By on April 20, 2010

First developed by Holden in 2004, GM’s Zeta platform now underpins vehicles as diverse as the Statesman/Lumina/G8/Caprice sedans, and the Chevy Camaro. Originally designed for full-sized , rear-drive Australian sedans, Zeta was downsized as far as it could be for the Camaro, which reviewers largely view as overweight and rather too ungainly for true sportscar status. Accordingly, GM has been developing a new rear-drive platform known as “Alpha,” which will form the basis of GM’s performance and luxury RWD models for the considerable future. Last we heard about Alpha was last August, when Bob Lutz swore there was no development underway of the platform he compared to BMW’s 1-/3-series. According to Motor Trend, work on the Alpha platform has begun… but there are already signs of trouble.

MT’s big scoop is that GM is “flexing” the Alpha platform. So what the hell does that mean in Ed Whitacre industry-novice-speak?

we’ve learned that the platform is being “protected” for a variety of engines, including four-cylinders, supercharged or turbocharged V-6s, and the small block V-8. By “protected,” we mean the bodies are designed to allow for proper fitting of the various engines, whether they are offered with all the engine choices or not. You don’t “close off” the design to make it impossible to add a different engine or transmission initially unplanned. While four-cylinder engines are smaller than sixes and eights, of course, the cars also must accommodate active engine mounts to account for less inherent refinement and smoothness in the fours.

On the surface this seems like a hefty dollop of awesome. By building flexibility into its new platform, GM will be able to offer cheap, efficient four-bangers in budget enthusiast models (the next-generation Camaro will be based on Alpha) and big V8 power in extreme V-series versions of the Alpha-platform Cadillac, known as the ATS , as well as the next-gen CTS which will also be based on Alpha. Scratch a little deeper though, and some of the problems with this strategy reveal themselves.

The major issue with making Alpha capable of a full engine range is the perennial bane of the Zeta platform, namely weight. In fact, weight concerns were the very reason Hyundai decided to ban V6s from its new Sonata sedan. As Hyundai NA president John Krafcik explains in this video, by not having to engineer V6 and four-cylinder hardpoints, Hyundai’s developers were able to trim significant amounts of weight and mass from the Sonata. And with recent breakthroughs in direct-injected, turbocharged engine technology, they’re giving up little to nothing for the added lightness.

The problem for GM is that it’s invested so much in its power-mad Cadillac V-Series badge that it can’t develop the platform that will underpin the next CTS-V without at least leaving room for a “breathed-on V6.” Which, as MT explains, means they might as well just make it capable of rocking a small-block V8 as well:

Breathed-on V-6s need engine bay accommodation for the blowers or turbos, and for intercoolers. This makes it easy to protect for a small block — overhead valves are more compact at the engine’s top than dual overhead cams with four valves per cylinder. Therefore, they fit more easily than the breathed-on sixes.

Meanwhile, there’s another problem:

These plans are fluid. GM is said to be in a quandary over the transmission designed to accommodate these cars. It’s developing an eight-speed automatic for its V-6s. The question is, will the eight-speed be designed for front-wheel-drive or rear-wheel-drive?

Before you say, “both, of course,” be aware that new transmissions are very expensive. Adapting an eight-speed for both FWD and RWD can double the already healthy cost of doing it for just one configuration. And while BMW and Lexus eight-speed automatics so far serve only RWD-based cars, if GM decided to design it for transverse mounting, it would serve a much higher volume of cars and trucks.

If it designs the transmission for RWD to better compete with BMW and Lexus, it probably would have to add the transmission to trucks and big SUVs in order to get enough volume

Weight and expense problems? Trying to develop a single platform that’s capable of competitively executing every RWD application across several brands? Compromising mainstream variants in order to justify the insane engine requirements of low-volume halo versions? Does any of this sound like a new day for GM’s RWD reputation to you? Don’t get me wrong: a sub-Zeta RWD platform is a great idea (in Cadillac’s case, probably an existentially necessary one), and my inner enthusiast thrills at the idea of both budget RWD treats and tiny, loony supersedans. But the last thing I want to see is GM spending taxpayer money developing a platform that tries to fill too many niches, only to end up a dud of a compromised-to-death mess. Sure, platforms are becoming more flexible but so are engines. With the Pontiac Solstice GXP’s Ecotec DI four-pot already making 260 horsepower, and with downsized, direct-injection turbo engines poised to become the short-term future of the car industry (to say nothing of CAFE), GM could make the Alpha platform four-cylinder-only and make up the performance difference with the reduced curb weight and engine technology. Too bad it probably won’t.

