By on March 16, 2015

Cadillac CT6 Structure mit Aluminium und Schteel Jawohl Uber Alles Amerika!

While the Cadillac CT6’s exterior may leave the B&B wanting, its lightweight structure may be more impressive.

Cadillac says its upcoming flagship — set to bow March 31 before rolling down the ramp at the 2015 New York Auto Show — uses 13 different materials throughout the chassis and body panels to bring the CT6’s weight down by 198 pounds when compared to a similar model using “predominantly steel construction.”

Per president Johan de Nysschen:

This is the rocket science of automobile construction and manufacturing today. With the CT6, we used high-strength aluminum and high-strength steels; lightweight chassis components; we integrate aluminum and steel where it makes sense; we eliminate every gram of mass possible, while achieving world-class performance.

Most of the vehicle’s structure — 64 percent — is aluminum, with high-strength steel “used strategically to reinforce” the structure, which has 21 patents pending tied to its existence. Aluminum and steel spot welds, flow drill screws, laser welding et al were used to put the structure together. The results eliminate the need for extensive sound-deadening, and allow the CT6 to be bigger and have more standard equipment “while achieving lower overall mass,” according to executive chief engineer Travis Hester.

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35 Comments on “Cadillac CT6 Lighter Than Similar Sedans Via Patent-Pending Construction...”


  • avatar
    Hummer

    A twin-turbo LT 7.0L engine could have made up for the extra weight, just like apples never ending pursuit for paper-thin electronics, the auto industries never ending pursuit to using the most expensive material possible has to end somewhere.

    • 0 avatar
      Speed3

      It’s called technological progress. If the market really demanded twin turbo 7 liter engines, then wouldn’t every automaker be selling them in droves?

      I get that everybody on this website is jumping at the opportunity to call Cadillac a failure, but just because they don’t make the vehicle you want doesn’t mean everything they do make is garbage.

    • 0 avatar
      sproc

      Why is that? Assuming for a moment this is actually state-of-the-art engineering versus marketing hyperbole, reducing weight through lighter materials and better manufacturing sounds like a win-win to me, whether it’s a halo sedan or a stripper sub-compact. New techniques are usually expensive, so of course they’re going to debut in high-end models.

    • 0 avatar
      Mr. Orange

      How is steel and aluminum “the most expensive material possible”? Haven’t cars been made out of both of those for decades now.

      I could understand your if it were carbon fiber, titanium or whale-p*nis leather. But isn’t the segment this car will compete in aluminum construction is common.

  • avatar
    wmba

    Well, it all “sounds” good. Presumably they have rolled back the laws of nature and have a patent on avoiding galvanic corrosion between steel and aluminum.

    • 0 avatar
      Verbal

      You beat me to it. This car looks like galvanic hell. More important than the mix of metals is the steps they will have to take to seal and finish the dissimilar metals. Otherwise, look for rust belt CT6s cracking in half in ten year’s time.

      • 0 avatar
        DeadWeight

        I am genuinely looking forward to CrabSpirits wonderful stories urrounding salvage yard Cadillac CT6s (aka CTLEE-EightySixers) in the approximate year 2021.

      • 0 avatar
        wumpus

        Looks like it, but shouldn’t be (but don’t bet GM somehow manages). You can’t weld Al to steel, and unless they can find matching alloys I would count on significant heat expansion rates. I’d hope they use some sort of epoxy bond that separates the two metals.

        Prediction: that’s how the engineers designed it. Then some bean counter will redline it* to something cheaper which will rust through in 5 years after being loosened up by thermal issues.

        * I remain convinced that Hyundai’s warranty will be rememberd more for curing this disease at Hyundai than convincing buyers that they are a safe buy.

    • 0 avatar
      Russycle

      Given GM’s long, successful history of innovation without compromise, i’m sure there’s nothing to worry about here. Snark aside, I expect GM’s engineers are aware of the galvanic issue, and hopefully new GM won’t let the bean counters pull a “Hey, we can save $2.50 a car by deleting these anti-galvanizing compounds, and no one will notice!” Time will tell.

    • 0 avatar
      chaparral

      We fasten steel and aluminum parts together all the time and don’t have any problems with galvanic corrosion. The key is – for a battery to work, there have to be four things – an anode, a cathode, an electrolyte, and a current path between anode and cathode. A plain bolted joint between a steel part and an aluminum part has all four, with the path being the contact between steel and aluminum and the electrolyte being any salt water that gets into the joint.

      If you E-coat both parts, you’ve sealed them both off against electrolyte contact and have eliminated the conductive path. Most modern riveting technologies provide a hermetically sealed joint – nowhere for electrolyte to get in – and some joining tech can even avoid destroying the E-coat.

      Now, if you were to repair this thing by drilling out the rivets, oversizing the holes, and pop-riveting the panels back together, you’ve just allowed the electrolytic corrosion a great place to start. So don’t!

  • avatar

    That is all fine but how is a car about the same size as a CTS also looking very similar but way more expensive going to save the brand? I called Cadillac out more than a year ago warning them the need to have 2 additional crossovers(one smaller and one larger than the SRX)and an updated SRX asap. I will work for charity and do a better job than the clueless idi0ts running this brand.

