Blown_SC
10-06-2005, 07:18 AM
2006 Corvette Z06 - A Civilized Supercar
By Gerry Malloy
--------------------------------------------------------------------------------
http://fp.images.autos.msn.com/merismus/gallery/c455953a.jpg
The all-new C6-based Corvette Z06 is a milestone car that combines everyday civility with true supercar performance at merely a luxury car price.
Overall rating: 9.2 / 10
Pros
- Exceptional acceleration and braking
- Race-car handling
- Everyday-driver civility
- Race-car-look styling
Cons
- 'Skip-shift' transmission function
- Low-luxe interior trim
- Some gear rattle evident
- Step-function tilt steering
Supercar Performance at a Luxury Car Price
Chevrolet's Corvette has always ranked high on the performance-to-dollar scale. With the new, C6-based Z06 model, it simply blows the top off that chart.
No production car on the planet comes close to providing the all-round performance capability of the Z06 at anywhere near the price. Even price-independent, it has to be one of the most desirable sports cars ever built, not the least because it combines truly explosive performance with a civility that belies that raw nature. This is a supercar you could live with every day.
While it looks like a modified version of the regular C6, almost every major component set in the car - from its structure to its engine to its brake system to its bodywork - is unique to the new Z06. Still, apart from the initial structural fabrication, the car is built on the same Bowling Green, Kentucky, assembly line as all other Corvettes.
While it is possible to buy a relatively low-featured version in the U.S., in Canada the Z06 comes in one flavour only - all dressed - with an MSRP of $89,900. For this report, I drove several examples of the car, on the road and on the track, at Virginia International Raceway.
Real Race-car Breeding
Many companies pay lip service to the influence of racing on their vehicles, but in the case of the Z06 that relationship is real, according to Corvette chief engineer Dave Hill. And it is a two-way street.
The aerodynamic development of the two cars was conducted concurrently, for example. So it is no accident that the Z06 looks a lot like the racer, from its splitter-like front air dam to its wide-flared fenders, front and rear, which accommodate both wider tires and a wider track. The deeper air inlet on the Z06's front fascia was adopted specifically to provide better engine cooling for the race car, which uses similar bodywork, and as on the racers, all the Z06's air inlets and vents are functional.
Where the two differ most dramatically is in the absence of a car-wide wing on the production model. Instead, the Z06 employs a short, wicker-like extension on the CHMSL (Center High-Mounted Stop Lamp) housing that is sufficient to provide the desired balance of front-rear downforce, according to Hill. Anything more would adversely affect the Z06's 0.34 drag coefficient.
The Quest for Balance
Balance was high on Hill's agenda during the development of the Z06. He wanted a supercar power-to-weight ratio, but rather than just increasing power he put an equal emphasis on reducing weight, and on redistributing it to achieve a 50/50 front/rear distribution.
It would be a tough challenge, for raising the overall performance bar to the next level would require bigger, heavier brakes for one thing: Much bigger, as in 14-inch (355-mm) rotors in front, 13.4-inch (340-mm) in the rear, all vented and cross-drilled. Six-piston Brembo calipers are used up front, four-pistons in the rear, with a separate pad for every piston to ensure optimum contact. Serious, serious brakes!
The wheels and corresponding tires are bigger, too - 275/35ZR18 in front; 325/30ZR19 in the rear. Evolutionary improvements in the Goodyear Eagle F1 Supercar run-flats enhance both performance and ride quality according to Hill.
More weight was added in the engine compartment in the form of a racer-derived dry-sump lubrication system, which prevents oil starvation under high cornering loads. The Z06 will pull 1.04 g laterally on a skid pad. To help balance that up-front weight addition the battery was moved to the rear of the car.
With those and other enhancements, the Z06 would have been substantially heavier than a regular C6 if countermeasures had not been taken.
Adding Lightness
Countermeasures were taken. For starters, the hydroformed steel frame rails of the C6's space-frame structure were reproduced in aluminium, and aluminium castings abound in the structure. A transverse tie-bar joining the A-pillars is the only remaining steel piece in the structure.
The cradle for the engine and front suspension is made of magnesium, as is a roof insert that turns the open-topped coupe into a fixed-roof version, improving overall structural rigidity. To further reduce weight, carbon-fibre is used to skin the car's unique balsa-core floors, and for the front fenders and hood, further tilting the weight balance toward the rear. Don't even think about replacement costs for those bits.
