2007 Jeep Grand Cherokee Review

A Tale of Two Cherokees

I recently attended a Chrysler media event at which they introduced the all new Sebring, updates to the Chrysler Pacifica, and a wide range of vehicles to test on their Chelsea Proving Grounds Ride & Handling Course. As usual, I got entirely sidetracked. As much as I knew about the new diesel engine being fitted to the Jeep Grand Cherokee, I had no idea that it would be there, and be ready for a full road and off-road test. It was, and I got so excited that I pretty much forgot all about the Sebring. Some might say that a new Sebring would be entirely forgettable no matter how it was presented, although the new one is more interesting than the last, but when it gets introduced alongside a product as impressive as the GC with a common-rail diesel (CRD) sourced from Chryslers European cousin Mercedes-Benz (the Euros are light years ahead of us when it comes to oil-burning passenger vehicles), well the Chrysler four-door pretty much washed right through the synapses and left a vague, muddled image of Nissan meets Crossfire Sedan.

Enough about the Sebring, though, because as I just mentioned, the Jeep Grand Cherokee was possibly the most revelatory experience of the day, and that is no short order since I also had the chance to drive almost the entire line of SRT products, including my first ever chance to drive a Viper. Yeah, the Viper is cool, and a pretty good race car, too, but the limitations of the autocross and lack of access to a long straight meant I couldnt explore its massive V10 powerplant and all 500 of its horsepower, and, of course, anything close to its top speed, which would have been a surreal enough experience to leave a burning Viper logo seared into my brain and likely visible through my eyes.

Rather, my mind keeps returning to the short off-road course, and the approach roads I sampled and the incredibly smooth, torquey engine that grappled and grunted its way through a smattering of typical obstacles courtesy of the convenient, though rather abbreviated Lyman Trail. Furthermore, on my way back to the starting point, I had a chance to stop it, rev it, and launch it as well as run the usual gamut of city maneuvers. There is so little to separate it from a standard gas-powered Grand Cherokee once underway, from ride and handling to noise, vibration and harshness, and it would even keep up with the Hemi-powered edition in typical non-racetrack traffic. The guttural diesel rumble gave no evidence of knocking or shaking or belching big black clouds of smoke, but it still managed to produce a hefty 376 lb-ft of torque from its modest 215-horsepower 3.0L V6.  I would have said that it has massive and spine-adjusting acceleration if I hadnt also experienced my first ride in a Jeep Grand Cherokee SRT-8 only hours later. When I had the chance, I pulled the SRT-8 to a dead stop on a long straightaway, built up my anticipation by waiting for a couple of seconds, took a deep breath and then jammed my right foot down onto the accelerator as hard as I could and enjoyed the range of clichés washing over me as it spit out 100 miles an hour within a few short seconds. Thats right, 100. Normally I would measure its acceleration to 60 mph, but that was gone so fast that I didnt even notice it hit that mark. The only way I can describe it without sounding cheesy is to say it felt like somebody tossed a medicine ball the size of a sofa right at my chest.  No other car I drove that day equaled the GC SRT-8s slap-you-in-the-face-and-call-you-its-b!t(h straight line performance.

Once again, I didnt have a chance to do the same thing with a Viper, so there is room for re-education, and of course, if Bugatti or NASA wants to call me up and show me what real acceleration feels like, Id be happy to oblige, but until then, Ill have to let the GC SRT-8 reign as my personal pimp-daddy of acceleration. Im almost inclined to say that it shouldnt be legal because God only knows what kind of behaviour that kind of performance might induce from me if I were ever asked to drive it in traffic. The kind of acceleration developed from its 6.1L Hemi is, perhaps, too much temptation for one as adrenalin craving as I am.

Why am I going on and on about the SRT-8 GC when this review is about the upcoming diesel variant? Well, I had to tell somebody… but it also serves as an example of what the CRD is not. It is not a mind-blowingly fast monster ute, nor is it a cone-carving madman hell-bent on rewriting the asphalt with stories of rubber burned and lost. However, it can ford you through 4-foot deep puddles (more like a pond Id say), up ridiculously steep steps and over logs and obstacles that are standard fare for the worlds most authentic off-roading brand–yup, this one is Trail Rated, and then some.

