Before we get to the numbers, if you're not familiar with MT's Real MPG setup then you should check out the details on the protocol. It involves specially-developed standardized fuels provided by Chevron to ensure consistent energy density, two external labs - one that runs the tests and one that handles the fuel, numerous testing system calibrations, and then driving an 88-mile route on Los Angeles roads that's cued off the lab-only EPA test cycle. The highway portion is driven six times and the city portion is driven four times to account for traffic, environmental, and climate control factors. Afterward the on-the-road mpg data is modeled against the speed data and road profile. If a tested vehicle falls too far outside an acceptable profile limit it is tested again to make sure the data is valid.
That is what the diesel Titan XD, with 310 horsepower and 555 pound-feet of torque, had to go through to return 17.7 combined mpg. The puts the tweener Titan - said by Nissan to have a max payload of 2,000 pounds and a tow rating of "12,000-plus pounds" - betwixt the two diesels in the Ram truck line, the only other diesel trucks to far tested in the Real MPG program. The four-wheel-drive Ram 3.0-liter 1500 EcoDiesel Crew Cab scored 18.3 city, 27.2 highway, and 21.6 combined, the four-wheel-drive Ram 3500HD Laramie Longhorn Crew Cab with a 6.7-liter Cummins returned 14.1 city, 17.6 highway, and 15.5 combined mpg. We'll know more when we get into it next month, but the bell for round one is rung.