Aerodynamics played a big role in bringing in design changes to the all-new 2014 GMC Sierra full-size pickup truck, making it more fuel efficient and giving it a more silent cabin. It turned out that the 2014 Sierra had more development time in a wind tunnel than any GMC pickup before it. Aerodynamic engineers like Diane Bloch examined every square inch of the Sierra to spot areas that needs to be improved while demystifying some myths along the way.
They used General Motors’ advanced Aerodynamics Lab, a 750-foot-long tunnel in which flow winds of up to 138 mph as produced by 43-foot-diameter fan powered by a 4,500-hp DC electric motor. The Lab allowed engineers to study the way air passes over, under and around the 2014 Sierra. Advancement in aerodynamics will allow the 2014 Sierra to become the most fuel-efficient V-8 pickup.
For instance, a new air dam below the front bumper reduces drag by directing air toward the ground, away from the 2014 Sierra’s underbody. The ducted flow path between the Sierra’s grille and radiator prevents air from moving around inside the truck’s front cavities.
The top of the truck’s tailgate and the center high-mounted stop light are also optimized to guide air smoothly around the truck. During tests, engineers detected unwanted airflow between the cab and bed, and they resolved this issue by adding a new sealing.
Bloch remarked that they discovered that the most “harmful air” between the cab and bed came over the cab and down through the gap, making them pay more to this specific area. According to Block, aftermarket accessories for pickups have varying impact on aerodynamics. She said that accessories like bug deflectors on the hood, wider tires or aftermarket bumpers can increase the drag coefficient.