2006 Jeep Grand Cherokee Review

Specifications

Beating the Europeans at Their Own Game

DaimlerChryslers Street and Racing Technology (SRT) division is starting to get some serious kudos from automotive enthusiasts. While only a recent entry in the factory-backed performance scene in comparison to the likes of AMG, Quattro GmBH or SVT, in the few short years of its existence the three-lettered insignia has backed some of the hottest performers in their respective classes, such as the 2.0 SX-based SRT-4, the Crossfire SRT6, and of course, the almighty Viper and Ram SRT-10s. The objective is the same as Mopars own muscle machines from the 60s and 70s - total domination.

Even from SRTs early days, Chrysler Groups specialty brand has known no limits in terms of the vehicles it has tuned. The team has adapted to make the most of any Chrysler or Dodge product, regardless of its aspiration, number of cylinders, transmission or point of assembly. In its rapid expansion, much of the Chrysler and Dodge range has been covered, including the most recent conversions of the hottest large cars on the market - the Chrysler 300C SRT8, Dodge Magnum SRT8, and now the recently introduced Charger SRT8. But theres one problem that SRT has encountered on its quest: what to tune next? You may be surprised, but the answer is Jeep.

Jeep sport utility vehicles are known everywhere as some of the most capable off-roaders on the face of the planet. While the Wrangler upholds the traditional go-anywhere, do-anything image of the company, Jeeps other products, the Liberty and Grand Cherokee, have explored the more practical aspects of regular life as well as off-road functionality, bringing comfort and everyday usability to the masses, and in so doing, shaping what the modern sport utility vehicle is today.

But what happens when Trail-Rated meets SRT? You get the quickest, most powerful Jeep vehicle ever created - the ultimate on-road, all-weather Grand Cherokee SRT8. Having just made its world debut at the New York International Auto Show, the fastest Jeep ever made marks many other firsts for the SRT division, as its the first SRT-tuned Jeep and its the first four-wheel drive vehicle that the team has ever worked with. It was built and designed to strike right at the heart of the performance SUV segment, championed by the likes of the Mercedes-Benz ML55 AMG, BMW X5 4.8is and Porsche Cayenne Turbo. Feeling bullish about what the SRT team has developed, Jeff Bell, VP of Jeep commented, “The Jeep Grand Cherokee SRT8 . . . will leave in its dust competitors that cost twice the price.”

So, how does one go about building an American performance machine that will beat the Europeans at their own game? Dan Knott, Director of SRT says, “With an infusion of SRT DNA, the 2006 Jeep Grand Cherokee SRT8 is the new benchmark performance SUV. It has the raw power to outperform the Porsche Cayenne Turbo, while providing exceptional ride and handling, world-class braking, race-inspired interior appointments and functional, performance-oriented exterior enhancements.” It probably also didnt hurt to base it on Jeeps most capable and dynamic SUV to date.

Stuffed under the hood of the Grand Cherokee - and what makes Knotts claim of Cayenne Turbo-beating performance possible - is a specially-tuned 6.1-liter SRT HEMI V8 engine churning out a whopping 415-horsepower and 410 lb-ft of torque, an impressive 25 percent more power than the regular 5.7-liter HEMI V8 found in top-of-the-line Grand Cherokees. While not making quite as much power and torque as other 6.0-liter SRT8 offerings, the end result speaks for itself: an SUV that can rocket to 60 mph in less than five seconds, trumping all performance SUVs and a few serious sports cars to boot.

What enabled the base 5.7-liter V8 to produce 85 more horsepower was a complete reworking of the engines block and vital components. SRT engineers increased the bore of the cylinders by 3.5 mm to bump displacement up to 6.1 liters, and raised the compression ratio to 10.3:1, up from 9.6:1.

The tuned V8 also features new high-flow cylinder heads, freer-flowing intake and exhaust manifolds and a performance exhaust system, which allow the engine to breathe easier. To deal with the extra power, the block itself and many of the high-stress components such as the crankshaft, connecting rods and pistons were strengthened, while a heavy-duty oil pump keeps the vital supply of black gold constant at higher engine speeds.

To harness the massive power and torque from the big-block V8 engine, and to keep in line with Grand Cherokees all-weather reputation, the SRT team developed its first four-wheel-drivetrain. Like its motor, the SRT8 builds on the Grand Cherokees standard components, modifying parts to deal with the extra power.