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27 Comments on “GM Alpha Platform: All Things To All Enthusiasts?...”


  • avatar
    th009

    So Hyundai trimmed both weight AND mass from the Sonata?

    Wow. Maybe South Korea has a special gravitational zone where the two can be reduced independently, but on the rest of Planet Earth, weight and mass go hand in hand, and reducing one reduces the other.

  • avatar

    Small nit to pick: the Cadillac CTS is on Sigma, not Zeta.

    One thing to keep in mind is that the OHV small block V8 is a very compact engine and likely weighs close to (if not less than) what the 3.6 liter DOHC V6 does, and also likely takes up less underhood room.

    • 0 avatar
      KixStart

      How is GM going to market an OHV engine in a DOHC world?

      J. Jackson Winecase (you know, Joe Sixpack with money) undoubtedly thinks that DOHC is a “modern” high performance engine and an OHV engine is what was in his father’s Oldsmobile (which it was).

    • 0 avatar

      The current Sigma II platform that the CTS uses borrows certain parts from the Zeta platform. So TTAC is correct here.

    • 0 avatar
      Alexdi

      Specious logic, Shoichiro. It’s a legitimate error.

      Why all the love for four-cylinders? There’s not much luxury there, boosted or not. I’ve yet to drive one I’ve liked half as much as a smooth six. If you commit to a four, you’re also committing to a maximum displacement of about 2.5L and a power cap of 350 HP. With BMW and Infiniti putting out mainstream 4-doors right now with 330 HP, a range-topper with 350 off in the future won’t be competitive and won’t have any room to grow.

  • avatar
    stationwagon

    Can’t they just make different engine mounts and engine bay sizes based on the engine it will carry. It is not like one factory makes the platform/frame and another factory attaches the body and interior to it. How about the use a short wheel base small engine bay for a roadster, use the v6 v8 engine bay for the camaro and ats, and use a bigger engine bay for the cts-v. I don’t really understand this talk of “platforms” when talking about unitized/monocoque cars. Does a pontiac g8 actually have an engine bay the same size of a cts, cts-v, and camaro? GM and other car makers might need to expand their manufacturing abilities.

    • 0 avatar
      Mark MacInnis

      Ya gotta understand modern auto assembly and procurement. Most likely, the engine cradles/front suspension crossmembers that contain the hardpoints to which the engine mounts and drive train bits are bolted are PURCHASED components, not made in house. It is preferable, generally, to have these components capable of underpinning all of the possible permutations of of vehicles made on a particular line. Failure to do so will necessitate MULTIPLE versions of these parts be available for the manufacturing process at all times. Then, they need to be engineered to be idiot proof in the assembly, so the wrong part can’t be put in the wrong vehicle. All of this adds cost, and chews up real estate on the assembly line floor, which is expensive, and which is limited in the time/space assembly equation….there is no “sweet spot” any alternative to fix this problem adds cost, complexity or risk. That is why there is a saying in the automotive industry…You want it fast? You want it low-cost? You want it high quality? Pick two out of three, that is all you are ever gonna be able to get…

  • avatar
    getacargetacheck

    While a small RWD chassis is music to an enthusiast’s ears, the whole idea is folly. Cadillac isn’t doing well with the CTS, and it didn’t do well with the previous SRX or XLR. Audi, BMW and Mercedes-Benz buyers have no interest and will never have any interest in Cadillacs. A cramped, heavy four cylinder Cadillac sold alongside Chevy trucks or GMC crossovers will be less appealing not more.

  • avatar
    rpol35

    This has been done before, look at the ’68 through ’70 Nova; forward sub-frame “F” body with mounts and capacity to handle a 153 CI four cylinder engine; 230 and 250 CI in-line six cylinder engines; 307, 327 and 350 CI small block V8 engines and a 700 lb. big block 396 CI V8 engine.

  • avatar
    zerofoo

    The platform sharing trade-off problem is not unique to GM. My VW GTI shares many things with the Jetta, Passat, and Audi’s entire A series.

