Scoop: GM Flexes Alpha Platform Options

Last month, we reported that the new rear-wheel-drive General Motors platform, Alpha, designed for the 2013 Cadillac 3 Series-fighter, also will underpin the 2014 CTS and 2015 Chevrolet Camaro. The platform is proving flexible enough to serve as the basis for expensive Cadillacs as big as the next CTS, which we expect to grow to about 195 inches long, plus a smaller Chevrolet and/or Buick sedan, as well as the next-generation Camaro.

Now 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.

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.

The Alpha four-cylinder almost certainly will be the '15 Chevrolet Camaro, which should be somewhat smaller and much lighter than the current model. A turbo- or supercharged V-6 could be the Camaro's premium engine, though of course, a lightweight, Hyundai Genesis-size Z/28 with a small block would be killer.

The 3 Series-size Cadillac, codenamed ATS, obviously would get naturally aspirated and breathed-on V-6s, probably of the current 2.8 (but with gas direct-injection) and/or 3.0-liter configurations, and maybe the 3.6. However, Mercedes and BMW are planning to sell C-Classes and 3 Series in the U.S. with four-cylinder engines (and Audi already is there with the A4/A5 2.0 TFSI), so a 2.0-turbo or 2.4-liter four in the ATS wouldn't be a surprise.

The new, bigger, Alpha-based CTS will stick with 3.0- and 3.6-liter high-feature engines, of course, but given where the competition is looking, a turbo four could be in its future. As we reported before, the Mk III CTS will again be sold only as a sedan, with no coupe or wagon variants. The ATS will get multiple bodystyles instead, including probably a convertible. The bigger question may be whether a small block or a turbo 3.6 powers a next-generation CTS-v.

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 to make it economical. An eight-speed automatic would be a very expensive component in the traditionally low-cost, high profit margin Chevrolet Silverado.