Ken
Gone but not forgotten
From Popular Mechanics:
VIPER VS. VETTE
America's sports cars are road racing again
BY JIM MCCRAW
Just when we thought that participation in big-time road racing was kind of a dead issue in Detroit, along comes a seriously renewed interest on the part of not one but two automakers. The company formerly known as Chrysler had been supporting its Viper GTS with a real factory-backed purpose-built race program, the GTS-R. Now things will get some added spice this season and next thanks to the arrival of the officially supported Chevrolet Corvette C5-R.
How much are the Vette and Viper road racers alike and how much are they like the Vette or Viper you may see down at the local dealer? Read on.
Chevrolet debuted the new C5-R factory race car at last November's Specialty Equipment Manufacturer's Association (SEMA) Show in Las Vegas. The C5-R was designed and built to compete in FIA GT2 sprint and endurance races against the Porsche 911, BMW 3 Series and, of course, the Dodge Viper GTS-R–campaigned by professional factory teams. Still teething, the Corvette C5-R race car is a Pratt & Miller Racing design, built at the firm's shop in Wixom, Mich., near Detroit.
Pratt & Miller started 18 months ago with a completely stock C5 Corvette. They tore it down to its most basic components, and built it back up into a pure race car, slightly longer, lower and wider than a production C5. The stock C5's 104.5-in. wheelbase stretched to 104.7 in. The length was stretched from 179.7 in. to 182.8 in. overall. The C5's stock height of 47.8 in. was lowered to 45.8, and the car's width was stretched from the stock 73.6 in. to 76.4 in.
Canadian Trans-Am racer Ron Fellows is the lead driver, along with veteran road racers Chris Kneifel and John Paul Jr. A second team, from the Riley & Scott race shop in Indianapolis, also runs a C5-R with drivers Scott Sharp, Andy Pilgrim and GM engineer/racer John Heinricy.
The C5-R uses a specially built 6.0-liter small-block V8, with a 4.125-in. bore and a 3.42-in. stroke for a total of 365 cu. in. The stock Corvette's aluminum small-block engine has a 3.90-in. bore and 3.62-in. stroke, with 10.5:1 compression, making 345 hp, while the race engine's output is at least 600 hp at 7200 rpm with 495 ft.-lb. of torque at 5600 rpm.
The racing engine's block has larger water passages than a stock block. The reciprocating assembly is based on a Moldex billet crank, Carillo connecting rods and JE forged racing pistons. The cylinder heads have been altered extensively from stock, with 12.5:1 compression. The valvetrain uses a Competition Cams grind on a Chevrolet camshaft blank. Chevrolet chose Iskenderian lifters, Fox pushrods and Jesel 1.9:1 rocker arms to complete the valvetrain.
A Kinsler racing fuel-injection system, with elaborate cross-ram air horns and a composite airbox between the engine and the hood, breathes through an air intake behind the headlamps. An aluminum motor plate mounts to the front of the block, with a structural aluminum oil pan and a modified stock aluminum front subframe. The engine uses an external mechanical three-stage oil pump and dry-sump lubrication with the oil tank under the fuel tank.
A five-speed Hewland racing transmission replaces the standard six-speed, mounted ahead of the differential. The balance of the drivetrain includes a 5.5-in. triple-disc Tilton carbon clutch, and a Pratt & Miller 3.11:1 rear end with Metalore axles and CV joints.
The electronics package includes two Delphi Electronics engine computer-and-ignition systems and a complete Pi Research Systems 6 dashboard display, data acquisition and telemetry system that includes motion sensors on the front and rear suspensions.
The C5-R factory race car is based on the stock Corvette's hydroformed frame rails, stock front and rear aluminum subframes, stock front upper and lower control arms, and stock rear lower control arms. The standard rear upper control arms are new, fabricated by Pratt & Miller to clear the Alcon aluminum racing brakes.
Instead of fiberglass, the C5-R's body is carbon-fiber composite. And the C5-R weighs 2510 pounds rather than the stock car's 3245. A new air intake system for engine cooling has a scoop positioned above the deep front spoiler, and the body has lowered sills to house the 4-in. exhaust pipes. The roof has a forward-facing scoop for driver ventilation, and a NACA duct to the rear for the transmission and differential coolers. There's a three-element adjustable aluminum rear spoiler. The stock 19.1-gal. fuel tank was changed to a 26.4-gal. or 100-liter fuel cell for racing, with dual electric fuel pumps. A one-piece composite front end carries a Davis aluminum radiator and carbon-fiber ducting to exhaust hot air through hood louvers.
