America’s Range Rover at its best, as added bonus, this JGC is a Mercedes-Benz derivative.
500 K Left 1
100 Square Right
350 Flat Into Crest Hairpin Left
50 Square Plus Left
800 Caution Jump Into Right 3 Tightens
1000 Straight Into K Right 5, Don’t Cut… Don’t lock Up…
Dom…dom…dom, an orange low tire pressure warning light flashes on the dash.
Blasting on the razor sharp gravel pavement at freeway speed in the driest, hottest and harshest environment on earth with temperature sizzling at 120 degree F, and miles-and-miles from civilization, the rear end sliding, countersteering recovery made me feel like I was the late Colin McRae in this brand new Jeep Grand Cherokee (JGC).
The fun lasted until I wished my portable navigator would offer the pacenotes like the co-driver in the pro-rally racing particularly the “Don’t Lock Up” one. A rear tire was punctured in the middle of the Death Valley dessert.
Pacenote Simply Defined
K=bend or kink; Square = 90 deg; Square Plus = less than 90 deg; Hairpin = 180 deg; 5 point scale = 1 gentle to 5 being 90 deg bends.
After numerous bloody hell remarks in imitated Scottish accent, a regular sedan that we brutally and humiliatingly overtook earlier, steadily drove pass and offered assistance. We then once again verbally blew off with the confidence that we had a full-sized spare in stow.
Until we lifted up the cargo floor liner, “#@*()*()#*$,” every cussing word was used in every existing language and might even included some from Cherokee Nation. We limped home like a dog with its tail between its legs, totally defeated on a donut. Sir Colin McRae might turn in his grave if he knew passenger tires and spare donut were fitted in America’s Range Rover!
The 2011 JGC and its ancestors in reality are crossover-utility-vehicles (CUV) instead of a sport utility vehicle (SUV) since they have never been underpinned by a frame commonly found under a horse wagon where their century old remnants are scattering all over the ghost towns in Death Valley. However, CUV and SUV are all intermixed nowadays. To us, JGC is Detroit’s Land Rover, we would prefer to refer it as a SUV. CUV is a SUV wannabe.
Jeep introduced the first Grand Cherokee [chassis code: ZJ] in 1992 North American International Auto Show in Detroit in response to the ever growing demand of the Sport-Utility-Vehicle era. This mid-size SUV was the invention of combining creature comforts and offroad capability into an unibody – similar to a passenger car – rather than its competitor’s essentially a station wagon on a pickup truck chassis. The second generation [WJ] came in 1999 further enhancing luxury and power. Its major enhancement came from the Uniframe construction to add strength to the body with help from Porsche. Both ZJ and WJ enjoyed successful sales where each generation reached over 1.4 million sales.
The third generation [WK] was released in 2005. It featured the much criticism from the offroading enthusiasts for the use of double-wishbone front and independent rear suspensions to promote on-road refinement. Due to the economic downturn, the total production volume declined to 650,000 units.
This 2011 Grand Cherokee is the fourth generation [WK2] of the model series. It was debuted in 2009 New York Auto Show and went on sale in summer 2010 as the 2011 model. The platform is co-developed with Mercedes-Benz and currently underpinning the Benz ML-Class SUV. In the form of the Grand Cherokee, the platform has 114.8-in wheelbase, length and body width at 189.8-in and 76.3-in, respectively. The cargo room has 35.1-cu.ft capacity and can be expanded to 68.7-cu.ft when the 60/40 rear seats are folded.
In 2010, the 2011MY Grand Cherokee came in three trim levels: Laredo(base), Limited, and Overland. Each level can be equipped with the optional 4WD system and a Mexico built 5.7L V-8 engine which generates 360 hp and 390 Ib-ft.
The tester in Brilliant Black – Crystal Pearl Coat paint is the Laredo 2WD model equipped with a 3.6L V6 engine and 30,995.00 MSPR. It is assembled at Chrysler’s Jefferson North Assembly Plant in Detroit, Michigan along side with its identical twin, 2011 Dodge Durango.
Engine – The spanking new Pentastar
The all new Chrysler Pentastar 3.6L V-6 engine consists of 24-valve DOHC aluminum head and block producing 290 hp @ 6,400 rpm and 260 Ib-ft of torque @ 4,800 rpm. It has 96 x 83 mm bore and stroke oversquare layout with 10.2:1 compression ratio. High and low end power is extracted and preserved from the use of variable camshaft timing on both intake and exhaust cams.
The air intake duct, manifold and valve covers are made out of composite material to save weight. Exhaust manifolds are integrated into the cylinder heads as part of the casting to improve refinement and further reduce weight by eliminating joints and flanges. Both intake and exhaust systems are tuned to maximize efficiency. Exhaust Gas Recirculation (EGR) is no longer needed to meet CA LEV II+ emission standard since the EGR effect is achieved by the independent cam phasing. Engine is flex-fuel capable which can run on fuel containing up to 85% ethanol. To reduce parasitic losses, the vane-type oil pump features electronically controlled variable displacement.
