Corvette Z06 Fires Up New 7.0-litre V8

By Feann Torr - 19/01/2005

Four hundred and twenty seven cubic inches - or about 7.0-litres in the new money. That's how large the new Corvette Z06 supercar's engine is.

Spotted at the 2005 North American International Auto Show in Detroit, the new Corvette - which was unveiled in 2004 - sports a number of race track-inspired features, and of course that dirty great big motor.

Far from shy, the new powerplant that gives life to the Z06 - the sports variant of the Corvette, always has been, always will be - is called the LS7 by the company, which reckons the new model will be able to hit 100km/h from standstill in less than 4.0 seconds.

That's plenty quick. In fact that's supercar quick.

But before we look at the innards of GM's colossal new 427ci engine, which you can be sure HSV will be eyeing off for its next generation GTS, it should be known that the new Z06 is more than just a Corvette with an extra 1000cc of displacement.

"The new Z06 is the dividend from competing so successfully in endurance racing," said Dave Hill, Corvette's chief engineer.

"It combines the strong attributes of the new, sixth-generation Corvette with the spirit, technology and know-how from the race program to form an American supercar with outstanding credentials."

A fixed roof (with no targa panels) ensures the Z06 is more rigid (and aerodynamic) than even the Corvette coupe model, while an aluminium body structure with one-piece hydroformed perimeter rail frame and magnesium front cradle sounds quite cool, but it actually helps too, by lowering weight and increasing stiffness.

Exotic materials anyone? As well as magnesium and aluminium alloys, another lightweight material - carbon fibre - makes the Z06 cut.

Used in the front bumpers and wheel arches, the carbon fibre helps reduce weight in the front end , much needed when such a large engine lurks beneath, and again it increases rigidity. But remember that when it breaks, it shatters, so replacement costs rise significantly with the use of carbon fibre.

To help the brand-spanking LS7 engine breath, a new front fascia that incorporates a larger grille and lower air splitter (not to mention a cold-air scoop) are installed.

The Z06 is some 76.2 millimetres wider than the stock C6 Corvette and is fitted with acres of rubber for increased grip: 18-inch front wheels are shod with 275/35ZR tyres and the 19-inch rear wheels wear huge 325/30ZR tyres.

The new Z06 Corvette tips the scales at 1420kg, or about 3130 pounds, and was developed in tandem with the C6-R race car, and as a side note, last years racing Corvette, the C5-R, won every race in the 2004 season, which makes it the most successful era in Corvette's 50-year racing history. Not bad, eh?

But how about that engine? Displacing 7.0-litres, the Gen IV V8 (designated LS7) makes a whopping 373kW @ 6200rpm, or precisely 500 horsepower. So what exactly does having 500 ponies under the bonnet mean? To performance enthusiasts, very small numbers.

German and Italian supercar makers will be taking the new 2006 model Z06 very seriously, as Chevy reckons buyers of the bargain-priced $US70,000 beast will be able to post 0-100km/h times of under 4.0 seconds, eclipse the quarter-mile in less than 12.0 seconds and deliver a top speed of more than 190mph (306km/h) on a race track.

The new LS7 Gen IV aluminium engine measures a whopping 427 cubic inches and promises to give the world's best 8, 10 and even 12-cylinder powerplants something to mull over - forced induction or not. It generates an incredibly healthy 657Nm @ 4800rpm, which equates to about 475 lb.-ft. of torque. Whichever way you classify it, that's an astonishing amount of twist for a car that weighs less than 1.5 tonnes.

"In many ways, the LS7 is a racing engine in a street car," said Dave Muscaro, assistant chief engineer of small-block V8 for passenger cars. "We've taken much of what we've learned over the years from the 7.0-litre C5-R racing program and instilled it here. There really has been nothing else like it offered in a GM production vehicle."

Compared to the latest Italian supercars, the 2006 Corvette Z06 will offer solid competition, scoring well in most of the basic performance categories - at least on paper - including peak power, torque and the 0-100km/h dash. While it's powerplant is a good 2.0-litres larger than either the F430's or the Gallardo's, it's a much cheaper and more realistic purchasing proposition than either of the Italians.

Compared to the 6.0-litre LS2 V8 that powers standard C6 Corvettes and Australian-built HSV models, the bigger, badder 7.0-litre LS7 small-block V8 shares basic engine architecture with its smaller Gen IV sibling, but items such as new cylinder heads and block, plus super-strong titanium con rods and intake valves ensure that the engine can cope with high revs and big stress, often found at the race track. The redline is 7000rpm, with a fuel cut off kicking in at 7100rpm.

A high 11.0:1 compression ratio ensures rapid response and racing-derived CNC-ported aluminium cylinder heads with titanium intake valves and sodium-filled exhaust valves keep the combustion process regular.

At the rear of the engine resides a single-mass flywheel, in addition to a lightweight, high-capacity clutch.

GM's 6-speed manual transmission has been strengthened to handle the bigger engine's increased torque load, and it even includes a pump which sends transmission fluid to the front radiator for cooling. A slippery diff is also part of the package.

Hand built at GM's new Performance Build Centre in Wixom, Michigan, the new 7.0-litre mill is the most powerful passenger car engine the company has ever built, and as mentioned earlier, you can bet your bottom dollar that HSV is already lobbying brother-in-arms Holden to source a few pre-production donks for testing in its new GTS, which is likely to appear shortly after the next generation VE Commodore launches in 2006.

As well as rip snorting acceleratory performance, the new Z06 is expected to offer short stopping distances thanks to its upgraded braking package.

355mm cross-drilled front disc brakes are covered by six pot callipers, while at the rear 340mm cross- drilled discs are clamped by four piston callipers.

Furthermore, rear brake cooling ducts were added to the bodywork to ensure a constant flow of air to cool the rotors and calipers.

The 2005 Corvette Z06 will cost about $US70,000 and according to Chevrolet it is "...the fastest, most powerful car ever offered by Chevrolet and General Motors. It is comprised of an unprecedented level of capability and technology, making it one of the greatest performance values on the market. And with an unmistakably muscular appearance, the 2006 Z06 has a visual attitude that always looks ready to demonstrate Corvette's winning attitude to any challenger around the globe."

Unfortunately for those of us living in Australia, the Z06 is a left-hand driver, and right hand drive models are not yet in the pipeline. Even so, the new Z06 is still quite the piece of thoroughbred kit, with a wider body, a subtle new look, race-tuned suspension, fatter rubber, bigger brakes and of course that engine.

Indeed, the 2006 Corvette Z06 is arguably one of the most desirable two door sports car to come out of the US, and could force other exotic automakers to design more cost effective models as a result. Developed in conjunction with its C6-R race car, could the Americans finally have the measure of the European exotics?