Where the stock Corvette has short- and long-arm front suspension with forged aluminum control arms, the race car has the same basic setup with forged upper and cast lower arms with a fabricated steel knuckle, triple-adjustable JRZ coil-over shock units (high- and low-speed jounce plus rebound) and an adjustable stabilizer bar. At the rear there are short and long arms with fabricated-steel upper and cast-aluminum lower arms, a fabricated steel knuckle assembly, three-way adjustable JRZ coil-over shock units and an adjustable rear stabilizer bar.
As for rubber, the race setup requires Goodyear Racing Eagle 25x19x18 front tires and 28x12.5x18 rear tires on BBS forged magnesium center-lock wheels. These are stopped by Alcon 15x1.38 front rotors and 14x1.26 rear rotors, yielding 635 sq. in. of braking area for the race car versus 421 for the street version, a 51 percent increase.
Dodge Viper GTS-R
Back in 1995, Chrysler introduced the Dodge Viper GTS-R, a limited-production racing car intended for FIA GT-class competition. The standard powertrain was a 525-hp 8.0-liter V10, with 650- or 750-hp engines available as optional equipment. It was designed to be a serious competition car for the world's greatest races, the 24 Hours of Daytona, the 12 Hours of Sebring and the 24 Hours of LeMans. The GTS-R was a factory-built race car for professional racing teams. The Viper GTS-R won the prestigious 1997 FIA GT2 championship and the 1998 24 Hours of LeMans in the GT2 Class. It was the first production-based car from an American manufacturer ever to win the French classic. GTS-R competes in international road racing in the same GT2 class as the Corvette C5-R, with a much larger engine and a much larger aerodynamic profile.
The Viper GTS-R came in first and second in class at the 24 Hours of LeMans in 1998 and won its class title two years in a row in the hands of the French ORECA team run by Hugues de Chaunac from his shop in southern France. ORECA drivers include Briton Justin Bell, Americans David Donohue and Tommy Archer, French driver Olivier Beretta, Italian Luca Drudi, Portuguese Pedro Lamy and Austrian Karl Wendlinger.
The GTS-R bodywork is carbon fiber like the Corvette's and the car weighs only 2650 pounds. It sports a huge standoff rear spoiler, side exhausts, a roof vent and two pairs of extra driving lamps built into the carbon-fiber nosepiece for night racing. The first GTS-Rs were designed and built at Chrysler headquarters in Auburn Hills, Mich., but all 1999 race cars and customer cars will be assembled at the ORECA shop in France from parts sent over from DaimlerChrysler's motorsports engineers.
The 8.0-liter V10 uses a forged crankshaft, Carillo rods and forged 12:1 pistons, all-new valvetrain parts for 7000-rpm running and speed-density electronic fuel injection with a Motec controller, Bosch racing injectors and stainless steel headers. Lubrication has been changed over from wet-sump to a four-stage Caldwell pump and dry-sump system with a 12-quart remote tank. It drives through a three-disc 7.25-in. Tilton racing clutch with a Borg-Warner six-speed transmission and a 9.75-in. Dana 60 aluminum rear end with racing halfshafts and CV joints.
The GTS-R is equipped very much like the Corvette, with a roll cage, a space frame and a flat bottom. The suspension uses stock aluminum wishbones with Dynamic coil-over shocks, R&S hubs and modified stock knuckles to mount larger bearings and the Brembo brakes, with a 57mm front stabilizer bar and an adjustable rear bar. The racing fuel cell holds 100 liters or 26.4 gal., restricted by class rules.
The GTS-R uses 12x18-in. front and 13x18-in. rear OZ center-lock alloy wheels and Michelin Pilot SX slicks with Brembo six-piston 15-in. carbon/metallic front brakes and four-piston 14-in. carbon/metallic rear brakes.
Eight customer cars will be built for 1999, two using the proven ORECA chassis from last year and six more brand new from the ground up. All eight are spoken for, at an average price of $325,000 each, ready to race.