A closer inspection in the engine bay reveals the compact engine-size; it must be referred to as small block in Detroit’s lingo. The alternator and AC compressor are bolted rigidly to the stiff engine block which improves noise, vibration and harshness (NVH). Engine cover is lined with sound absorbent. Oil filter is a European inspired replaceable filter element (not the spin-on can type) and is conveniently located on top of the engine in the valley near the front.
The engine output is on par with its competitor’s similar displacement V-6 engines. The torque output is on the average side and peaks at the higher side of the rev range instead of the low end to suit for the nature of a truck. However, just realizing that the previously employed 3.7L V-6 PowerTech engine only had 210 hp and 235 Ib-ft output, this Pentastar is a major improvement considering the 80 hp and 25 Ib-ft increase in power.
This engine will be featured on 2011 Chrysler Corporate products from Grand Caravan to Challenger and will soon be used by Benz and Fiat. The base architecture of the engine can support the planned turbocharging and direct injection.
On the road, this Trenton, MI built engine is surprisingly smooth. When pushed to its 6,400 rpm redline, it emits that special solid engine note from the good old days of Detroit. None of that tin can, trashy pitches when Motown is underwater, moaning for money from your paychecks. There is no flat spot in the power range, as suggested by the 90% of peak torque is available from 1,600 to 6,400 rpm.
Transmission – Mercedes sourced
The Pentastar is mated to a Mercedes supplied 5-speed automatic transmission (code: W5A580) featuring Chrysler’s Electronic Range Select (ERS) manual mode, an adaptive electronic control that adapt to different road conditions and vehicle usage and the electronically-modulated torque converter clutch that can vary shifting speed and smoothness.
The W5A580, also known as the Mercedes 5G-TRONIC, is a straight carryover from WK. This transmission was first debuted in the Benz’s S-Class in the mid 1990s’ well before the DaimlerChrysler marriage. Despite its age and the newer seven-speed 7G-TRONIC transmission, the W5A580 is still popularly mated to Benz’s high output performance engines since it has a rated torque capacity of 796Ib-ft. A version of this transmission is currently employed in the Maybach and SLR McLaren.
The interaction of the ERS is a bit odd to operate. ERS is operable in the D (Drive) position by pulling the shifter toward the driver to engage ERS mode and to downshift. Upshift is done by pushing the shifter toward the passenger side. The head-scratching occurs when wanting to go back to auto mode. It has to be pushed all the way to the passenger side and hold for couple of seconds. In ERS mode, it will not auto upshift but will auto downshift.
This Munich and Detroit marriage powertrain combo has sufficient power to accelerate the 4,470 Ibs tester from dead stop to 60mph in low 8 seconds, and quarter mile comes low 16 seconds later. The transmission offers very Mercedes-like shifting feel. When cruising, the shifting is nice and smooth with slower engagement. When rushing, the engagement is quicker accompanied by never harsh nor shocking jerk – a good understanding with needs. Its adaptive nature also recognizes the demand of a lower gear like going up the long inclines coming out from the bottom of the northern hemisphere at -282 ft below sea level.
Cruising at 65 mph, the transmission is willing to hold a lower gear without sneaking back to 5th gear to keep EPA happy at its earliest chance. Throttle position is held without the need to keep on kicking down and no hunting for gear is experienced regardless how demanding the incline gets. Gear changes are at will with the throttle pedal. The communication is genuine you know exactly when it will shift. However, a common phenomenon is noted with the throttle mapping. To increase fuel economy, the trend for automakers is to build in a different throttle map for certain gears to dampen rapid throttle input. In the Grand Cherokee, this is obvious in the top gear. The throttle response feels lacking or delayed. A kickdown action is often necessary when further acceleration is required.
Other than the top gear, throttle input is natural and linear. It has the sixth sense thing about being part of the car even in a SUV. Gear ratio is kept relatively long from the use of 3.06:1 final drive ratio. The 1st gear can reach 50 mph and 80 mph in 2nd gear. In top gear, the engine revs at 1,800rpm at 65 mph.
On our 1,350 miles of test route from San Francisco Bay Area to Death Valley, California, we averaged 23.2 combined mpg versus EPAs city and highway MPG at 16 and 23, respectively and 18 mpg combined. Despite its low twenty MPG, the cruise range can easily be over 520 miles per tankful of unleaded regular, thanks to the rather large 24.6 gallon tank. Coefficient of drag is kept at 0.37 which enhanced fuel economy when compared to WK’s wind barrier like 0.40. To put it in perspective, the 2004 Mazda MX-5 sports car has Cd=0.37 also.