It's no coincidence GM has just come out with its own all-aluminum twin-turbo V-6; after all, Ford's EcoBoost engine is the best-selling power plant choice in the half-ton class, and it makes good business sense for GM to spread the costs of engine development over the widest possible product plan rollout.
That's why we'll see the new powertrain and transmission in Cadillac first, then maybe in the Camaro or a smaller Corvette after that, then on down the food chain. But make no mistake; this engine will be dropped into the new full-size GM platform.
In the same way the engine first is put to work in a Cadillac, we fully expect the first pickup truck to grab the premium V-6 to be the GMC Sierra, possibly a new Sierra Denali 1500. Although we've heard no official confirmation from GM, there are several reasons why this is a no-brainer.
First, turbos do wonderful things for torque curves. A normally aspirated V-8 typically reaches its torque peak somewhere around 4,000 rpm, with a slow ramp up and a very fast drop off. The EcoBoost and the new GM engine behave much differently, thanks in large part to high-pressure direct injection and two small exhaust turbochargers. From our experience with the EcoBoost, we've seen as much as 90 percent of the engine's available torque start at 1,700 rpm and last clean through 5,000 rpm.
Even the test data GM provided in its Cadillac CTS press release noted the new 3.6-liter motor would have a relatively flat (we'll assume at least 90 percent) torque curve from 2,500 rpm to 5,500 rpm. For towing performance in particular, it is a huge advantage to have that much of the available torque accessible in a lower and wider range of engine speeds. Not surprisingly, those characteristics are more in line with big-hauling, heavy-duty turbo-diesel engines like the Cummins, Power Stroke and Duramax.
Additionally, when not towing or in a heavy-hauling situation, and when feather footing the truck around town empty, the engine will behave like a basic V-6 engine, weighing quite a bit less than a comparable V-8 and providing much better around town and highway fuel economy.
Although the only fuel estimates (17/25 mpg city/highway) GM provided in the press release relies on factors that include a smaller, lighter car sedan platform, we're guessing it won't drop by much when tested inside a Silverado, which some insiders have told us could offer several lightweight platform packages. It's also possible GM will put this new Silverado twin-turbo V-6 through EPA testing procedures with regular fuel (although Cadillac specs show premium fuel will be required) and take the initial hit in power output and possibly fuel economy in order to be able to say the mainstream Silverado will run on regular fuel, just like Ford's EcoBoost. We should note Ford tells us that its power outputs improve slightly, measuring 385 horsepower and 430 pounds-feet of torque when using premium fuel, instead of the regular fuel the owner's manual recommends.
What will all this mean in a Silverado? We'd like to think the new technology means better choices for truck customers, giving them more capability with fewer tradeoffs. Technology updates such as this — powertrains that let us have our cake and eat it too — are always hugely appreciated.