  • avatar
    sportyaccordy

    We will see. NSX was not much lighter than comparable 911s. A8 was not much lighter than comparable 7s and Ss. Most recently, the Jag XE/F-Types are flat out HEAVY, and the F-150 is only lighter than previous F-150s, which were overweight. The promise of aluminum has yet to be met, from what I’m seeing, and I have a strong feeling this CT6 will be no exception.

    • 0 avatar
      redav

      Well, they claim it cuts ~200 lb.

      Considering Mazda dropped nearly that much on the new Miata (which was already light weight), it doesn’t sound so impressive.

  • avatar

    This may very well be innovative and set a standard in materials construction, but unless its wrapped in a similarly-compelling wrapper, few outside our car nerd sphere will notice.

  • avatar
    319583076

    How repairable is this scheme?

    Seems like a fender bender may cause this thing to be totalled.

    • 0 avatar
      danio3834

      Shops with the capability often charge double the labor rate to work on aluminum bodies. So yeah, it’ll be more expensive, but with Al bodies going more mainstream, the cost will eventually come down.

      • 0 avatar
        raph

        Its a composite structure using new joining methods, I bet GM will have to train aurobody shops on how to repair it as well as source any special equipment needed.

        I can see where 319’s reply has merit. When BMW first introduced the bonded aluminum sub-frame cats inurance was expensive because most shops couldn’t repair the car and insurance companies just totaled them out for what would have been a repairable car with more conventional construction.

      • 0 avatar
        319583076

        I don’t see Aluminum structure repairs as comparable to Aluminum body repairs. The acceptable tolerances on structural elements will be much narrower than those on body panels. Similarly, body panels are amenable to tricks that cover up fit and finish problems whereas structural elements are not.

        • 0 avatar
          redav

          Also, aluminum in the strengths needed to be beneficial has poor toughness & fatigue life compared to the steel it replaces.

          Steel structures can be bent back into place and generally be fine. These aluminum alloys may not survive the bend-back process, thus necessitating totaling the car regardless of availability of repair equipment.

    • 0 avatar
      28-Cars-Later

      “How repairable is this scheme?”

      Good question. Couldn’t there be a planned obsolescence scheme at play here?

  • avatar
    DeadWeight

    ” president Johan de Nysschen:

    This is the rocket science of automobile construction and manufacturing today. With the CT6, we used high-strength aluminum and high-strength steels; lightweight chassis components; we integrate aluminum and steel where it makes sense; we eliminate every gram of mass possible, while achieving world-class performance.”

    Johan flaps gums & says blah de blah, *marketing speak* blah zippety doo dah.

    In other news, Cadillac’s upcoming “range topping” sedan still can’t shed even a fraction of as many pounds as a % of its overall curb weight (using such “exotic materials” to Cadillac as “aluminum”) as a Mazda MX-5 likely costing 35% as much as the CTDeepEightySixLEE which will have rebates as high as the former Berlin Wall on its hood within a year of going on sale.

    • 0 avatar
      Richard Chen

      http://www.autonews.com/article/20150316/RETAIL01/303169995/tier-2-luxury-brands-struggle-to-compete-with-elite-germans-lexus

      FTA:”De Nysschen is frank about the yawning gap between Cadillac and the German stalwart brands, from sales volumes to brand image to the breadth of the vehicle lineup. To close that gap, he’s trying to emulate those brands — not in car design and brand identity, but in mindset. He wants Cadillac to act like it’s an exclusive luxury brand, which requires tighter production and firmer pricing to avoid the all-too-frequent Cadillac fire sales that damage its resale values and image.”

      But that product is some time off, and for now Cadillac now is behind Acura in 2015.

      Wait, what?

  • avatar
    MrGreenMan

    Did not America already remove 200 lbs from the driving load by having fewer children?

    This STS is one spiffy looker; like a CTS but a little longer. With its Cadillac-exclusive engine – bred for racing, I sincerely hope – I’m sure it will give exactly the jolt that an America tired of Middle Eastern/South Asian wars needs to aspire to get back to work.

    Edit: Will I still be able to attach a magnetic ribbon declaring how much I’m better than everyone else because I Care? How about the magnetic sticker for my “consulting” business so that I can deduct the lease payments?

    • 0 avatar
      DeadWeight

      It’ll be cheaper to lease a MB E Series and not much more to lease a MB S Class – have you looked at Cadillac’s horrific residuals (they make for some truly hideously non-competitive lease rates)?

  • avatar
    28-Cars-Later

    “uses 13 different materials throughout the chassis and body panels to bring the CT6’s weight down by 198 pounds when compared to a similar model using “predominantly steel construction.””

    Cool, but that’s maybe a 5% or so weight reduction on a 4,000lb or more car (or is the percentage much higher due to the 200lb figure being on an unassembled chassis I wonder?).

  • avatar
    oldowl

    Not yet revealed: A drone at each of the four corners will lighten the weight even more.

  • avatar
    nickoo

    Big mistake, those 200 lbs aren’t going to get customers in the door and galvanic corrosion is going to be a nightmare. In manufacturing, we have a saying, exploit the knee in the curve. In other words, in the cost/features curve, you shoot for 80% features at 25% cost rather than 100% features at 100% cost. Especially when it comes to those features that the customer will not even care about. Hyundai Genesis is the type of car caddy should be building, no one who wants an s class is going to accept anything made by the crest and wreath.

  • avatar
    gsp

    That I am aware of, BMW, Audi and Porsche have been doing this for years in this segment. The Audi A8 was all aluminum in 1994!

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