VIPER VS. VETTE
America's sports cars are road racing again
BY JIM MCCRAW
VIPER GTS-R
Just when we thought that participation in big-time road racing was kind of a dead issue in Detroit, along comes a seriously renewed interest on the part of not one but two automakers. The company formerly known as Chrysler had been supporting its Viper GTS with a real factory-backed purpose-built race program, the GTS-R. Now things will get some added spice this season and next thanks to the arrival of the officially supported Chevrolet Corvette C5-R.
How much are the Vette and Viper road racers alike and how much are they like the Vette or Viper you may see down at the local dealer? Read on.
VETTE C5-R
Chevrolet debuted the new C5-R factory race car at last November's Specialty Equipment Manufacturer's Association (SEMA) Show in Las Vegas. The C5-R was designed and built to compete in FIA GT2 sprint and endurance races against the Porsche 911, BMW 3 Series and, of course, the Dodge Viper GTS-R–campaigned by professional factory teams. Still teething, the Corvette C5-R race car is a Pratt & Miller Racing design, built at the firm's shop in Wixom, Mich., near Detroit.
Pratt & Miller started 18 months ago with a completely stock C5 Corvette. They tore it down to its most basic components, and built it back up into a pure race car, slightly longer, lower and wider than a production C5. The stock C5's 104.5-in. wheelbase stretched to 104.7 in. The length was stretched from 179.7 in. to 182.8 in. overall. The C5's stock height of 47.8 in. was lowered to 45.8, and the car's width was stretched from the stock 73.6 in. to 76.4 in.
Canadian Trans-Am racer Ron Fellows is the lead driver, along with veteran road racers Chris Kneifel and John Paul Jr. A second team, from the Riley & Scott race shop in Indianapolis, also runs a C5-R with drivers Scott Sharp, Andy Pilgrim and GM engineer/racer John Heinricy.
The C5-R uses a specially built 6.0-liter small-block V8, with a 4.125-in. bore and a 3.42-in. stroke for a total of 365 cu. in. The stock Corvette's aluminum small-block engine has a 3.90-in. bore and 3.62-in. stroke, with 10.5:1 compression, making 345 hp, while the race engine's output is at least 600 hp at 7200 rpm with 495 ft.-lb. of torque at 5600 rpm.
The racing engine's block has larger water passages than a stock block. The reciprocating assembly is based on a Moldex billet crank, Carillo connecting rods and JE forged racing pistons. The cylinder heads have been altered extensively from stock, with 12.5:1 compression. The valvetrain uses a Competition Cams grind on a Chevrolet camshaft blank. Chevrolet chose Iskenderian lifters, Fox pushrods and Jesel 1.9:1 rocker arms to complete the valvetrain.
A Kinsler racing fuel-injection system, with elaborate cross-ram air horns and a composite airbox between the engine and the hood, breathes through an air intake behind the headlamps. An aluminum motor plate mounts to the front of the block, with a structural aluminum oil pan and a modified stock aluminum front subframe. The engine uses an external mechanical three-stage oil pump and dry-sump lubrication with the oil tank under the fuel tank.
A five-speed Hewland racing transmission replaces the standard six-speed, mounted ahead of the differential. The balance of the drivetrain includes a 5.5-in. triple-disc Tilton carbon clutch, and a Pratt & Miller 3.11:1 rear end with Metalore axles and CV joints.
The electronics package includes two Delphi Electronics engine computer-and-ignition systems and a complete Pi Research Systems 6 dashboard display, data acquisition and telemetry system that includes motion sensors on the front and rear suspensions.
The C5-R factory race car is based on the stock Corvette's hydroformed frame rails, stock front and rear aluminum subframes, stock front upper and lower control arms, and stock rear lower control arms. The standard rear upper control arms are new, fabricated by Pratt & Miller to clear the Alcon aluminum racing brakes.
Instead of fiberglass, the C5-R's body is carbon-fiber composite. And the C5-R weighs 2510 pounds rather than the stock car's 3245. A new air intake system for engine cooling has a scoop positioned above the deep front spoiler, and the body has lowered sills to house the 4-in. exhaust pipes. The roof has a forward-facing scoop for driver ventilation, and a NACA duct to the rear for the transmission and differential coolers. There's a three-element adjustable aluminum rear spoiler. The stock 19.1-gal. fuel tank was changed to a 26.4-gal. or 100-liter fuel cell for racing, with dual electric fuel pumps. A one-piece composite front end carries a Davis aluminum radiator and carbon-fiber ducting to exhaust hot air through hood louvers.
