PHOTO 1 OF 8

2012 Jeep Wrangler

Long-awaited horsepower increase from new Pentastar V6 is a welcome upgrade for Jeep Wrangler lovers

by Tom Morr
Car Reviews - 2012 - autoMedia.com

First Drive: 2012 Jeep Wrangler — Jeep's placeholder powerplant is no more. The JK (2007-present) Wrangler's original motorvator, the Chrysler 3.8L V6 minivan engine, is officially an orphan. "What took so long?" Jeep purists ask. After all, the AMC-designed "PowerTech" 4.0L straight six serviceably powered more than 5 million Jeeps from 1987 to 2006. The 3.8L V6 seemed like a step down. Chrysler's challenges were meeting current emissions standards with a 1980s AMC design, and the fact that a lot of the 4.0L engine's tooling was worn out. The 3.8L V6—introduced in 1990 as the smaller-bored 3.3L for Chrysler minivans, New Yorker, Imperial, and Dodge Dynasty—was a longitudinally mounted Band-Aid fix.

JK-Generation Power

Lack of low-end power was the Jeep Wrangler's glaring deficiency. Entering the freeway in a stock JK often involved playing chicken with other vehicles. Mashing the skinny pedal didn't produce immediately felt results from the 215-hp engine. Heavy accessories such as oversized tires and a winch bogged down the 3.8 further. This created a cottage industry for Hemi V8 conversions. JK owners could get Chrysler V8 power in levels ranging from about 405 hp (5.7L Hemi) to 636 hp (7.2L Hemi)—installed turnkey for roughly the cost of a new Wrangler.

Although the long-awaited replacement engine has smaller displacement, the DOHC Pentastar 3.6-liter V6 is an all-around better match for the Jeep Wrangler. The engine was already in the new Grand Cherokee, so its appearance in the 2012 Jeep Wrangler wasn't a surprise.

VVT and Transmissions

Variable Valve Timing (VVT) helps make the all-aluminum Pentastar V6 engine both more powerful and efficient than its 90-pounds-heavier predecessor. Peak power is a 40-percent improvement at 285 hp, up from 202 horses. Although torque jumps only 10 percent from 237 to a maximum of 260 lb.-ft., the powerband is now more usable. The boxy, un-aerodynamic Jeep Wrangler gets up to speed much faster, with a three-second/25-pecent improvement in 0-60 mph time in the four-door Wrangler Unlimited: 8.4 seconds.

The 2012 Jeep Wrangler also received the same A580 5-speed automatic transmission found in the Grand Cherokee. A "lower" (numerically higher) 3.59 First gear contributes to standing-stop acceleration improvements and also bolsters off-road crawl-ability. Alternatively, the German-made NSG 370 six-speed manual transmission is available for those who want to attempt to achieve the maximum 21-mpg EPA-rated fuel economy. Off-road enthusiasts will likely also gravitate to the six-speed because of its 4.46:1 First gear ratio.

More Improvements

Fitting the new powertrain required some packaging innovations. Because 60 percent of Jeep Wranglers sold are four-door models, Jeep engineers prioritized family-friendly features. For one, the air-conditioning condenser is larger for better interior cooling. Engine cooling is improved with a larger electric fan. Because bigger and noisier go together, the fan uses pulse-width technology to vary its speed. Unlike electric fans that are either off or hummingly on, the new Jeep Wrangler fan adjusts speed and resulting sound based on cooling need.

In contrast to the minivan version of the Pentastar V6, the JK Jeep Wrangler's alternator is mounted on top. This helps give the Wrangler 30-inch water-fording capability. To balance exhaust scavenging, the driver's side has a "trumpet" curl to equal its length to the passenger's side crossover pipe.

Driving Impression

We spent a few hours' pavement time in the ultimate econo 2012 Jeep Wrangler: a two-door model with the six-speed manual and long-legged 3.21:1 axle gears. We initially searched for noticeable power improvements under 1,800 rpm in the barely broken-in test Jeep. The more standing-stop launches and low-rpm lugging we did, the more we adapted to the vehicle—and vice versa. With ESC (electronic stability control, aka traction control) engaged, the engine lugged down to 500 rpm in First gear without stalling. In other words, previous performance deficiencies are sufficiently solved. (The Hill-Start Assist feature also makes it harder to stall the manual transmission JK: This system maintains some brakeline pressure to keep the vehicle from rolling backward during clutch engagement.)

