Pulling Forward: 2008 Jeep Grand Cherokee Limited 4x4 CRD
Diesel Technology for Jeep Could Show the Way
Diesels are on the march. You don't have to look any further than fuel prices to see this technology will become more attractive to new vehicle buyers as people begin to calculate the cost of fuel in a given year. Getting 20-, 30-, and possibly 40-percent-better fuel economy with a diesel engine will push many over the tipping point to buy their first engine without spark plugs. That's exactly what Jeep is hoping for. The program had some small delays, so the vehicles, originally due at the beginning of 2007, are making it into the marketplace by summer.
One of four engines offered in the Grand Cherokee (in addition to the 3.7 liter V 6, 4.7 liter V 8, and 5.7 liter V 8), the 3.0 liter V 6 uses the same Mercedes-Benz-sourced block and transmission as in the E Class sedan. However, the Jeep engine doesn't get all the available emissions technology M-B has developed under the Bluetec name, so the current Grand Cherokee diesel is only 43-state legal. Still, we're told the 50-state-legal version of the 3.0-liter V-6 turbodiesel will be in the Grand Cherokee in the next year or two, and that'll include most, if not all, of the emissions-scrubbing gear. This means we'll see some kind of particulate trap downstream in the exhaust--as well as the famous urea-injection system--to greatly reduce the nasty NOX emissions. Even without such coming technology, this diesel is impressive.
The 3.0-liter uses a high-pressure common-rail fuel-injection system that works at an incredible 29,000 psi with exceptionally smart Bosch solenoid injectors. Basically, these injectors spray and pulse fuel directly into the cylinder chamber with such precision and efficiency, the result is more power, better fuel economy, and a cleaner burn. In fact, in the Grand Cherokee EPA numbers are 20 in the city, and 25 on the highway. Power output is rated at 215 horses at 3800 rpm and 376 pound-feet of torque at 1600 rpm.
It's that last number that gets the towing crowd excited.
During our time behind the wheel, we loved that, as smooth as the setup is, it doesn't try to be something it's not--a dead-quiet gasoline engine. At idle, you can tell you have a diesel under the hood; at takeoff, the pull of the vehicle isn't earth shaking, as the 215 horsepower implies. Yet, once rolling and when you decide to put your foot into it, say for passing purposes, all the extra torque (maybe 100 pound-feet more when compared with an equivalent gas V-6) will put a smile on your face. Even at the track, it impressed our test crew, running a respectable 7.5 0 to-60 and 15.7 at 84 mph in the quarter mile.
Of course, no one's going to buy this vehicle as a race car, but with close to 400 pound-feet of torque, it'll be attractive to those midsize-SUV buyers who tow the occasional camper, boat, or toys. In fact, all that extra torque allowed Jeep to beef up its trailer rating, moving it from 5000 pounds with the gas V 8 to 7400 with the new turbodiesel. In addition, the M B-sourced five-speed transmission does a solid job of channeling the power through the gears with none of the harsh hits from the big torque numbers. The manumatic settings, where you can manually shift the automatic, also are able use multiple software algorithms to protect the gears from shifting too hard when it detects the vehicle is pulling a heavy load or is in low range (it is a Jeep, after all).
While we didn't get to take the Grand Cherokee out on a rough trail, you don't have to be a genius to realize that, when you combine the gearing advantage of a Jeep's transfer case with the huge low-end torque numbers of this engine, the available pulling power has no equal in its class. That said, we were a bit disappointed with the fuel-economy numbers we got. During our relatively easy freeway driving routes, putting several hundred miles between fill-ups, we barely hit 20 mpg. It would've been nice to have a sixth gear, because at 70 mph we were turning 2500 rpm. Our numbers would doubtless have been much better had we been patient enough to stay in the slow lane.
Our test unit came in Limited dress, which gave us all sorts of extras for a starting price of $38,340. Still, you can expect to pay a $3700 premium to get the 3.0-liter V-6 and five-speed automatic. The diesel will initially be offered only in Limited and Overland formats (average transaction prices will most likely be between $40K and $45K), but that may change as Jeep monitors demand. Look for other manufacturers to be watching Jeep closely as well, as GM and Ford have smaller V-6 and V-8 diesel programs available for their own midsize players.
There's great promise for the midsize-SUV segment to make huge diesel inroads for those looking for better fuel economy and more towing capacity. Is that a large sales number? Probably not (but we'd guess quite a few Truck Trend readers are in that group). Chrysler is predicting that, in the next 10 years, as much as 10 to 15 percent of the truck and SUV market could be diesel converts if that class is promoted properly. We say bring it on.
|2008 Jeep Grand Cherokee Limited 4x4 CRD|
|Location of final assembly||Detroit, Michigan|
|Body style||4-door SUV|
|EPA size class||Multi-purpose vehicle|
|Drivetrain layout||Front engine, 4WD|
|Airbags||Front, front side, side curtain|
|Engine type||72 V-6, alum block/heads|
|Bore x stroke, in||3.27x3.62|
|Valve gear||DOHC, 4 valves/cyl|
|Fuel injection||High-pressure direct|
|SAE horsepower, hp @ rpm||215 @ 3800|
|SAE torque, lb-ft @ rpm||376 @ 1600|
|Transmission type||W5J400 5-speed automatic|
|Final drive ratio||3.09:1|
|Indicated rpm @ 60 mph||2250|
|Crawl ratio (1st x axle gears x low range)||36.4:1|
|Track, f/r, in||62.0/62.0|
|Headroom, f/r, in||39.7/39.3|
|Legroom, f/r, in||41.7/35.5|
|Shoulder room, f/r, in||59.1/58.5|
|Cargo volume, behind 1st/2nd row, cu ft||67.4/34.5|
|Ground clearance, in||8.5|
|Approach/departure angle, deg||34.7/27.0|
|Base curb weight/as tested, lb||4663/4733|
|Weight distribution, f/r, %||54/46|
|Max payload capacity/as tested, lb||1050/1417|
|Max towing capacity, lb||7200|
|Fuel capacity, gal||21.1|
|Suspension, front/rear||IFS, double A-arm, coilover/liveaxle, coil/link, stabilizer bar|
|Steering type||Power rack-and-pinion|
|Turns, lock to lock||3.0|
|Turning diameter, ft||37.1|
|Brakes, front/rea||12.9-in vented disc/12.6-in disc, 4WABS|
|Wheels||17x7.5-inch cast alum|
|Tires||245/65R17 Goodyear Fortera|
|Quarter mile, sec @ mph||15.7 @ 83.5|
|Braking, 60-0, ft||145|
|EPA fuel economy, city/hwy, mpg||20/25|
|As-tested fuel economy, mpg||20.3|
|CO2 emissions, lb/mile||1.01|
|Price as tested||$42,730|