It also offers a luxurious and hospitable cabin, with all the usual Jeep Grand Cherokee style and amenities, including climate control, wood trim, beautiful cream-coloured leather seating, steering wheel audio controls and even a nav system. Luxury Trail Rated is more appropriate. But what makes this vehicle valid luxury transportation is not the features or even a well balanced ride that straddles the comfort line on rough, even blasted roads and also manages to deliver great high-speed stability and excellent turning manners–its no SRT-8, but its easily the equal of many outright road-biased SUVs and also the luxury SUVs against which it naturally competes. Furthermore, the in-cabin noise is a muted blur, with the engine delivering its own unique character that has the same merits of a smooth-running V8. Never mind noise issues–I liked the way this engine sounded, a little gruff, but in a good way, and a subtle reminder of the intense power available from under the hood. 

All that power has to come from somewhere, and now its time to talk about the Mercedes-built 3.0-liter Common-Rail Diesel, originally designed for the Mercedes-Benz Groups luxury sedans and SUVs, and now making its first appearance in a Chrysler Group product in North America. This V6 promises efficient, uncompromised power with an expected 30 percent improvement in fuel economy over an equivalent gas-powered engine. Its one of the first new-generation European diesels to hit North America, combining technologies like high-pressure piezo injectors, four valves per cylinder with dual overhead cams and two camshafts per cylinder, intake-port swirl control and variable geometry turbochargers. 

Normally I wouldnt really understand what those things do, but I actually read the press release, so I can partially explain a couple of the more groundbreaking aspects of this diesel engine. As we all know (sorta) diesels work by forcing fuel into the piston chamber at extremely high compression (often double that of a gas-burning engine), and combustion occurs when it reaches an ignition point because there is a glow plug, which is like a spark plug but it is always on but really faint. Piezo injectors spray fuel into the chamber in superfine mist, and they operate more quickly than previous injection systems, with five injections per power stroke and pressure up to 24,000 psi. Thats a lot, by the way. The air intake governed by electrically controlled swirl valves that change the turbulence of the air going into the cylinders, optimizing the combustion process, meaning more of the fuel going into the cylinder is burned cleanly and less dirty crap gets spat out of the exhaust. Of course, even the exhaust gases are put to good use with a turbocharger that takes the high-speed gases leaving the cylinders and forcing them through a fan that is connected to a fan in the air intake that forces the air into the combustion chamber at really high pressure. Whats tricked out about this turbocharger is that the blades on the fan can kinda twist, so that when the engine is working at low speeds, it catches more of the exhaust and spins harder, but then at high engine speeds, the blades twist back to a more normal open angle and work with greater efficiency. The result is more boost and more power at low, low speeds, like when you just roll off the line or are slowly pulling up a steep hill, but you dont force the engine to work too hard when youre just rolling downhill or cruising down the highway. 

I apologize, but all that technical stuff is making my head hurt, although I hope it makes a bit of sense. If you dont really care how things work, just that they do, well, then youre like me most of the time, but with more biodiesel (diesel fuel developed from organic sources like sugar cane or corn or dead cats–no joke, some scientist in Germany actually claimed he could develop biodiesel from dead cats–not that he, nor I for that matter, was suggesting that you go out and start a cat farm to solve the worlds burgeoning energy crisis) becoming available in North America, diesel becoming cleaner every year, and diesel engines running cleaner as well, diesel power can help ease the transition to more earth-friendly fuel sources. You get similar gains in fuel economy as a hybrid (although emissions remain rather high), with a much more proven technology, and for the most part diesel engines also have legendary durability, which is why big rigs and industrial transports use the technology. Oddly, the Feds have adopted extreme, draconian regulations on clean-burning passenger diesels while continuing to allow industrial use of dirty, dirty fuel and engines, but the GC CRD is one of the first to meet those higher standards with the use of cleaner, low-sulphur diesel fuel mandated by North American governments.

Its all very complicated and typically bureaucratic, but Jeep is leading the way to a broader spectrum of energy technologies to suit different peoples needs and lifestyles. While a Toyota Yaris still leaves a smaller ecological footprint, the Jeep Grand Cherokee CRD can take your footprints to some pretty wild and crazy places on this planet while burning less fuel along the way than your average midsize SUV with that kind of pull. Its a new generation for diesel, but its still the same old Jeep.