The net result of all that exotica is a mass of 1420 kg (3132 lb), 50.2 percent of which rests on the rear wheels with an average-sized driver on-board. That's 22 kg lighter than the barest of regular C6 coupes, and about 50 kg less than those typically equipped.
Power! Power! Power!
With the regular C6 making 400 hp, compared to the 405 hp peak of the previous Z06, Hill set an objective of 500 hp for the new car. GM's Powertrain engineers overshot his target, achieving 505 SAE-certified horsepower at 6300 rpm and 470 lb-ft of torque at 4800 rpm from the all-aluminium Gen IV small-block V8.
Some of those 100 additional horses come from a displacement increase from 6.0 to 7.0 litres - 427 cubic inches for those with a sense of Chevrolet history. But other racing-derived features also play a part. Things like CNC-ported cylinder heads, titanium connecting rods and intake valves, and sodium-cooled exhaust valves. The engine is hand-assembled to race-engine standards at GM's Performance Build Center in Wixom, Michigan
Increasing intake airflow through a 90-mm throttle-body and big, straight-shot intake ports and freeing up the exhaust with hydroformed four-into-one headers and three-inch exhaust pipes also provide some added power. An electronically-controlled valve in each muffler opens when engine-speed tops 3500 rpm, creating a wonderfully guttural roar, but I have it on good authority that disconnecting just the right wire keeps those valves open all the time.
On the Road
If you are judicious with application of the right pedal, driving the Z06 is little different than driving any other C6. Almost everything inside is the same apart from a revised gauge cluster and the seats. They feature fixed side-bolsters to better hold the driver in place, and the passenger's seat forfeits power controls to save a little more weight. Features such as HID lighting, fog lamps, leather seating, dual-zone air-conditioning, and head-up display (HUD) with track mode and g-meter are all standard.
GM says the Z06's acoustic package is also revised to reduce weight and "allow more aural feedback from the powertrain." Smart move, for even at idle, the sound of that seven-litre V8 burbling away like some reincarnated Can-Am racer is immensely satisfying. So is its part-throttle response, providing enough instant thrust for any conceivable real-world driving need.
As a highway cruiser the Z06 is comfortably benign but in the twisties it fairly comes alive, turning in sharply with a fluid ease that belies its size. If there is any body roll it is simply not evident, and even the ride quality is superior to that of many 'wannabe' sporty cars.
When you get tired of playing nice and want to nail the throttle … well, that's when it's time to start looking for a drag-strip, or a solo race, or track that offers lapping sessions.
On the Track
It is only on a track that one can come close to appreciating the brilliance of the Z06, or truly test its capabilities. On the tighter elements of VIR it reached what seemed like impossible cornering loads before the Active Handling System gently intervened. Resetting it to competition mode lets one hang the car out even further before saying "enough."
To my surprise, the front tires hung on tenaciously, permitting mid-corner adjustments with judicious use of the right foot, and it flicked its way through VIR's multiple esses with go-kart ease, rather than lurching from point to point as in some high-performance cars.
When I put my foot down coming off the corners, it was like pulling the release lever on my own personal catapult. Explosive is the only way to describe this car's acceleration ability.
GM says it will do 0-to-100 km/h in 3.9 seconds - delayed by the need for an upshift from 1st to 2nd gear just before reaching that speed - and it will run the quarter-mile in 11.7 seconds at 125 mph (201 km/h). Top speed is said to be 198 mph (319 km/h). I can't verify that number, but I can vouch for the fact that it is still pulling strong at 160 mph (257 km/h).
As for braking, I consistently underestimated the car's ability, braking way earlier than needed. It took a ride with Corvette racer Johnny O'Connell to learn just how good the brakes really are - incredible - and how far away from the car's ultimate limits I really was. My self-preservation instincts had automatically intervened well before I approached the car's ultimate limits. It takes a driver of considerable talent to get everything it has out of a Z06.
Conclusion
The 2006 Z06 is truly a milestone car and not just in terms of the exceptional performance of which it is capable. Its real achievements are combining supercar performance with a level of civility that surpasses that of many far lesser vehicles, and doing so at the price of a mere luxury car.