The high-performance Grand Cherokee utilizes a hybrid transfer case, crafted from the front half of the lightweight Jeep transfer case, and then mated to the rear half of a heavy-duty unit. The latters rugged construction contains all the electronic components for the full-time four-wheel drive system. Along with a heavy-duty output shaft, the SRT8s unique transfer case has the capacity to handle the 410 lb-ft of torque, while weighing 60 pounds less than a stock heavy-duty transfer case. SRT has also upgraded the rear differential to a Dana 44 from the European Grand Cherokee turbodiesel, fitted with a larger ring gear.

To ensure a sporty, agile feel that counteracts understeer, the SRT team chose to give its Grand Cherokee rear bias by calibrating the permanent four-wheel drive system to send 90 to 95 percent of the power to the rear wheels under normal driving conditions. This configuration takes into account weight transfer, which is what allows the SRT8 to achieve its neck-snapping acceleration. Under towing or in slippery conditions, the system automatically adjusts the torque split to allow as much power as is needed to be directed to the front wheels. This advanced four-wheel drive system is yet another example of SRTs ability to make the most out of any vehicle it tunes.

With 6.1 liters of brute force and the added traction of four-wheel drive, its easy to see how this Jeep can out-muscle high-performance SUVs in a straight line, but not every road is straight. SRT hasnt put acceleration and quarter-mile times in front of other critical performance areas, namely handling and ride. Having executed the SRT-4 and the Crossfire SRT6, as well as all the new HEMI-powered SRT models, the team can confidently state that its Grand Cherokee can deliver and meet the expectations of its target audience.

Performance-tuned springs and dampers, new bushings and thick anti-roll bars provide the backbone for the GC SRT8s revamped suspension, reducing body roll and firming the ride. Front suspension knuckles with camber angle are also new and these components help to provide optimal contact between the sticky W-rated Goodyear rubber and the road.

The Grand Cherokee SRT8s ride height is roughly one inch lower than the regular model, contributing to its sporty looks, lower center of gravity and improved aerodynamics. Finally, the stock ESP stability control program has been reworked to interact with the improved dynamic capabilities, allowing drivers greater freedom before the system intervenes by cutting power and applying the wheel brakes.

On the outside, the Grand Cherokee SRT8 looks as good as it performs, thanks to a subtle body makeover. A new front fascia features an extra-wide intake to provide additional air-flow for the bigger engine, while integrated ducts help cool the uprated braking system. Jeep proudly offers four-piston Brembo brakes with black-painted calipers as standard on the SRT8. These powerful calipers clamp down on gigantic 14.2-inch discs in front, and 13.8-inch discs in the rear, allowing the big SUV to come to a stop from 60 mph in approximately 125 feet.

In back, the rear bumper has been reworked to include a center-mount exhaust system with dual four-inch chrome tips. Aside from offering body-colour door handles and grille, and the removal of the roof rack, the bodywork is nearly identical to that of regular models. The SRT8 rides on special chrome-plated five-star 20-inch wheels, which do a good job of filling up the SUVs angular wheel wells. Supercar-grade Goodyear Eagle RS-A runflat tires measuring 255/45WR20 up front and even wider 285/40WR20 in the rear provide the necessary grip to harness the SRT8s ponies.

The much-improved interior of the Grand Cherokee has been reworked by the SRT team to add sport to the existing luxury themes. Carbon fiber-like finish can be found on the instrument panel, shift knob and inserts on the leather-wrapped steering wheel, while the center console shifter-base and door trims receive satin aluminum appliqué. A full array of blue-accented SRT gauges, including tachometer, oil-pressure and a rather optimistic speedometer are all standard. The driver and front passenger sit in sculpted Medium Slate leather buckets, with grippy suede inserts, designed to hold occupants tight even during hard cornering.

As the range-topping model, the SRT8 comes fully equipped with climate control, heated power seats and a premium sound system.

Also, a host of technologies, once limited to high-end European luxury cars, will be available. The options list includes a voice-activated DVD navigation system, Satellite Radio, and Uconnect Bluetooth interactivity for true handsfree cellphone operation.

The first-ever SRT-tuned Jeep is a well-rounded package, balancing best-in-class performance with luxury and practicality, but the Grand Cherokee SRT8 brings even more to the game - value.

While many high performance SUVs start close to, or even into, the six-figure range, the new Jeep posts a price tag thats half of what one might expect to pay. While the actual figure hasnt been announced yet, it is expected to start at around $50,000 - expensive for a Jeep, but an absolute bargain when compared to BMW, Porsche and Mercedes-Benz counterparts. Expect the Grand Cherokee SRT8 to arrive in dealer showrooms by the end of summer.