Driving the Mopar Underground's Latest Dodge Ram Project in Moab

By John Stewart

Photos by John Stewart, Chrysler

Every year for the past few years, Mopar Performance has brought a brace of customized off-road vehicles to share with thousands of off-road enthusiasts that jam Moab, Utah, for the annual gathering known as Easter Jeep Safari. The engineers who build them like to call themselves the Mopar Underground.

Usually, Mopar Underground creations are proof-of-concept vehicles, having been built by enthusiastic Jeep and Mopar engineers to illustrate an idea or a plan in the works. Almost always, they are within a few months or a year of becoming available to enthusiasts in some way, shape or form. Vehicles such as the first-generation Dodge SRT4 are products of the Mopar Underground initiative.

Jim Sassorossi, director of Global Parts Sales and Marketing for Mopar Parts, told us the Mopar team gets valuable insights by talking to its core customers “about their unmet needs.”

“We’re also here to debut new off-road performance parts that are being considered for release,” he said.

Of the six custom vehicles that made the trip from Mopar headquarters this April, one in particular caught our eye. The engineers called it Big Red, a lifted Dodge Ram 1500 Quad Cab that had the latest in Mopar accessories and performance parts. Dodge allowed us to study, photograph and romp around in sand dunes near Moab with Big Red.

Big Red drives about the same as any new Ram 1500 equipped with relatively tall 3.55-to-1 rear axle gearing. In stock trim, the 5.7-liter Hemi V-8 is rated to produce 390 horsepower and 407 pounds-feet of torque. It’s likely Big Red's Hemi makes a little more top-end power, due to the cold air intake/dual cat-back exhaust modification. One thing is for sure — the truck really sings under full throttle, belting out a head-turning performance exhaust note. Our drive in the truck quickly attracted bystanders.

Full-size pickups are usually a little heavy to be considered natural dune runners. But in low range, and with a little momentum, we found ourselves ripping around bowls and powering up dune faces. As the dune surfaces got chewed up and the sand became loose, the value of the 4-inch suspension system and tires became apparent. It took more speed to stay on top of the choppy surfaces, but with 37-inch BFG 1250R20 tires and a longer shock, the more irregular surface dips were still absorbed by the suspension without undue bucking or bottoming.

The design of the suspension retains the best of the factory pieces, while adding clearance and damping control for taller tires. The hardware includes Bilstein monotube high-pressure gas replacement strut cylinders at the front to compensate for the heavier wheel/tire combination, and brackets that relocate the front control arms downward.

In the back, the four-link suspension becomes a clear performance advantage in off-road terrain, as it more easily travels from side to side and droops to keep tires on the ground. To add travel, the stock factory links are retained, but the attachment points are relocated using new brackets, and the coil springs are replaced with taller springs; no spring spacers are used.

Though there are always some tradeoffs when increasing tire size, steering effort and precision felt good for a full-size pickup. Front track width might be slightly increased due to the wider tires, but something very close to the factory turning radius is retained, and the suspension kit design seems to allow for good alignment. At Mopar's press conference in Moab, engineering manager Keith Montone said the new Mopar lift kits would be offered with a limited lifetime warranty.

The lift kit on this particular Ram 1500 requires a minimum of 18-inch wheels. The 37-by-12.5-inch tire size seemed about the maximum the suspension would support, and maybe a little more in terms of width. The setup allowed the tires to extend about an inch outboard of the wheel wells. That’s not a glaring problem, and it can easily be remedied by choosing a narrower tire or by adding fender flares. We noticed that the front fenders had been slightly trimmed for extra turning clearance, at the rear of the wheel well, but we had to look closely to see it. Beyond that, we didn’t see a lot of evidence that the tire had contacted the wheel well during use, which was surprising considering how heavily the suspension had been cycled during our dune running.

Another tradeoff that comes from taller tires has to do with gearing. By adding 37-inch tires, overall gearing gets taller, meaning there should be less available acceleration off the line, and highway cruising would move to a lower rpm. Our impression, with 3.55-to-1 rear ring and pinion and a 2.72-to-1 low range, is that the truck didn’t lack for power, even at an elevation of 5,000 feet. Throttle response seemed sufficient for all but the slowest trail work. Gears of 3.92-to-1 are available for those who plan to add taller tires and want the lowest gearing possible.

We didn’t get any time on the highway with the concept truck, but the five-speed automatic clearly has a low-enough 1st gear to get the 37s rolling. And we’ll wager that even with tires in that size range the 5.7-liter Hemi could still power the overdrive gear without hunting or downshifting, except maybe on the steepest highway passes. On flat ground, you’d probably see better highway mileage.

Other accessories included a tonneau cover for the bed and a front tow hook kit that attaches tow hooks to the frame. There's also a bed extender and a chrome bed gate. The transfer case is protected with a Mopar skid plate, and the hood has twin scoops.

Not all of Big Red's parts are shown on Mopar's website, but we were able to find many already listed in the current Mopar catalog.

Sassorossi told us that the Big Red concept is something Mopar dealers would be able to build for customers using all Mopar parts. According to product development manager P.T. Muldoon, more parts are coming online shortly as Mopar ramps up. “There will be another wave in Q2,” he told us.

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