Introduced in 2007, the four-door Jeep Wrangler Unlimited JK took the Jeep and off-road market by storm. What was previously only offered as a two-door with limited carrying capacity for potential buyers, was now offered in a full four-door configuration with much easier access for backseat passengers to get into the vehicle. Jeep listened to the market and created the JK which was now the ultimate four-door off-road vehicle for families to explore the great outdoors in.

Once released, the four-door JK featured an off-road-ready 116-inch wheelbase, which was a full 21-inches longer than the two-door version and only increased the overall length of the vehicle from 152.8-inches to 173.4-inches. With four-doors, a strong off-road ready wheelbase, a starting price of $21,000, and an overall length that still allowed the four-door to be very compliant in city and suburban environments, the JK Unlimited was a hit right out of the gate for off-road enthusiasts. Four-door Wrangler Unlimiteds were seen being owned by everyone from hardcore off-road enthusiasts, pop-culture icons, and even soccer mom “mall crawlers” that were sure to never even see a dirt road, much less the Rubicon trail – but that didn’t stop the aftermarket from exploding over the JK. 

Both two and four-door versions of the Wrangler were initially powered by a 3.8-liter V6 that, despite being a good motor, was underwhelming in the power department. In 2012 however, Jeep introduced the 3.8-liter’s replacement, a 3.6-liter Pentastar V6 that featured 285 hp and 265 lb-ft of torque, which was a welcome change. The new 3.6-liter Pentastar helped the stock Wrangler get around much easier thanks to its additional power and new technology. Nonetheless, off-roaders wanted more power and the aftermarket welcomed the challenge.

E-Force Meets Pentastar V6

For the past three years, the four-door Jeep Wrangler Unlimited has been the top utilized off-road vehicle for promotional and display purposes at the world famous SEMA Show which serves as the pulse of the aftermarket industry. With so many fully modded Wranglers to be seen at SEMA or even around your local off-road spot, it can be difficult for one to be really attention-grabbing.

Thankfully, through Off Road Xtreme‘s partnership with Edelbrock, we gained access to one awesome four-door Wrangler that not only stands out from the crowd in a tactful manner, but is packing some serious power thanks to Edelbrock’s E-Force supercharger system. To get the inside scoop on the build and also learn more about the E-Force system designed for the 3.6-liter Pentastar V6, we caught up with Eric Blakely, Director of Advertising for Edelbrock.

Off Road Xtreme: Thank’s for showing us this awesome JK build! What was Edelbrock’s main purpose of building this rig?

Eric Blakely: “Absolutely! Well, we wanted to have a vehicle that looked as good as our new E-Force system performs. We also needed a Jeep that we can use in advertisements and at events to showcase our E-Force supercharger. As part of the ongoing R&D process, we will be using the Jeep for testing the system in the same conditions and situations as our customers will be.” 

ORX: What goes into the process of determining which vehicles are a good fit for an E-Force kit?

EB: “We start by evaluating the market with our Sales and Executive teams to determine a deficiency in the market or the need for a complete solution that delivers the right combination of performance, value, and features. We also look for popular engine platforms that can easily support the added boost and make great power, over a long term, on the stock internals.”

ORX: So with the Wrangler’s 3.6-liter Pentastar being selected for an E-Force kit, what makes this particular system unique?

EB: “Well as you know, Wrangler owners love to modify their vehicles with larger tires, body armor, lifts, and accessories which despite looking cool, can really add weight that in turn makes a significant impact on performance – which creates a need for more power. The Jeep Pentastar E-Force is unique because it’s the first V6 application we have developed, as all of our previous applications have been for domestic V8 engines. It’s also the first engine to utilize our new universal design with the smaller Eaton 1320 series rotor assembly. This new design will allow us to quickly develop more supercharger systems for other smaller displacement applications.”

ORX: Who doesn’t like more power! What kind of testing is done before, during, and after the development of a new kit like this?

EB: “Well, we begin by casting a pilot run of a few superchargers that we can machine and install on the engine dyno to determine that our R&D will produce the power we expected. At that time we will also develop the initial tune that we will use to build the final drivability tune from, once the supercharger is in the vehicle. After everything is verified on the engine dyno, the supercharger is then installed in a vehicle to verify the kit components.” 

“At this point, the vehicle is then placed on the chassis dyno so we can develop the final tune that will be optimized for performance, drivability, and emissions legality. The Jeep will also be tested in various driving environments from typical street driving to off-road trails, including altitude, to ensure the calibration and supercharger will perform right in all of these driving conditions. Finally, we will have several of our executive team members drive the vehicle for several weeks to ensure the tune is good and there are no issues that may arise during various driving styles.”

