2020 Corvette Uses 40% Aluminum Extrusions in Space Frame
In 2014, Chevy unveiled their 7th Generation Corvette with an all-aluminum frame. Now in 2020, Chevy has taken the Corvette to a new level – and aluminum extrusions are a key factor in improving performance.
“We were reaching the limits of performance with our historic (front-engine) architecture” stated one of the Corvette C8 project engineers. Hence, the move to a mid-engine design with an aluminum-intensive “uni-frame”.
The engine location is a first for Corvette. The aluminum-intensive frame is evolutionary, building on experience gained with special-edition C6 Corvettes and the aluminum structure used in total for the seventh generation.
The C8 uni-frame departs substantially from the C7 design, which was more of a traditional “rocker dominant” frame with side rails running from front to back. The C8 has moved to a “tunnel-dominant” architecture.
A particular concern was improving torsional stiffness in the base vehicle, offered as both an open-roof coupe and a convertible. An 18% improvement in stiffness over the C7 is reported, as is a 54% improvement over a “primary competitor.”
What hasn’t changed is the extensive and creative use of aluminum. Forty percent of the structure is extrusion – mostly 6xxx series alloy. There appear to be approximately 25 separate profiles, including the tunnel upper, rocker sections, crush cans, windshield structure, crossmembers, and other parts. Another 18% of the structure is aluminum castings, up from 8% in the C7 and comprising much of the rear structure, as well as front shock towers. Thirty nine percent of the structure is comprised of aluminum stampings. What’s left? A cast magnesium instrument panel, a carbon fiber rear bumper beam and a carbon fiber under-tunnel close-out panel … and two small steel struts in the front end.
The assembly process has evolved since the C7, as well, with MIG welding cut by half and three times the adhesive use of the C7. Over 1200 mechanical fasteners are employed, with nearly 200 rivets and over 450 flow-drill fasteners.
For Corvette enthusiasts, who have been waiting for a mid-engine 'Vette for years, the real question is not how it’s made, but how it performs. To date, there are just a few published road tests – and those of pre-production vehicles – but the emerging consensus is that the C8 is radically better. It reportedly has a much better ride, better handling, sub-3-seconds 0 to 60, and all at a starting price just under $60,000. The “how it’s made” is certainly a major contributor to that assessment.
2020 Chevrolet Corvette Stingray, Chevrolet 2020 Corvette Stingray Media Site, Creative Commons 3.0; C-8 cutaway images, Car & Driver magazine