By Gerry Malloy
--------------------------------------------------------------------------------
http://fp.images.autos.msn.com/merismus/gallery/c455953a.jpg
The all-new C6-based Corvette Z06 is a milestone car that combines everyday civility with true supercar performance at merely a luxury car price.
Overall rating: 9.2 / 10
Pros
- Exceptional acceleration and braking
- Race-car handling
- Everyday-driver civility
- Race-car-look styling
Cons
- 'Skip-shift' transmission function
- Low-luxe interior trim
- Some gear rattle evident
- Step-function tilt steering
Supercar Performance at a Luxury Car Price
Chevrolet's Corvette has always ranked high on the performance-to-dollar scale. With the new, C6-based Z06 model, it simply blows the top off that chart.
No production car on the planet comes close to providing the all-round performance capability of the Z06 at anywhere near the price. Even price-independent, it has to be one of the most desirable sports cars ever built, not the least because it combines truly explosive performance with a civility that belies that raw nature. This is a supercar you could live with every day.
While it looks like a modified version of the regular C6, almost every major component set in the car - from its structure to its engine to its brake system to its bodywork - is unique to the new Z06. Still, apart from the initial structural fabrication, the car is built on the same Bowling Green, Kentucky, assembly line as all other Corvettes.
While it is possible to buy a relatively low-featured version in the U.S., in Canada the Z06 comes in one flavour only - all dressed - with an MSRP of $89,900. For this report, I drove several examples of the car, on the road and on the track, at Virginia International Raceway.
Real Race-car Breeding
Many companies pay lip service to the influence of racing on their vehicles, but in the case of the Z06 that relationship is real, according to Corvette chief engineer Dave Hill. And it is a two-way street.
The aerodynamic development of the two cars was conducted concurrently, for example. So it is no accident that the Z06 looks a lot like the racer, from its splitter-like front air dam to its wide-flared fenders, front and rear, which accommodate both wider tires and a wider track. The deeper air inlet on the Z06's front fascia was adopted specifically to provide better engine cooling for the race car, which uses similar bodywork, and as on the racers, all the Z06's air inlets and vents are functional.
Where the two differ most dramatically is in the absence of a car-wide wing on the production model. Instead, the Z06 employs a short, wicker-like extension on the CHMSL (Center High-Mounted Stop Lamp) housing that is sufficient to provide the desired balance of front-rear downforce, according to Hill. Anything more would adversely affect the Z06's 0.34 drag coefficient.
The Quest for Balance
Balance was high on Hill's agenda during the development of the Z06. He wanted a supercar power-to-weight ratio, but rather than just increasing power he put an equal emphasis on reducing weight, and on redistributing it to achieve a 50/50 front/rear distribution.
It would be a tough challenge, for raising the overall performance bar to the next level would require bigger, heavier brakes for one thing: Much bigger, as in 14-inch (355-mm) rotors in front, 13.4-inch (340-mm) in the rear, all vented and cross-drilled. Six-piston Brembo calipers are used up front, four-pistons in the rear, with a separate pad for every piston to ensure optimum contact. Serious, serious brakes!
The wheels and corresponding tires are bigger, too - 275/35ZR18 in front; 325/30ZR19 in the rear. Evolutionary improvements in the Goodyear Eagle F1 Supercar run-flats enhance both performance and ride quality according to Hill.
More weight was added in the engine compartment in the form of a racer-derived dry-sump lubrication system, which prevents oil starvation under high cornering loads. The Z06 will pull 1.04 g laterally on a skid pad. To help balance that up-front weight addition the battery was moved to the rear of the car.
With those and other enhancements, the Z06 would have been substantially heavier than a regular C6 if countermeasures had not been taken.
Adding Lightness
Countermeasures were taken. For starters, the hydroformed steel frame rails of the C6's space-frame structure were reproduced in aluminium, and aluminium castings abound in the structure. A transverse tie-bar joining the A-pillars is the only remaining steel piece in the structure.
The cradle for the engine and front suspension is made of magnesium, as is a roof insert that turns the open-topped coupe into a fixed-roof version, improving overall structural rigidity. To further reduce weight, carbon-fibre is used to skin the car's unique balsa-core floors, and for the front fenders and hood, further tilting the weight balance toward the rear. Don't even think about replacement costs for those bits.