    That’s how you end up with a “hot hatch” that weighs 3300 lbs.

    Had the GTI’s platform been better optimized for small cars, the thing might have weighed closer to 2500 lbs.

    -ted

  • avatar

    I partly don’t expect Alpha to see the light of day, especially with Lutz leaving GM.

    I also do not believe it will be successful for Cadillac, which is the big justification behind it in the first place, the CTS is as small and cheap as a Cadillac should be despite what BMW and Audi are doing themselves.

    Neither brand has to worry about colliding with a brand below them like GM does with Buick. Let Buick cover that with the rebadged Insignia and Astra (and who knows what else). GM already has Chevrolet there as well, there is no reason GM can’t sell some well appointed Chevrolet cars like Ford does with the Taurus or like they did in their heyday with the Biscayne and other fullsizes.

  • avatar
    Bancho

    What happened to the kappa platform? Has it been discarded since the Solstice and Sky are no more? Couldn’t it be leveraged to make newer vehicles or did it have shortcomings that precluded that?

    (I’ll admit I loved the Nomad concept they built on a modified kappa platform)

    • 0 avatar

      Kappa was bespoke to the Pontiac Solstice and similar roadsters. It was not designed or intended to be used for any other application. Holden did craft the Torana concept (which was awesome) out of it Down Under but the reality is it could not be produced with what they had.

      It still amazes me to this day that Lutz convinced GM to come up with an entirely unique chassis for just one car and one rebadge. Even though it was cobbled together it still had to cost GM some big bucks to make the Solstice a reality. Also for such a small car it was still quite heavy.

      One very cool fact though is that GM purposely engineered Kappa to easily except LSX swaps. As the roadsters age you can expect to see more and more hot rodders swapping a V8 in them. Kappa also featured a modern turbocharged, direct-injected, intercooled four cylinder before Ford ever started crowing about EcoBoost.

    • 0 avatar
      chaparral66

      The kappa was meant to be a more flexiable platform since the body on frame construction would allow for differences between cars sharing the same platform. I remember the factory was designed around producing multiple low volume models off the kappa platform, which makes sense since the small roadster market is fairly small. The problem is that GM decided to follow the Solstice with another roadster, so it just competed against itself. Then they never followed on with plan to make a variety of niche models on the kappa platform, like the nomad, so it became unprofitable. It is just crazy because they knew the roadster market would not make economic sense, so they designed and built a factory to do more than roadsters. Then they do exactly what they knew would not make money.

  • avatar
    50merc

    How is GM going to sell an OHV V8 in a DOHC world? By boasting about the “high technology advanced ultra-efficient multi-lobe” camshaft design that allows a single camshaft to actuate SIXTEEN valves! Brand X’s camshafts can only actuate eight per cam. See, DOHC is only half as good.

  • avatar
    bmoredlj

    Re OHVs, if it ain’t broke, don’t fix it.

    Even James May admitted the CTS-V wasn’t broke.

  • avatar
    NickR

    So, is it easier to make to start with a smallish platform and stretch it or a large platform and shrink it? It seems to me that the former would be somewhat easier and less inclined to lead to porky products.

  • avatar
    bumpy ii

    By the time Alpha sees the light of day, it’s going to be as big and heavy as the first-gen CTS. Don’t let go of your S13s and E36s just yet.

  • avatar
    Stingray

    To the OHV bashers… high tech is not only limited to dual camshafts and 4 valves per cylinder.

    The Aveo has a DOHC 16V engine, not what I would call a marvel.

    A lot of CFM goes into the design of the head ports and intakes. Just to name one.

    The current LS series engines achieve levels of power only dreamed by the old SBC. Stock x Stock.

    I think it’s not an stigma to have such engines.

    • 0 avatar
      KixStart

      Don’t tell us, tell J. Jackson Winecase.

      Cadillac’s 6.2L engine might be great but the contemporary marketing benchmarks are DOHC and valves per cylinder. The car’s no good if you can’t sell it at a profit.

      In fact, if OHV confers advantages, why doesn’t the Aveo have an OHV engine?

    • 0 avatar
      geeber

      It depends on the market segment, and which company is the recognized leader in that particular segment.

      For full-size pickups and SUVs, OHV engines work. Customers don’t care, and recognize that the GM OHV V-8s are great engines.

