge Viper and just about every other so-called performance machine built anywhere on this or any other planet.

The ZO6's 505-horsepower 7.0-litre (427-cubic-inch) V8, aluminum chassis, broader-by-eight-centimetres hind section and near-200-mph (320 km-h) top speed make it a total kick to drive and a handful if you don't have a healthy respect for this two-seater's capabilities. Many people would argue that it's the best performance value out there, as would we.

Then there's the ZR1.

The very name has been a source of debate for the better part of a year, actually ever since GM boss Rick Wagoner wondered what a US $100,000 Corvette would look like. As with the ZO6 name, Chevrolet dug into the 'Vette's history to pluck the ZR1 badge, one that was attached to the high-performance model from the early 1990s. While the name isn't particularly inspiring and is far from original, the car itself is another matter altogether.

The base Corvette uses a steel frame while the ZO6's is made of lightweight aluminum. This race-proven design is also used for the ZR1 although the engine of choice is loosely based on that of the base 'Vette and not the ZO6. Called the LS9, the ZR1's engine displaces 6.2 liters rather than 7.0 for the ZO6 and makes 620-plus horsepower (compared to the ZO6's 505) and about 600 pound-feet of torque thanks to a supercharger that forces in additional air/fuel mixture to the tune of 10.5 pounds per square inch. Built by Eaton, it's a revision on the tried-and-true Roots-type supercharger that uses long paddles, each with four lobes, that mesh together to move the air, compressing it as the paddles rotate. It bolts to the top of the engine and is aided by two intercoolers that lower the intake-charge temperature.

Yes, the all-aluminum engine block is stronger and the cylinder heads are specially designed with larger valves and are cast from aircraft-grade aluminum. And the crankshaft is forged steel while the connecting rods are made of titanium. All are designed for an end result, according to General Motors, of much more low-speed power than the brute force supplied by the ZO6 and much more top end punch. Redline is 6,500 rpm.

Normally, the supercharger belt only runs the supercharger. In the case of the ZR1, it also runs the accessories, which makes for shorter overall engine length, helpful considering the tight quarters under the hood of the Corvette.

An updated six-speed manual transmission has been toughened up to take the additional load while a special clutch adds more clamping force.

Large 19-inch front wheels and 20-inch rears mount specially designed Michelin Pilot Sport PS2 tires, 285-millimeter section width in front and 335 mm out back, slightly wider than what you'll find on the ZO6, which also uses smaller 18- and 19-inch-diameter wheels.

A specially programmed version of Chevrolet's magnetic ride control, which constantly varies the shock absorber dampening by changing the electrical current traveling through what amounts to liquid metal, apparently allows for even higher performance levels than the ZO6 while providing a softer ride closer to that of base Corvettes.

The ZO6's brakes are fantastic, but the ZR1's rotors are substantially larger (395 mm in front and 380 mm out back compared to 355 and 340, respectively) and lighter thanks to carbon-ceramic composition (usually seen on race-only applications) rather than cast iron. GM reports the weight savings to be 4.75 kilograms per rotor over similarly sized iron discs. The brake pad surface area of the ZR1 is double that of the ZO6. Carbon ceramic is so good at shedding heat and is so wear resistant that the rotors will most likely never need replacement under normal use, whatever defines "normal" in the ZR1's case.

For the body, special lightweight carbon-fibre front fenders - wider than those found on the ZO6 - with dual side air extractors, exposed-weave carbon-fibre roof panel (light at just three kilograms and racy looking, too) and carbon-fibre chin spoiler (often referred to as a splitter) are the most visible additions. And then there's the bulging carbon-fibre hood with a clear window that reveals the intercoolers.

Despite all the lightweight bits and pieces, the ZR1, at a projected 3,350 pounds (1,520 kilograms), is about 190 pounds (85 kilograms) heavier than the ZO6.

There's ZR1 badging in key locations and the interior is your basic ZO6 layout although the gauge cluster is updated with a boost gauge for the supercharger and a speedometer good for 220 mph (350 km-h). Get your ZR1 in one of seven colours.

With the extra work Chevrolet has done over and above the already-fantastic ZO6, it probably doesn't really matter just how much better the ZR1 is. It just is and that's what has us excited. Just wait until we drive one.