The net result of all that exotica is a mass of 1420 kg (3132 lb), 50.2 percent of which rests on the rear wheels with an average-sized driver on-board. That's 22 kg lighter than the barest of regular C6 coupes, and about 50 kg less than those typically equipped.
Power! Power! Power!
With the regular C6 making 400 hp, compared to the 405 hp peak of the previous Z06, Hill set an objective of 500 hp for the new car. GM's Powertrain engineers overshot his target, achieving 505 SAE-certified horsepower at 6300 rpm and 470 lb-ft of torque at 4800 rpm from the all-aluminium Gen IV small-block V8.
Some of those 100 additional horses come from a displacement increase from 6.0 to 7.0 litres - 427 cubic inches for those with a sense of Chevrolet history. But other racing-derived features also play a part. Things like CNC-ported cylinder heads, titanium connecting rods and intake valves, and sodium-cooled exhaust valves. The engine is hand-assembled to race-engine standards at GM's Performance Build Center in Wixom, Michigan
Increasing intake airflow through a 90-mm throttle-body and big, straight-shot intake ports and freeing up the exhaust with hydroformed four-into-one headers and three-inch exhaust pipes also provide some added power. An electronically-controlled valve in each muffler opens when engine-speed tops 3500 rpm, creating a wonderfully guttural roar, but I have it on good authority that disconnecting just the right wire keeps those valves open all the time.
On the Road
If you are judicious with application of the right pedal, driving the Z06 is little different than driving any other C6. Almost everything inside is the same apart from a revised gauge cluster and the seats. They feature fixed side-bolsters to better hold the driver in place, and the passenger's seat forfeits power controls to save a little more weight. Features such as HID lighting, fog lamps, leather seating, dual-zone air-conditioning, and head-up display (HUD) with track mode and g-meter are all standard.
GM says the Z06's acoustic package is also revised to reduce weight and "allow more aural feedback from the powertrain." Smart move, for even at idle, the sound of that seven-litre V8 burbling away like some reincarnated Can-Am racer is immensely satisfying. So is its part-throttle response, providing enough instant thrust for any conceivable real-world driving need.
As a highway cruiser the Z06 is comfortably benign but in the twisties it fairly comes alive, turning in sharply with a fluid ease that belies its size. If there is any body roll it is simply not evident, and even the ride quality is superior to that of many 'wannabe' sporty cars.
When you get tired of playing nice and want to nail the throttle … well, that's when it's time to start looking for a drag-strip, or a solo race, or track that offers lapping sessions.
On the Track
It is only on a track that one can come close to appreciating the brilliance of the Z06, or truly test its capabilities. On the tighter elements of VIR it reached what seemed like impossible cornering loads before the Active Handling System gently intervened. Resetting it to competition mode lets one hang the car out even further before saying "enough."
To my surprise, the front tires hung on tenaciously, permitting mid-corner adjustments with judicious use of the right foot, and it flicked its way through VIR's multiple esses with go-kart ease, rather than lurching from point to point as in some high-performance cars.
When I put my foot down coming off the corners, it was like pulling the release lever on my own personal catapult. Explosive is the only way to describe this car's acceleration ability.
GM says it will do 0-to-100 km/h in 3.9 seconds - delayed by the need for an upshift from 1st to 2nd gear just before reaching that speed - and it will run the quarter-mile in 11.7 seconds at 125 mph (201 km/h). Top speed is said to be 198 mph (319 km/h). I can't verify that number, but I can vouch for the fact that it is still pulling strong at 160 mph (257 km/h).
As for braking, I consistently underestimated the car's ability, braking way earlier than needed. It took a ride with Corvette racer Johnny O'Connell to learn just how good the brakes really are - incredible - and how far away from the car's ultimate limits I really was. My self-preservation instincts had automatically intervened well before I approached the car's ultimate limits. It takes a driver of considerable talent to get everything it has out of a Z06.
Conclusion
The 2006 Z06 is truly a milestone car and not just in terms of the exceptional performance of which it is capable. Its real achievements are combining supercar performance with a level of civility that surpasses that of many far lesser vehicles, and doing so at the price of a mere luxury car.