For the past couple of years, the premiere American luxury marque made great changes to its lineup in order to reinvent itself. After Cadillac had established its mid-level CTS and entry-level ATS, the development of the latest CT6 marks the true return of Cadillac and its intention to challenge its German luxury counterparts.
In order to get a better understanding, we spoke to CT6 head engineer Travis Hester about a number of key points on the new Caddy. Let’s get started:
1.) Design intent: The new CT6 is Cadillac’s interpretation of “Goldilocks.” While the CT6 is intended to rival against the top-tier Mercedes-Benz S-Class, BMW 7-Series, and Audi A8 in space and comfort, Cadillac benchmarked the ride and handling and characteristics to smaller cars like the ATS, CTS, and BMW 5-Series, Mercedes E-Class and Audi A6. Unlike the floating luxo-barge full-size Cadillac sedans of the past, the idea behind the CT6 was to deliver a nimbler, firmer, and more dynamic driving experience in a full-size package.
2.) Structure: In order for the Cadillac CT6 to combine full-size luxury with the responsiveness of a smaller footprint, a light yet rigid chassis will be necessary. GM developed a brand-new architecture known as the “Omega platform” for its new full-size luxury Cadillac CT6.
According to Travis Hester, the Cadillac CT6 platform finds strength through the combination of lightweight materials and the utilization of advanced casting technology. In order to better explain what that all means, Hester took us around a CT6 cut-out displayed at the New York Auto Show for a closer look.
First, you will notice an intricate construction that mimics an unfolded fan wrapping around the wheel well. This particular casting begins at the shock tower and ends at the base of the CT6.
According to Hester, past technology will require 35 sheet metal pressed parts welded together to form that sort of structure. However, every weld or rivet to join two pieces of metal will inevitably become a point of flex and looseness over time. In the 2016 Cadillac CT6, you are looking at one single component. Eliminating 35 components by engineering a single piece effectively achieves lightness in an area as well. What’s more, this technique is applied to every single part of the new CT6 platform.
Although we’ve explained the benefits of a single-piece casting, we still haven’t explained why Cadillac created the interesting ribbed-fan cluster on the structure. According to Hester, ribbings that are closer together offer higher strength and rigidity to a critical stress point. At the same time, Cadillac can also consider maximum weight saving at other areas by utilizing less ribbing where stiffness is not necessary. In the past, pressed components were created at a uniform thickness that was dictated by the critical stress point. Unfortunately this would also cause unnecessary mass at areas that do not benefit from the thickness at all.
While Cadillac acknowledges the extensive use of aluminum is necessary to keep the weight down, the engineers also understand that they are trying to build a comfortable luxury sedan and not a Lotus Elise. One drawback of a full aluminum structure is that the metal is also prone to noise, vibration, and harshness that will be uncomfortable for the occupants. In order to achieve the level of ride comfort expected from a full-size luxury car, a very thick and heavy layer of acoustic material that will negate the weight-savings of the aluminum must be applied. After a series of trials, the engineers ultimately decided to use thin steel with much thinner acoustic material in the base of the cabin cell instead. Essentially, the Omega platform is now aluminum at the extremities and steel with aluminum bracing in the middle.
According to Hester, it would have been a lot easier to simply make everything out of aluminum or everything out of steel. However, the aluminum and steel hybrid of the Omega platform optimizes both structural rigidity and lightness as well as a comfortable NVH for the passengers.
All in all, GM claims that the new Omega platform for the Cadillac CT6 is an achievement in stiffness and weight. In fact, the CT6 architecture will weigh even less than the underpinnings in the mid-size CTS. According to Cadillac, the new CT6 luxury car will weigh below 3,700 pounds. In comparison, both the Audi A8 and BMW 7-Series weigh at least 600 lbs. more at 4,365 lbs. and 4,344 lbs., respectively.
3.) Wheels and Suspension: In close correlation to the chassis dynamics, the ride and handling of the Cadillac CT6 is further optimized with state-of-the art suspension design, which features a standard multi-link suspension set up as well as an optional Active Chassis System, which consists of rear-wheel-steering as well as Magnetic Ride Control active dampers.
In fact, the rear-wheel-steering is one of the fundamental designs that allows the long-wheelbase full-size Cadillac CT6 to reproduce driving characteristics of the smaller ATS and CTS. The rear-wheel-steer is capable of rotating up to 3.5 degrees in order to bring the turn circle down to a tidy 37-feet.
4.) Powertrain: The Cadillac CT6 engine options will initially consist of a turbocharged 2-liter 4 cylinder producing 265hp, a 3.6 liter V6 producing 335hp, and finally a range-topping twin-turbocharged 3.0 liter V6 producing 400 horsepower. All these engines will be mated to GM’s 8-speed gearbox. At the New York Auto Show, the specific cut-out on display featured an all-wheel-drive layout, which offers a power bias of 20 percent front and 80 percent rear in Sport mode and a 50-50 split in Snow/Ice mode.
According to Hester, a future V8 model will be developed, but Cadillac will not go into further details regarding the V8 powerplant until the Shanghai Auto Show later this month. What’s more, even though a V8 version has been confirmed, there is no word as to whether or not Cadillac will use the CT6-V high-performance moniker in the future.
5.) Future Models: Beyond the future V8 CT6 model, Hester also hinted that there will be “some announcement of Hybrid capability in Shanghai.”
Finally, he also emphasized that the Cadillac CT6 is intended to compete against the short-wheelbase versions of the Mercedes-Benz S-Class, Audi A8, and BMW 7-Series. A future model, tentatively called the “CT7,” will accommodate customers that prefer an extended wheelbase version.
By Danny Choy
Photos copyright Carscoops.com / Danny Choy