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New Corvette Products from the 2014 SEMA Show

Flow-Down Lowdown: Getting the “Flow-Down” on GM’s Concepts for New Stingray Performance Parts

Steve Temple Apr 8, 2015
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The term “flow-down” refers to an engineering process described to us by GM’s Director of Performance Variants, Parts & Motorsports Engineering Mark Dickens. That’s quite a title, but he’s involved with quite a bit in the refinement of Corvette performance. Basically, in keeping with those familiar phrases noted above, what it means is that the parts developed for the higher-caliber Z06 result in a form of trickle-down economics, so owners of base-model Corvettes can enhance them. Nothing’s cast in stone yet with the concepts shown at the 2014 SEMA Show, but past programs have made concepts for performance parts available in relatively short order.

For instance, Dickens points out that the Z/28 Camaro went through a similar process last year. Of those items displayed as concept parts at the 2013 SEMA Show, 90 percent are now available for purchase. “Based on our track record on the Z/28, we might expect to see something that quickly again,” he allows.

What’s the motive behind this flow-down process? As good as the new Stingray is right out of the box, when it comes to Corvettes, there’s this relentless pursuit of excellence. Nothing less than optimum will do when it comes to GM’s performance flagship. (After all, nobody remembers who came in Second place on the track.)

To that end, key areas of the car—brakes, cooling, driveline, suspension, body components, and more—get additional attention, with minute enhancements measured right down to grams, millimeters, and percentage points.

Z06 Drive Shaft Couplers 2/8

The Z06’s carbon-fiber torque tube is 6 kg lighter than the base/Z51 steel unit, but provides the same level of torsional stiffness. The Z06’s driveshaft couplers (left), have a higher resistance to exhaust heat than the base Z51 couplers, for better durability on the track. Shown underneath the driveshaft are carbon-fiber underbody braces. Developed for use on the Z06, they offer a 17 percent weight reduction over the stock aluminum braces, yet with the same torsional stiffness. “Every ounce counts,” Dickens says.

Z06 Front Brake Duct Cooling Kit 3/8

As any physics student already knows, brakes work by converting kinetic motion into heat energy. But that means you need to expel excess heat to prevent brake fade. The available Z06/Z51 Front Brake Duct Cooling kit includes brake ducts and deflectors that transport air from the front grille through the wheelwells to more effectively cool the pads and rotors.

Z06 Front Grille 4/8

Designed to maximize airflow to the radiator, intercooler, and brake cooling ducts, the Z06’s front grille resulted in an airflow increase of 17 percent when compared with the Z51. In addition, the inlet ramps to the brake cooling ducts were optimized to balance the airflow demands of brake and engine cooling.

But Dickens is almost nonchalant about the effort involved. “We take the mystery out of speed,” he notes with the self-assurance typical of experienced engineers. “It’s an integrated package, developed by the same team of people [who developed the car] with all the engineering resources at their disposal.”

In other words, this team can employ GM’s massive computer power of CFD (computational fluid dynamics), wind-tunnel testing, simulations, and other track-testing technologies. Real-world, number-crunching science, not just vague intuition, comes to bear here. Not only that, “We save ourselves a thousand sets of tires by running simulations on a computer,” Dickens quips.

Wind-tunnel testing in particular played a significant role in the Stingray’s development, in order to evaluate the aerodynamics and airflow ducts. Computer analysis determined if each early design proposal hit the aero target. Commenting on this preliminary work studying the CFD, GM’s Exterior Design Manager Kirk Bennion points out that, “It’s a huge enabler, and there’s a big learning bandwidth.”

Specifically, computer-generated, meshed models and digital “ribbons” visually display the path of a single particle as it travels through and around the body. And this powerful analytic tool provides data on dozens of parameters, such as heat, velocity, and pressure coefficients, among many others, allowing for an unprecedented level of precision.

So what’s the benefit for the end user? “We take the Z51 ride and handling traits and shift the balance to handling,” Dickens adds. We can hardly wait to test out these parts, and experience the before-and-after effects firsthand. In the meantime, the accompanying photos and captions provide an insider glimpse into the future of Corvette performance.

Corvette Z06 Suspension Concepts 5/8

This concept suspension package was developed to improve the on-track handling capabilities of the Corvette Stingray. It includes more aggressive shocks and stiffer stabilizer bars, springs, and lower control arm bushings. This suspension is being developed for submission into the SCCA Touring 1 class to compete in the 2015 season. The aggressive passive shocks are used to maintain eligibility to compete within the rules of most club racing sanctioning bodies.

Z06 Brake Concept Ceramic Matrix 6/8

The Z06 carbon ceramic-matrix (CCM) package adds larger cross-drilled rotors (394x36 mm front and 390x32 mm rear), and collectively they save 27 pounds over the standard iron Z06 system. The front, six-piston monoblock aluminum calipers feature vented pistons for improved pad and brake fluid cooling. These calipers offer differentiated piston diameters of 28, 32, and 38 mm (leading to trailing) in order to ensure more even pad pressure and, thus, wear. The rear four-piston calipers features 30 and 32 mm differential diameters as well.

Z06 Quarter Vents 7/8

Substantial airflow is critical to maintaining cooling performance on the track. The Z06 quarter vents offer larger openings for a 25 percent increase in airflow to the transmission oil cooler and differential cooler compared with the Z51 at track speeds. The larger Z06 rear transmission cooler fits in the same location as the base/Z51 cooler, but it adds up to 15 percent more cooling. The Z06 front auxiliary transmission oil cooler takes fluid to the front of the car for additional cooling, doubling the fluid capacity. And the 600-watt radiator fan (up from 500-watts, for increased fan speed) was designed specifically for the Z06’s track cooling requirements.

Z06 Chevrolet Corvette Wicker Bill 8/8

The adjustable wicker bill (aka Gurney flap) on the Z06 provides more downforce, offsetting the lift of the body shape, for better road holding and handling. Different levels of aero packages are available, from track to moderate. Dickens points out that on some tracks you want more downforce for quicker lap times; on others you want higher straight line speed, so the rear spoiler is smaller or even removed entirely.



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