Doing so required not only developing an aero-optimized grille and air dam, but also a removable center section for the Z51 performance option, to provide better stability at high rates of speed. Bednarchik points out that while shapes for improving fuel efficiency typically begin to have an effect at highway speeds, lift and drag components become critical from 150 mph to maximum velocity.
In addition, as mentioned previously, the previous configuration of “bottom breather” airflow to the radiator didn’t work all that well at speeds that Corvettes are now seeing on racetracks. The change to a forward-angled radiator would be the first of many refinements forged in the heat of competition. In this configuration, air is force-fed into the engine bay and then ducted out over the top of the hood, an arrangement that provides more inherent downforce. About half the air goes over the top, with less than half spilling out through the side vents.
 Every surface of the Stingray was analyzed for airflow, including the vents in the si
Even the shaping of the air duct in the hood makes a difference. Rather than being merely an added-on aesthetic element, the extractor’s vanes are angled to manage airflow, minimizing the separation of the air from the body.
The CFD and wind-tunnel analyses led to other subtle features that streamlined the shape, “to make sure the airflow sticks to the body,” Bednarchik says. If it doesn’t, turbulence and wind resistance can develop, increasing the coefficient of drag. For an aerodynamic engineer, that’s the enemy.
Yet minimizing this aspect required tempering by certain legacy styling cues. For example, the design team determined early on that retro-inspired side coves would be an important element of the new body. Since the shape of the early coves created some turbulence, Bennion and Bednarchik took pains to ensure that the C7’s modernized treatment did, in fact, relieve underhood pressure and thus lower the car’s Cd.
But it doesn’t stop there. When we offhandedly inquired about what went into the shaping of the side mirrors, Bednarchik enthusiastically responded, “I’m really glad you asked about them!” Clearly we had touched a nerve for him on a subject that casual observers wouldn’t normally give a second thought.
It turns out that nearly 20 different mirror configurations were considered and tested in the wind tunnel, leading to the discovery of that millimeter of difference mentioned at the outset. “You can’t just put mirrors on from another car and expect the airflow to work the same,” Bednarchik explains. “Their wake affected airflow to the [auxiliary] coolers and Z51 spoiler. You have to look at it as a system. You can’t develop a mirror on one car and transfer it to another.”
 While the ducts in the rear quarters might look inconsequential, an extraordinary amo
Why so much time spent on such seemingly simple elements? Bednarchik admits that aerodynamics at times is a “black art, trial and error at times.” So, surprisingly enough, yarn tufts are still found in the designer’s toolbox (to evaluate the smoothness of large body panels), along with another telltale: ink drops. These were applied numerous times on the Stingray’s mirrors, so much so that the side of the test car was completely stained after 20 sessions in wind tunnel, visibly displaying the air paths and possible disruptions in flow.
Another area required even more experimentation. “We spent a lot of time with the CFD in designing the rear aux coolers,” Bednarchik notes. Again emulating the work done by the race team, designers configured the bodywork so that air enters the tops of the quarter panels, flows to the coolers housed in the lower outboard corners (trans on driver side, differential on the passenger’s), and exits at the rear fascia.
“We learned a lot from them, in aligning the vanes and the grille’s spider-weave mesh. Certain configurations would either choke or improve airflow.” All told, these rear cooling ducts alone required 100 different iterations evaluated over a year’s time.
Why was this element so critical? Because the ducting had to be “…not just functional but optimal,” Bennion notes. “In feeding the right amount of air—eight cubic meters per minute—each vane has its own particular location and shape. We don’t have a car unless we get all the airflow into it.”
Stepping back and considering the airflow dynamics as a whole, “The big takeaway is that the Stingray is great looking, but every aspect is aerodynamic, with low drag and enhanced lift,” Bednarchik concludes. (We’ve reviewed some preliminary figures, but final numbers were not available as we went to press.)
Suffice it to say that every smidgen of slipperiness is like free horsepower, giving the car an edge over its competition. And less lift means superior road-holding at high speed. All the CFD work in the wind tunnel paid off, as the lift numbers on a box-stock C7 are lower than on the aero-optimized C6 ZR1.
And while a wind-cheating shape is just one weapon in the C7’s formidable performance arsenal, it works in concert with the brawnier powertrain, stiffer structure, and other tangible enhancements to yield what is sure to prove the best-driving Corvette to date. Says Bednarchik, “The feedback from the ride-and- handling guys is that the ZR1 is faster…but the Z51 Stingray is better.”