New engine improves Jeep Wrangler performance

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Jeep started out back in 1941 as a hard-riding barebones military vehicle, but it has come a long way since then. With lots of fine tuning, that first Jeep has evolved into the Wrangler with a carlike ride that retains the great off-road capability that made Jeep famous.

New for 2012, Wrangler is equipped with the Chrysler Group’s all-new 3.6-liter Pentastar V-6 engine that debuted in the Jeep Grand Cherokee last year. The new 285-horsepower engine significantly improves both on- and off-road performance with an 83 horsepower increase over the previous 3.8-liter V-6 engine. Torque also is up from 237 pound-feet to 260.

Even though the V-6 Pentastar is new, it has no high-tech features like direct injection or turbocharging. Instead, it relies on tried-and-true hardware like multipoint fuel injection and cam phasing systems that have been tweaked for maximum benefit.

Since Wrangler has a reputation as an off-road vehicle that can go anywhere, the alternator has been relocated near the top of the engine to achieve maximum water-fording capability.

A variable displacement pump adjusts oil flow rate and pressure to minimize the energy used to lubricate the engine. The upper and lower oil pan has been designed to keep the oil within reach of the pump when the vehicle operates on steep slopes.

Wrangler is available with either a six-speed manual or five-speed automatic transmission. Both are new to the Wrangler lineup, but have been around for a while in other Chrysler vehicles. Moving from four to five speeds improves fuel economy and helps reduce interior noise levels with reduced engine rpm at highway speeds. Closer ratios help improve shifting characteristics with smoother gear-to-gear changes.

Both the Sport and Sahara models include a Dana 30 front and Dana 44 rear axle. The two-speed Command-Trac transfer case includes a 2.72 low-range gear ratio. A Trac-Lok limited-slip differential is available for those needing more traction capability in environments such as sand, mud or snow. Also, a lower first gear ratio in the new automatic transmission gives the Wrangler more off-road capability with its lower overall crawl ratio.

The Rubicon model features heavy-duty Dana 44 front and rear axles and the Rock-Trac two-speed transfer case with a 4.0 low-range gear ratio. Rubicon also includes electric front and rear locking differentials, disconnecting front sway bar and 32-inch tires for the ultimate in capability. Prices for Wrangler models range from $22,045 for the Wrangler Sport to $29,820 for the Wrangler Rubicon.

Out on the open highway, we found the Wrangler to be comfortable and quiet. The new Pentastar V-6 is well-matched to the smooth-shifting five-speed automatic transmission. Accelerating from 0-to-60 mph takes only 8.4 seconds now, making passing and merging less worrisome. Driving with the six-speed manual transmission takes some practice to get consistently smooth shifts.

Off-road performance is just as one might expect from a Wrangler. Whether crawling over broken rocks or inching through slippery mud, the engine, transmission and suspension perform flawlessly.

Jeep completely reworked the Wrangler interior in 2011 to include upgraded materials, automatic temperature controls, heated seats, power mirrors and steering wheel controls for various systems. Other improvements included a USB port connected to the media center, 12-volt accessory outlets located throughout the Wrangler and a 115-volt AC outlet to power two-pronged home electronics.

Even with those improvements, getting into a Wrangler still requires a high step up and some bending and twisting to get into a front seat. Access to the rear seat is even more challenging. Comfortable seats help occupants endure even the worst of roads.

Jeep Wrangler’s signature features still include classic round headlamps, seven-slot grille, trapezoid wheel flares, removable doors, exposed hinges, a fold-down windshield and innovative removable and convertible tops and half-doors.