      But in most passenger car segments – especially the family sedan and sport sedan segments where fours and sixes rule – buyers view OHV engines with disdain. Honda, Toyota, BMW and Mercedes are the leaders in those segments, and they all offer OHC engines. Like it or not, those companies set the standard in those segments.

  • avatar

    I remember back in 2005-06 Lutz was talking up taking the underpinnings of the next generation Holden Commodore global to do the exact same thing as Alpha here. Be all things to all brands RWD across the globe, thanks to Holden. It’s a shame it didn’t pan out that way. I don’t expect it to pan out that way for Alpha either, GM is too fluid with ideas like this.

  • avatar
    alexndr333

    Of course, GM’s having problems: This is a TTAC article after all. But the rest of the planet knows that a long development process asks lots of questions and takes time getting to the answers. Since GM isn’t at the end, yet, it’s easy to assert its failure. I wonder what would happen if TTAC and the rest of the experts on the American car industry had similar access to the thought processes of the Germans, Japanese or Koreans. Not a chance, of course, so instead we see an open access American industry pilloried based on ignorance of everyone else.

  • avatar
    Dimwit

    I think that the OHV/DOHC thing is overstated. Most buyers wouldn’t give a damn if you said it was running on titanium moonbat parts.
    Their big thing would be 4, 6 or 8? How much? What’s the mpg? How fast and will that affect my insurance? Anyone that it matters to will also know that the GM small block OHV is a sweet engine.

    The big thing here is, how much platform development resources does GM have? Can they afford to have multiple platforms? As it stands now, they might actually pull a VW and have only 3 or 4 platforms for their whole lineup, company wide. It depends on how many plates they decide to support.

  • avatar
    ajla

    Do the Sigma II and Zeta platforms really need replacing so soon? The money being spent on the Alpha platform could be put to use on the Volt, a Northstar engine replacement, or a Cadillac flagship.

    With DOHC vs OHV, GM has a 470+hp DOHC V8 engine they can dust off if they really think it’s necessary for the segment. My guess though is that the V-series sells in low enough quantities that it doesn’t matter what type of engine is used.

  • avatar
    rnc

    I think the big reason why everyone else dropped OHV engines from thier line-up is related to development costs, they could afford to develope advanced, large displacement DOHC engines, where as GM couldn’t so they just kept making incremental improvements to the OHV (also evidenced by the abandonment of the northstar program). Long term this puts you in a position of the improvements you make to one can’t necessarily be transferred to the other, while for the rest the improvements they make to thier 1.4 can most likely be applied to thier 2.0, 3.5, 4.6 and 5.0.

    And through marketing people have been programmed to respond to acronyms like DOHC and VV…..

  • avatar
    joeaverage

    Why isn’t GM making incremental improvements to their platforms rather than throwing the whole thing in the dumpster and starting over? That’s what it sounds like to me.

    Why don’t they create “the best” of their breed and apply it to their luxury cars and then in a generation or two let it trickle down to their bread and butter cars while introducing a new platform for their luxury brands? I’m still not convinced that a “new platform” is really that hard unless they are introducing new engines, new transmissions, new rear axles, and new suspension all at once. That doesn’t seem very wise since they would have potential teething problems in all those systems leading to a 1st gen product that wouldn’t be fit to purchase until the early adopters were done with all the recalls for you.

    Seems to me that GM needs to go on a refinement odyssey on what they already have. Refine the engineering and apply some good looks to everything – not just the halo cars. Does it cost that much more to design a good looking Aveo than a boring Aveo? Creases and curves, not expensive trim components. Absorb some of the cost and pass on some of the cost to the customer. I suppose this is what the LT versions are for.

    I guess the marketing department likes it when when a boring Aveo can shame you into a more expensive GM product that you’re kids wouldn’t be embarrassed to dropped off in front of school in. Frankly when I go shopping if one brand doesn’t offer what I want then I’ll just switch brands, not necessarily go up the corporate product order sheet.

    Engineering refinement could (not necessarily would) lead to better quality and better owner opinions of the GM products. The cost could be minimal if the improvements were made slowly and constantly over time much like VW did with their Beetle in the 60s. Add sound proofing. Tune the suspension a little. Improve the seats a little. Would these incremental improvements cost more than throwing out the whole product every few years and starting over?


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