Where the stock Corvette has short- and long-arm front suspension with forged aluminum control arms, the race car has the same basic setup with forged upper and cast lower arms with a fabricated steel knuckle, triple-adjustable JRZ coil-over shock units (high- and low-speed jounce plus rebound) and an adjustable stabilizer bar. At the rear there are short and long arms with fabricated-steel upper and cast-aluminum lower arms, a fabricated steel knuckle assembly, three-way adjustable JRZ coil-over shock units and an adjustable rear stabilizer bar.
As for rubber, the race setup requires Goodyear Racing Eagle 25x19x18 front tires and 28x12.5x18 rear tires on BBS forged magnesium center-lock wheels. These are stopped by Alcon 15x1.38 front rotors and 14x1.26 rear rotors, yielding 635 sq. in. of braking area for the race car versus 421 for the street version, a 51 percent increase.
Dodge Viper GTS-R
Back in 1995, Chrysler introduced the Dodge Viper GTS-R, a limited-production racing car intended for FIA GT-class competition. The standard powertrain was a 525-hp 8.0-liter V10, with 650- or 750-hp engines available as optional equipment. It was designed to be a serious competition car for the world's greatest races, the 24 Hours of Daytona, the 12 Hours of Sebring and the 24 Hours of LeMans. The GTS-R was a factory-built race car for professional racing teams. The Viper GTS-R won the prestigious 1997 FIA GT2 championship and the 1998 24 Hours of LeMans in the GT2 Class. It was the first production-based car from an American manufacturer ever to win the French classic. GTS-R competes in international road racing in the same GT2 class as the Corvette C5-R, with a much larger engine and a much larger aerodynamic profile.
The Viper GTS-R came in first and second in class at the 24 Hours of LeMans in 1998 and won its class title two years in a row in the hands of the French ORECA team run by Hugues de Chaunac from his shop in southern France. ORECA drivers include Briton Justin Bell, Americans David Donohue and Tommy Archer, French driver Olivier Beretta, Italian Luca Drudi, Portuguese Pedro Lamy and Austrian Karl Wendlinger.
The GTS-R bodywork is carbon fiber like the Corvette's and the car weighs only 2650 pounds. It sports a huge standoff rear spoiler, side exhausts, a roof vent and two pairs of extra driving lamps built into the carbon-fiber nosepiece for night racing. The first GTS-Rs were designed and built at Chrysler headquarters in Auburn Hills, Mich., but all 1999 race cars and customer cars will be assembled at the ORECA shop in France from parts sent over from DaimlerChrysler's motorsports engineers.
The 8.0-liter V10 uses a forged crankshaft, Carillo rods and forged 12:1 pistons, all-new valvetrain parts for 7000-rpm running and speed-density electronic fuel injection with a Motec controller, Bosch racing injectors and stainless steel headers. Lubrication has been changed over from wet-sump to a four-stage Caldwell pump and dry-sump system with a 12-quart remote tank. It drives through a three-disc 7.25-in. Tilton racing clutch with a Borg-Warner six-speed transmission and a 9.75-in. Dana 60 aluminum rear end with racing halfshafts and CV joints.
The GTS-R is equipped very much like the Corvette, with a roll cage, a space frame and a flat bottom. The suspension uses stock aluminum wishbones with Dynamic coil-over shocks, R&S hubs and modified stock knuckles to mount larger bearings and the Brembo brakes, with a 57mm front stabilizer bar and an adjustable rear bar. The racing fuel cell holds 100 liters or 26.4 gal., restricted by class rules.
The GTS-R uses 12x18-in. front and 13x18-in. rear OZ center-lock alloy wheels and Michelin Pilot SX slicks with Brembo six-piston 15-in. carbon/metallic front brakes and four-piston 14-in. carbon/metallic rear brakes.
Eight customer cars will be built for 1999, two using the proven ORECA chassis from last year and six more brand new from the ground up. All eight are spoken for, at an average price of $325,000 each, ready to race.