The Pentastar V6 really shines between 2,500 rpm and its 6,500 rpm redline. Backed by the six-speed manual, the 3.6's mid- and high-end had no perceptible flat spots. It continued to pull in proportion to accelerator input. The wide powerband rarely required downshifting to pass slower traffic at highway speeds. And on twisty two-lane country roads, the engine allows the driver to be as active or lazy as he/she wants with the stick. We threw down between Second and Third, playing F1-wannabe driver through the chicanes, then eventually settled into Second: no lugging and sputtering entering the curves, no high-pitching whining on the straights between turns. The engine note does have a turbo-ish hiss above about 4,500 rpm, but it's more of a get-it-done sound than a mechanical-cruelty shriek.

Off-Road Standard

Off-road, the 2012 Jeep Wrangler remains the industry's gold standard for off-the-lot capability. An off-road demo course was set up in Oregon's Tillamook Forest by the Jeep Jamboree crew, with a few purpose-built potholes and strategically placed logs. Only Rubicon models were permitted on this course. Rubicon configuration includes aftermarket-inspired locking differentials, an upgraded Dana 44 front axle (non-Rubicon models get the lighter-weight Dana 30), the 4.0:1 gear-reduction RockTrac NV242 transfer case, and electronically disconnectable front swaybars. 32-inch tires provide sufficient ground clearance for most places John Q. Wrangler owners would likely go.

2012 Jeep Wrangler Rubicon models are available with standard 3.73 axle gears (better fuel economy through less gear-reduction) or optional 4.10s. Our first whack at the off-road course in a 3.73/automatic Rubicon began as a cruise through the forest: With lockers on and swaybar disconnected, the driver basically just steers, occasionally applying the gas and brake as needed. One particular rutted sidehill section presented a challenge. Most testers (this one included) had to back two or more times and retry, even with professional spotting from the Jeep Jamboree staff. However, all Rubicons made it through under their own power.

To save face, a second pass in a 4.10/6-speed Rubicon was attempted. Having tried different lines the first time plus additional gear-reduction combined for off-road elegance the first time: up, through, and over with minimal tire-spin. The mechanical difference was a 73.14:1 crawl ratio (4.46 First x 4.0 transfer case x 4.10 axles) with the second Rubicon compared to the first one's 53.56:1 (3.59 First x 4.0 transfer case x 3.73 axles). In other words, the "lower"-geared Rubicon's engine crankshaft rotated more than 73 times for each complete axle rotation. Potential Jeep Wrangler Rubicon owners who want to add larger tires will definitely want the 4.10 Rubicon if they don't plan on doing other powertrain modifications.

Carryover Features, Interior, New Colors

The rest of the 2012 Jeep Wrangler is basically the same; firewall and tunnel tweaks were necessary to accommodate the new engine and automatic transmission. Also, shocks are upgraded to variable-valved Low Speed Tunable high-pressure nitrogen-charged monotube models for all but the base Sport model. These shocks are stiffer at slow speeds, softening on the highway to help cushion the bumps that are characteristically transferred into the passenger cabin with short-wheelbase/body-on-frame vehicles.

The new Jeep Wrangler's interior was upgraded for 2011. Sahara and Rubicon levels got softer, cushier materials; Sport models still have cost-effective plastics and vinyls. Optional color-matched fender flares and tops for Sahara models also debuted in 2011. Rubicon trim offers this "Euro" look for 2012. This Martha-Stewarting likely appeals to family buyers who might otherwise be looking at crossover SUVs or even sedans. Purists feel that black flares and black hard tops were signature "Jeepness" cues. The monochrome approach almost seems like a tribute to the Hummer H3.

Three new exterior colors join the palette for 2012: Dozer Yellow, Deep Molten Red and Crush Orange.

Conclusions

Jeep engineers successfully fixed the final Wrangler deficiency. Mechanically, we're hard-pressed to think of how the next generation will improve. The 2.8L VM diesel engine is already available in Wranglers overseas, and it or another diesel from the Fiat portfolio might appear in 2014, the rumored final model year before the next major Jeep Wrangler makeover. Off-road enthusiasts love diesel engines for their low-end power curve and generally superior fuel economy. However, Chrysler doesn't seem convinced that a diesel Wrangler's take-rate would be high: Many gas stations in the U.S. still don't offer diesel, and the additional cost of a diesel option often takes more than five years to recover in fuel savings. Are the people clamoring for a diesel Wrangler willing to actually pay a few more grand for it as well as higher-than-gas prices at the pump?

As it sits, the 2012 Jeep Wrangler should satisfy most vehicle-shoppers looking for an American icon to augment their active lifestyles. Chrysler maintained pricing on its volume-leader Sport models, beginning at an MSRP of $22,045 and ranging up to $24,245 for the best-selling configuration, Wrangler Sport with S Package (includes 17-inch wheels and air conditioning). Sahara and Rubicon jump about $300, topping out at a $33,570 MSRP for an Unlimited Rubicon. (Prices don't include $800 destination fee.) The sum of these changes could make 2012 the best sales year in the Wrangler's history. www.jeep.com