Wednesday, May 22, 2013

Chevrolet Corvette C6 ZR1


The Chevrolet Corvette C6 ZR1 is a high performance version of the Chevrolet Corvette C6. Both the C3 from 1969–1971 and C4 Corvettes from 1990-1995 also had ZR-1 models.





This is the extreme version of the already bonkers Corvette Z06. Though that one has a giant 7 liter, the ZR1 makes do with a 6.1 liter number. But make no mistake, this one is a supercharged unit. Designated the LS9, it produces a maximum of 638 bhp of power, making this model of the Corvette the most powerful ever in its entire history. 



It provides Ferrari F12 like straight line performance, for less than half its price. For its price, it competes with the Ferrari 458 Italia, McLaren MP4-12C, Lamborghini Gallardo, Audi R8 and the Dodge Viper.   





Components

Engine design

The Corvette ZR1 engine is a heavily modified version of the LS3 Corvette engine, designated the supercharged LS9 Corvette engine. Producing 638 hp (476 kW; 647 PS) and 604 lbf·ft (819 N·m) of torque, it is the most powerful production Corvette to date. The LS9 has a sixth-generation Eaton TVS R2300 roots 4-lobe supercharger with intercoolers from Behr, utilizing an air-to-water, dual-brick design. The superchargers four-lobe design offers improved efficiency over three-lobe models. To avoid changes to the hood appearance, the superchargers output was split into two halves. Each cylinder bank has an intercooler.

The cylinder walls of the LS3 are thicker than the Z06s LS7 since the LS3 has a smaller bore. Oil squirters under each piston help cool the pistons. Connecting rods and the inlet valve are made of titanium. Heads are made from a special heat resistant aluminum alloy. The camshaft lift was reduced from the LS7s to improve idle quality. With the addition of the supercharger to the 6.2 liter LS9, the higher lift camshaft was no longer necessary to achieve horsepower targets.


Lubrication is provided by an improved version of the LS7s dry sump system. The new system increases oil capacity from 8.0 to 10.5 quarts (9.94 liters). A new dual gerotor oil pump increases scavenge performance and oil pressure, enabling oil to be delivered under the most extreme conditions. The LS7 oilpan is used for the LS9 with the addition of an oil cooler which is mounted on the left side of the pan.
With the 2011 model, GM offers the optional "Corvette Engine Build Experience," where the customer visits the General Motors’ Performance Build Center to help assemble the LS9 for the ZR1 purchased. Factory technicians supervise the process and the normal warranty covers the engine built by the customers hands.




Transmission

The ZR1 flywheel has been improved over the 2008 Z06. The flywheel was upgraded by going from six to a 9 bolt design and cutting off nearly 9.8 ounces (278 grams) for improved throttle response and acceleration.


The ZR1 has a 6-speed manual Tremec TR-6060 transmission with a MH3 gearset, while the 2008 Z06 featured the MM6 gearset.

Differential/drive

The differential is a limited slip with carbon and steel plates. The differential uses SAE 5W-80 Dexron LS lubricant.
The two half shafts have different diameters (33mm left, 40mm right), designed to prevent resonance during acceleration and reduce the chances of wheel hop.

Production








Production vehicles are hand assembled in Bowling Green, Kentucky. The ZR1 engines are built at the General Motor Performance Build Center in Wixom, Michigan.

Ride control

The name of the ride control system is Magnetic Selective Ride Control (MSRC). MSRC is provided by Delphi Automotive Systems from technology invented by the GM Research Laboratories. The system uses two modes of control: Tour and Sport.
The system offers standing start launch modifications. When launching the ZR1 from a standing start, the shocks are completely softened on launch and stiffened on rebound. The softened shocks on launch aid the ZR1 by allowing weight to transfer to the rear, aiding traction. The ride control standing launch modifications are designed to minimize bounce.

Suspension

The ZR1 features a double-wishbone suspension system and Magnetic Selective Ride Control—which adjusts shock-absorber damping in real time to either "Tour" or "Sport" mode.
The MSRC shocks are automatically adjusted based on driving conditions and vehicle dynamics (cornering, braking, etc) for optimal handling. The system is adjusted every millisecond to provide sharp handling during spirited driving, and a smooth ride while cruising.
The new high-end magnetic suspension system enables the ZR1 to deliver great handling and grip to achieve 1.10 g of average lateral acceleration.

Chassis/body


Right rear 3/4 view of Corvette ZR1
The chassis, similar to the 2008 Z06, is made of aluminum. To cut weight, many panels are made of carbon fiber. Panels made of carbon fiber are the fenders, hood, roof, splitter, and rocker extensions. To prevent the sun from damaging the binder in the exposed carbon fiber composite body panels, panels are protected with a clear coating.
The rear wheels are the largest ever mounted on a production Corvette with 335/25 Michelin Pilot Sport PS2 tires on 20 in (510 mm) wheels.
The ZR1 has a length of 176.2 inches (4,480 mm), width of 75.9 inches (1,930 mm), and height of 48.7 inches (1,240 mm). The ZR1 has a curb weight of 3,405 lb (1,544 kg).

