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.