The new 2014 Jeep Grand Cherokee has an impressive array of appealing new features, but two in particular stand out by delivering vastly improved fuel economy and driving performance. Until now, just two engines were available in the Grand Cherokee. Good as the current V-6 and V-8 are, many Jeep enthusiasts have been asking for a diesel-powered Grand Cherokee.
Now a third engine choice is available, a new, 3.0-liter, diesel V-6 engine that produces 240 horsepower and a whopping 420 lb.-ft. of torque. Named an EcoDiesel by Jeep, it’s capable of towing 7,400 pounds, achieves up to 30 mpg and has a driving range of more than 730 miles.
Full-time 4x4 models have a fuel economy rating of 21 city and 28 highway. Our first test drive, at about 80 mph in the Texas Hill country, produced 29 mpg with two occupants aboard a fully-equipped, 4WD Grand Cherokee Summit with the A/C on full. It was a smooth, quiet ride, thanks to the use of some relatively new technology.
Quiete performance, as well as optimal fuel economy and emissions reduction, are achieved with the Bosch common rail diesel fuel injection system, which accommodates the engine's MultiJet II technology. MultiJet II's Bosch-made injectors can manage up to eight highly precise injections per combustion event. Bosch also supplies the system's high-pressure pump, sensors and engine control unit
The system is solenoid based with an injection pressure of 29,000-psi. The new engine’s 1-4-2-5-3-6 firing order helps manage rotation so neatly it needs no balance shaft to deliver a high level of refinement.
Jeep's new diesel puts to rest some common misconceptions about diesel engines. Ceramic glow plugs heat up quickly, eliminating the annoying wait before starting a cold engine. That loud "cement mixer full of rocks" noise is gone and the foul, black exhaust gas has been cleaned up so it is no longer visible. You can hear the diesel a little at idle, but it's not noisy by any means nor is there any noticeable vibration.
That clear exhaust gas stream results from using a Bosch selective catalyst reduction system, making the engine 50-state compliant. Urea is consumed by the emission reduction system and is carried in an eight-gallon tank which is refilled through a port located next to the fuel tank filler. A full tank of the fluid lasts about 10,000 miles, so a refill coincides with the recommended service interval.
Driving the EcoDiesel equipped Grand Cherokee isn't much different than driving the Hemi model. Both have a comfortable ride, quiet cabin and plenty of power. The one exception is full throttle acceleration from 0 to 30 mph. The diesel's torque provides instant punch and gets there first, with the sound of fury and a feeling of authority.
All three Jeep Grand Cherokee engines are now attached to Chrysler's new eight-speed automatic transmission, which provides better fuel economy, quicker acceleration and smoother shifting. A secondary benefit for off-roaders is a lower crawl ratio of 44.1:1 when equipped with a two-speed transfer case.
The fully electronic eight-speed automatic features on-the-fly shift map changing, with manual shifting capability and electronic range selection using steering-wheel paddle controls. According to Jeep, more than 40 individual shift maps for specific conditions optimize shift quality and shift points for fuel economy, performance and drivability.
The intelligent software takes into account variables including engine torque gradients, kick-down events, longitudinal and lateral acceleration, grade changes, friction detection and downshift detection to determine the appropriate shift map. Additional parameters integrated into the control strategy include vehicle speed control, electronic stability control interaction and temperature.
The transmission efficiency and wide ratio spread provide the best possible fuel economy by operating at a lower engine rpm in both city and highway environments. Gear changes are nearly imperceptible due to the evenly spaced gear steps between each gear ratio.
Internally, the transmission has four gear sets and five clutch or brake shift elements. Only two shift elements are open at any time, so drag losses due to multiple parts rotating relative to each other are reduced, improving efficiency.
Since the new 8-speed transmission is standard equipment on all Grand Cherokee models, there is no added charge. The diesel engine costs $2,300 more than the 5.7-liter, meaning you can get into a diesel Grand Cherokee Limited for $41,290, including destination.
The fully loaded Summit we drove was $56,990 as tested. The Summit is a new top-of-the-line Grand Cherokee trim, positioned above the Laredo, Limited, and Overland. It let us sample the cabin that's the most posh and check out all of the Grand Cherokee’s new features.