Clutch

The 260 mm (10 in) ZF-Sachs twin-plate clutch supplants Z06s 290 mm (11 in) single-plate unit to reduce inertia for better shift feel. The lower clamping force reduces clutch-pedal effort. The clutch upgrade is considered a dramatic improvement over the unit employed within the Z06.

Brakes

The front brake rotors are similar to the carbon ceramic design employed in the Ferrari FXX track car, the difference being a diameter reduction from 15.75 in (400 mm) to 15.5 in (390 mm) for added wheel clearance. The front calipers are Brembo 6-piston units.

Rear calipers are Brembo 4-piston units. The rear brakes are 15 in (380 mm) carbon ceramic rotors, originally employed as the Enzo Ferraris front rotors. Same as those used in the BMW M3 GTS.
Both front and rear pads have twice the contact area of the Z06s, as well as the addition of brake pad wear sensors. The brake master cylinder, booster, ABS unit and system controller are now obtained from Bosch instead of Delphi.


As a result, the ZR1 will stop from 60 mph (97 km/h) in a current production car record-breaking 96 feet (29.3 m).

Ignition

Coil packs are identical to those used on the LS3. The coil packs are mounted on the valve covers.

Fuel system

A unique fuel pressure regulator varies pressure between 36.3 and 87.0 psi (250 and 600 kPa) depending on rpm.

Identification


Hood window of ZR1
The ZR1 features blue badges, engine valve covers, and brake calipers. The hood contains a polycarbonate window which allows the intercooler to be viewable. Doors and rear body are from the 2008 Z06. A spoiler which is larger than those on the previous models spans the top rear bumper. Functional fender vents provide engine cooling. The lettering "LS9 Supercharged" can be viewed on top of the plastic supercharger cover through the hood window.

Specifications

Estimated
  • Displacement: V8 6.162 L (376.0 cu in) w/ (Eaton) TVS Supercharger & Intercooler.
  • Horsepower: 638 bhp (476 kW; 647 PS) at 6500 rpm 
  • Torque: 604 lbf·ft (819 N·m) at 3800 rpm 
  • Bore: 103.25 mm (4.065 in)
  • Stroke: 92.0 mm (3.62 in)
  • Compression: 9.1:1
  • Supercharger maximum boost: 10.5 psi (0.7 bar)
  • Redline: 6500 rpm 
  • Clutch: 260 mm (10 in)
  • Final Drive Ratio: 3.42:1
  • 1st gear ratio: 2.29
  • 1st gear top speed: 106 km/h (66 mph)
  • 2nd gear top speed: 155 km/h (96 mph)
  • 3rd gear top speed: 210 km/h (130 mph)
  • 6th gear ratio: 0.67
  • Wheel size front: 19 in (480 mm) diameter by 10 in (250 mm) width
  • Wheel size rear: 20 in (510 mm) diameter by 12 in (300 mm) width
  • Tire size front: 285/30R-19
  • Tire size rear: 335/25R-20
  • Brakes front: Brembo 15.5 in (390 mm)
  • Brakes rear: Brembo 15.0 in (380 mm)
  • Front/rear balance: 52/48
  • Curb Weight: 3,324 lb (1,508 kg)
  • 0-60 mph (97 km/h): 3.3
  • Top speed: 205 mph (330 km/h)
  • Quarter mile (~400 m) time: 11.2
  • Quarter mile speed: est. 130 mph (210 km/h)
  • Production: 2000 units per year (estimated)
  • Price: US$111,525 to US$129,945
  • Lateral acceleration: 1.10 g (average) 

Awards and recognition



  • 2009 Performance Car of the Year, Top Gear
  • Best New Cars of 2009, About.com Cars
  • Automotive Journalist and Top Gear presenter Jeremy Clarksons Car of the Year Award.
  • Achieved a Nordschleife lap time of 7 minutes and 26.4 seconds making it one of the fastest production cars to lap the circuit. / Inc., Quarter Mile time of 10.89 Sec..
  • The 2012 Chevrolet Corvette C6 ZR1 was tested at the Nurburgring by Jim Mero on June 9, 2011. It was a base specification car with optional super-slick DOT track competition tires (Michelin Pilot Sport Cup Zero Pressure) and non-stock safety equipment. It recorded a time of 7:19.63 (Video confirmed), the 5th-best time ever for a production vehicle.
  • Achieved the fastest recorded speed for a production car on the Bonneville Salt Flats of 176.54 mph (284.11 km/h) driven by Jeremy Clarkson of the BBC TV Show Top Gear.





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