Cadillac's new CT6 sedan arriving later this year is a huge deal for the company. Along with replacing the awkwardly positioned XTS in the carmaker's lineup, the full-size RWD sedan is meant to further establish Caddy's presence in the luxury performance market by taking direct aim at its extra-large competition—specifically the BMW 7-Series, Audi A8, and Mercedes-Benz S-Class.
To that end, Cadillac developed a whole new lightweight platform for the car that the company says is one of the most advanced its ever built. Named Omega, the chassis uses 11 different materials and a strategic mix of high-strength steel and aluminum to save an impressive 198 pounds over using steel.
A key element of the Omega platform is its 13 aluminum castings. As seen in the rear-wheel-well example above, the castings are impressive feats of engineering themselves. Using computer modeling, Cadillac created a ribbing system that requires the least amount of metal possible while also maintaining the chassis's structural integrity.
"Ribbings that are closer together offer higher strength and rigidity to a critical stress point," says Travis Hester, executive chief engineer for the CT6. "We can also consider maximum mass saving at other areas by utilizing less ribbing where stiffness is not necessary."
By reducing the number of parts needed, the large castings also lower the number of stress points within the structure. "Where we would traditionally use 35 stamped parts, we can now only use 2 parts," Hester says. "Every joining point is a point that can potentially flex over time." Overall, the new Omega structure uses 20 percent fewer parts than Cadillac's Alpha platform currently underpinning the ATS and CTS.
To further shave pounds, the CT6 uses weight-saving assembling methods and aluminum body panels, making the car 64 percent aluminum in total. Cadillac estimates the CT6's final curbside weight to be less than 3,700 pounds. That's CTS territory, even though Caddy's mid-size sedan has a wheelbase that's 8 inches shorter than the 122.4-inch CT6.
More notably, the majority of the CT6's full-size competitors weigh in at more than 2 tons. That should give Cadillac an edge in both performance and fuel efficiency.
