DETROIT – When the ’14 Chevrolet Corvette Stingray arrives at U.S. dealerships later this year, it will serve as a true halo car, helpingimprove the performance, safety and, ironically, fuel economy of future mainstream cars and trucks.
“As we go forward in the new regulatory environment, we will learn a ton from this car,” GM North American President Mark Reuss tells WardsAuto in an interview here.
Light-vehicle fleets must achieve 35.5 mpg (6.6 L/100 km) by 2016, the biggest industry-mandated efficiency leap since the introduction of U.S. corporate average fuel economy rules in 1975. By 2025, the bogey could climb to 54.5 mpg (4.3 L/100 km), costing car companies an estimated $160 billion in fuel-saving technology investments.
A key step for GM in that direction is the new high-powered Corvette that boasts an all-new powertrain that strikes a balance between performance and efficiency.
Despite an impressive minimum output of 450 hp and 450 lb.-ft. (510 Nm) of torque, the seventh-generation standard-model Corvette will surpass 26 mpg (9 L/100 km) when test results from the U.S. Environmental Protection Agency come later this year, GM engineers promise.
The Corvette’s all-new, fifth-generation small-block V-8 ushers to market a number of fuel-saving technologies. Some, such as gasoline direct injection, continuously variable valve timing and cylinder deactivation, are not new to GM vehicles but are taken to new levels with the Corvette.
Others, such as advanced lightweight materials, are used more broadly or come to production on a standard vehicle for the first time.
The new small-block debuts with one of the industry’s most-advanced combustion systems. Research on the system used up more than 6 million of the 10 million hours of the engine’s computational analysis. It also took two of the program’s five years of development and radically changed the size and placement of key engine parts.
The engine’s technologies will appear on the next-generation GM fullsize trucks coming in late 2012 and 2013, as well future sports cars. Altogether, the new small-block engine family required an investment of $890 million.
Additional items Reuss sees trickling down from the Corvette into future volume products include an “extraordinary” rev-matching feature of the Corvette’s 7-speed manual transmission and a brake system he considers “quite sophisticated.”
A driver-selectable feature, rev-matching anticipates the next upshift or downshift and electronically “blips” the throttle for a seamless gear transition. It enhances the performance-driving aspect of the car but also saves fuel with smooth, timely shifts.
The seventh gear of the transmission saves dollars at the pump by acting as a “loafer gear” on the highway to boost efficiency.
The Corvette’s standard Brembo brakes were specially developed for the car. In addition to improving stopping power, they create less drag, which means less falloff in the car’s fuel economy and longer pad life.
“You are also going to see some really sophisticated chassis-control systems come out of this car and into others,” Reuss says of the Stingray. The more sophisticated the chassis controls, the more stable and safer a vehicle becomes.
The new Corvette also marks an aggressive advanced-lightweight-materials play for GM. For example, the car’s hood and removable roof panel are made of carbon fiber. It is the first time the material appears on a standard-model vehicle from GM, and the Stingray will be the largest-production-volume vehicle in the industry to use carbon-fiber panels.
“You could literally pick up the hood with two fingers,” Reuss says, noting GM will learn much about the mass-production of carbon fiber, including how to paint the parts and properly bolt them to the car during the assembly process.
“We’re ahead of everybody, frankly, with some of the (carbon-fiber) hoods and pieces we’ve done on Corvettes prior to this one. And now we’re bringing it into the mainline standard Corvette. It’s exciting.”
Corvette also employs a carbon-nano-composite technology for lighter underbody panels without losing strength or stiffness. The technology blends traditional composite materials and carbon fiber.
The Stingray’s fenders, doors, rear-quarter panels and rear-hatch panel use a lighter-density sheet-molded compound than the previous generation. The materials combine to save an estimated 37 lbs. (17 kg) compared with the previous body structure.
The Stingray’s all-new aluminum frame structure is 57% stiffer and 99 lbs. (45 kg) lighter that of previous models. It employs an alternative approach to frame-rail assembly, stepping away from the longtime hydroforming method that gave the rails a constant 0.78-in. (2-mm) thickness.
Now the rails are composed of five customized aluminum segments with thicknesses ranging from 0.78-0.43 in. (11 mm). The gauge, shape and strength of each segment are tuned to optimize the requirement of each section to save weight.
GM will build the frame in-house for the first time at the Corvette’s Bowling Green, KY, assembly plant. The facility underwent a $131 million upgrade to accommodate the new Stingray, including $52 million for the body shop for construction of the frame.
The auto maker uses innovative ways to cut weight from the Corvette’s chassis as well. The rear suspension’s lower control arms are hollow, shaving 9 lbs. (4 kg), and new aluminum rear toe links are 2.4 lbs. (1.9 kg) lighter than their steel predecessors. The front-suspension arms are hollow-cast aluminum, rather than solid aluminum.
The new model also rates as the most aerodynamic Corvette ever, with elements such as a new grille and radiator arrangement and hood vents contributing to a more slippery and fuel-efficient design. New side coves in the front fenders also reduce drag.
The hood vents, which enhance stability, may not appear on many mainstream GM vehicles, but future cars could begin mimicking the shape of the Corvette to gain aero.
The Corvette for the first time applies GM’s new shape-memory alloy for the active rear- hatch vent of the Stingray. The auto maker believes it is the industry’s first use of the material.
Shape-memory alloys bend and straighten through the application of an electric current, allowing GM to replace a heavier electric motor for the active rear-hatch vents with a simple spring.
It saves about 1.0 lb. (0.5 kg) on the Corvette. However, in the future it could be applied to more of the electric motors on a vehicle, which can number more than 200 on some models, making for considerable weight savings.
As much as the new Corvette might raise the performance, safety and fuel efficiency of future GM cars and trucks, it also will lift the spirits of a company that has taken its share of negative news over the past several years, Reuss says. “The whole political arena changed radically over the last few years as we went through bankruptcy, and a lot of people really needed something to believe in.
“This car is one of those things,” he says, recalling a sneak preview of the Stingray to employees ahead of its debut at the recent North American International Auto Show. The preview drew a pair of standing ovations.
“That’s the way we feel about it,” Reuss says. “This business is supposed to fun, right? This is fun. This car is why I joined the company.”