27 MPG in a 2009 Cadillac Escalade Hybrid

Technology is a beautiful thing. This thought occurred to us yet again while behind the wheel of one of the last vehicles most eco-conscious Green Car readers would expect to find on these pages. In fact, not since Doc Brown’s flux capacitor tweaked time and space in Back to the Future has technology proven itself so well. Okay, so maybe that’s a stretch, but the vehicle being piloted is BIG American Iron – more than three tons of cushy luxury brought to the pavement in a full-size SUV – with technology allowing it to achieve fuel economy that trumps most compact SUVs and minivans.

With an infusion of GM’s two-mode hybrid powertrain, a vehicle as over-the-top as the Cadillac Escalade can deliver surprisingly good fuel economy. Green Car recently pushed the limits of such a vehicle to see just how efficient this mammoth could be. The EPA’s official numbers are 20 mpg city and 21 on the highway. Like the Chevy Tahoe Hybrid – last year’s Green Car Journal 2008 Green Car of the Year® – that’s an astonishing 50 percent improvement in city fuel economy and on par with some mid-size cars weighing half as much.

Our first cruise on the interstate was in the worst possible conditions for maximum fuel economy. We were in heavy rain, traffic, and the temperature was in the upper 30s. Keeping with the flow of traffic, the Escalade Hybrid delivered 22.1 mpg. As conditions improved we were able to cover a combined city/highway leg at 25.6 mpg, still on wet roads.

The most impressive performance was in a heavier city mix that included 50 mph country roads from our home base to the grocery store. This real world test, on a route we do regularly at 21 mpg in a Honda Pilot, was truly an eye opener. Using high mileage driving techniques while being careful not to impede traffic flow, the Escalade Hybrid made the 15 mile trip with an average of 26.7 mpg. Even when we weren’t particularly paying attention to our driving style, economy seldom dipped below 20 mpg … and our test unit was a less efficient four-wheel drive model.

Pulling away from a stop silently on electric drive is an interesting experience in a rig that weighs over 6,000 pounds. You can accelerate to over 20 mph on electric drive, an important feature since low speed zones are where heavier vehicles are the least efficient. It takes a lot of energy to set that much weight in motion from a stop. GM’s two-mode handles the low speed realm with little complaint. At higher speeds, the two-mode offers the advantage of electric assist for typically fuel-robbing passing and ascending hills.

The Escalade Hybrid offers another fuel saving strategy at times when little energy is required to maintain momentum on level ground. GM is using Active Fuel Management to decommission four of the engine’s eight cylinders when they aren’t needed. In other words, the Escalade Hybrid’s V-8 becomes a V-4 during times of low-load driving. With the cruise set to 55 mph on level ground in no-wind conditions, the Escalade Hybrid slipped smoothly into V-4 mode with an instant fuel economy reading that ranged from 26.4 to 27.0 mpg.

Cadillac’s Escalade certainly isn’t lacking in power. The 6.0 liter V-8 produces 332 horsepower and 367 lbs-ft of torque, and along with the pair of low- and high-speed 60 kW electric motors, acceleration and load carrying capability are quite good. We recorded a 0-60 mph time in the high eight second range. Despite all the luxury amenities, the Escalade Hybrid is a workhorse, too, capable of carrying eight passengers, a bunch of gear, and towing a 5,800 pound trailer.

As you might expect, the interior is a very comfortable place to watch the miles roll by. While you are constantly reminded that the Escalade Hybrid is a big, heavy vehicle, it’s not difficult to drive and handles most conditions with little complaint. Ride is only mildly compromised by the massive 22-inch seven spoke alloy wheels and P285/45R22 performance tires, which help steering response considerably.

The 2009 Escalade Hybrid clearly isn’t for everyone, and with an MSRP starting at $71,685 it addresses a highly targeted market. Those who demand a luxury class vehicle and need the versatility of eight seats and impressive load handling capability could certainly do much worse.

The Good: Surprisingly good fuel economy and performance
The Bad: Sticker price, wretched excess
The Rating: 7 (out of 10)