Twenty-four hours a day and five days a week or more, the General Motors Aero Lab bustles with the business of aerodynamics testing, cooling optimization, and wind-noise reduction for current and future models. "The Aero Lab wind tunnel simulates a vehicle moving through the air by moving air past a stationary, instrumented vehicle," GM North America Lead Design Engineer Thomas Froling tells VETTE. "It is used most often to measure and optimize aerodynamic forces (especially drag), wind noise, and the airflow through the radiator and condenser (for engine cooling and air conditioning). Construction began in 1977, and the first tests were in August 1980."
"The GM Aero Lab is an amazing place," GM Performance Parts Manager Dr. Jamie Meyer says. "Tom's group is critical in the successful development of all of our production cars, but they really like to turn on the speed when they deal with high-performance cars like the Corvette. You have to remember that the work this team does has an immediate, positive impact on how a new vehicle performs. You are talking about decreasing drag to the point that it's equal to horsepowerùa lot of horsepower. Fuel efficiency obviously follows."
The Aero Lab is more than the General's in-house, high-tech playground for staff aerodynamics engineers. It's also the place where Bow Tie-loyal private race teams have the chance to gain a competitive edge over their opponents. "NASCAR and other teams have been conducting tests in GMAL for over 30 years," Froling explains. "If we charge an outside entity, the cost would be almost $2,000 per hour."
That's great news for Corvette race car teams like Late Model Racecraft, a Corvette- and LS-engine speed specialist in Houston, Texas, that campaigns an '08 "Voodoo Blue" Z06 in the Texas Mile. The car has earned the reputation as the World's Fastest Corvette, thanks to major deviations from stock, including a 440ci aftermarket block; modified LS7 cylinder heads; a custom, turbo-spec solid- roller camshaft; an LMR rear-mount twin- turbo; a TR-6060 six-speed manual trans with GForce 1-6 gearset; a custom quad- disc clutch; and a stock rearend from an '08 automatic-equipped base Corvette with a factory 2.56 gearset. It has aerodynamic upgrades, too, including a ZR1 front splitter and side skirts, and a custom carbon-fiber rear spoiler. It dynos at 1,600 rwhp and 1,480 rwtq.
"This was the first time we brought back a customer's production C6 into GMAL," Froling says.
Vehicle-aerodynamics testing is typically a two-day process. On July 21, 2011, GMAL technicians thoroughly cleaned the Corvette's exterior with a high-pressure car wash. "We don't do this to make [it] prettier," Froling smiles. "Our goal is to keep the lab's test section as clean as possible. Even small contaminants on a vehicle's exterior can affect its aero performance. Worse, they could cause wear to the testing equipment."
Then GMAL techs drove the Corvette onto a balance and weighed the vehicle at all four corners. Next, they meticulously measured the car's exterior dimensions and fed the data into GMAL's computer software.
The following day, the car was transferred to the lab's test section and put through a series of runs. "The equipment recorded a 0.373 drag coefficient and a +.023 CL lift baseline," Steven Fereday, the owner of LMR Racecraft, recalls.
After eight hours of testing and modifications, LMR had decreased the Corvette's drag coefficient to 0.307, and improved lift to CL = -0.030. According to Froling, the horsepower required to overcome the aero load, based on the car traveling at 150 mph, was reduced from 192.4 to 158.3.
LMR's hope was to increase the car's terminal velocity from 231 mph to 250 mph. GM's aerodynamics engineers concluded that their ministrations will speed LMR Racecraft's Corvette toward its goals.
Take a look at the accompanying photos from test day and see how it was done.
Based upon the data collected during its test session at the GM Aero Lab, Late Model Racecraft is now working on fiberglass and carbon-fiber production versions of a front splitter, side skirts, and rear spoiler, which it will offer to the public.
"To get these improvements with such minor changes to the vehicle is astounding," Fereday says. "With GM Performance Parts and GM Aero Lab's help, we'll be able to make the world's fastest Corvette even faster. Our goal now is to achieve 250 mph at our next speed run."
That will occur at the semi-annual Texas Mile, to be held at Chase Field Industrial Complex in Beeville, Texas, on October 21-23. For updates on LMR's Texas Mile C6 and its most-current speed-run results, visit the company's official website at www.latemodelracecraft.com.