ORX: Sounds like quite the process! What is it like driving an E-Force-equipped Wrangler?

EB: “With the E-Force, the Jeep now has more bottom end torque then before, which helps give it better drivability, especially when you throw in a larger wheel and tire package like we have – 37-inch tires are heavy! Bottom end drivability is always compromised on a truck or SUV when the wheels and tires are upgraded to a larger, more aggressive setup, so any power you can gain back just helps with low-end drivability. The E-Force also helps give the Jeep more towing power and torque when driving off-road.”

“We have been able to achieve increases over stock power by 96 hp and 61 lb-ft torque at the wheels; this is a 40-percent increase over stock and a far less expensive option than doing something like a V8 swap. When you drive a Jeep before and after an E-Force install, it won’t seem any different than a stock vehicle until you need it. The increased power at the low end is very noticeable and really helps get the vehicle moving by putting the power where you need it.”

ORX: That’s awesome, low end is definitely where the power is needed, especially for a Jeep that is going to do some crawling! One final question, who should or can install the E-Force kit?

EB: “Our supercharger kits include everything needed to install from start to finish and include very detailed instructions so customers can install them over a weekend with the right know-how. We recommend that the installation be done by a certified Edelbrock installer, dealer, or ASE certified mechanic in order to take advantage of our free Limited Powertrain Warranty, which covers the vehicle’s powertrain for 36,000 miles or three years.” 

The Rubicon Package

Serving as the pinnacle of the Jeep Wrangler platform, the Rubicon edition Unlimited was selected to serve as the baseline for Edelbrock’s project 4xFORCE build – and quite a baseline it is. Offered with standard equipment like Dana 44 front and rear axles, Tru-Lok differentials, electronic sway bar disconnects, hill descent control, and a host of other features, the Rubicon Unlimited is built with only one thing in mind – conquering the great outdoors.

With the Rubicon package comes some other nice little features here and there: like standard BFGoodrich Mud Terrain tires, Rubicon-specific wheels, Rubicon badging, and more to let passers-by know that the vehicle they are looking at is a trail-rated off-road machine. While the Rubicon Unlimited is nice enough in stock trim, the majority of owners that buy this vehicle want to up the capabilities right from the get-go with some aftermarket support.

Project 4xFORCE

As true off-road enthusiasts, Edelbrock had the same mentality as all of us off-road lovers when conquering the Rubicon build and wanted more out of the truck. Knowing the build was going to include larger off-road tires and wheels, Edelbrock started the build off right by upping the power output of the stock Rubicon with their E-Force supercharger kit.

Featuring a Gen VI Eaton 1320 TVS rotor assembly, the 3.6-liter Pentastar received quite the bump in power with 303 hp and 262 lb-ft of torque at the wheels. As Blakely explained above, a lot of time and effort went into the design and testing process of the E-Force kit in an effort to make the kit as easy to install and as powerful as possible for their customers, while still retaining low-end torque.

Project 4xFORCE in its natural habitat.

The boxes of parts sit ready to be added to the build.

Now that there was power on tap, it was time to make the best use of that power. Rancho Suspension was contacted to help give project 4xFORCE a facelift. Rancho’s front and rear bumpers were installed at 4 Wheel Parts in Redondo Beach, California to add needed protection from rocks, gain some approach/departure angle, and serve as a place to mount the Trail FX winch. In addition, Rancho’s Rockgear door sliders, cross over exhaust pipe kit, winch plate, front bumper light bar, and skid plates were all added to help protect the Jeep from the impending rocks it was sure to see.

Being fully armored-up, it was time to turn to the driveline. A set of 37-inch Nitto Trail Grappler tires were chosen to wrap the 17-inch Moto Metal M0971 wheels and give the Jeep some much-needed ground clearance and traction. As any off-roader knows, 37s require a lift, so once again, Rancho Suspension was contacted for their four-inch long arm lift kit combined with their RS7000 shocks on all four corners. Up front, a Rancho RS7000 steering stabilizer was added as well to help keep those 37s under control when the going gets rough.

With the wheel, tire, lift, and engine upgrade boxes all checked off, the attention turned to accessories. Rugged Ridge was contacted for a windshield light bar, three 13.5-inch LED lights, a vented hood, floor liners, A-pillar switch pod, and more. In addition, Edelbrock reached out to Bushwacker for one of their flat fender kits (p/n 10918-07), rear trail armor, and their side trail armor as well.

Next Steps

Project 4xFORCE currently sits with all of the aforementioned upgrades currently installed and has even had a sharp-looking graphics package added to help with the promotional nature of the build. Edelbrock has no intentions of resting on their laurels, however, and plans to upgrade to Dana 60 axles, add a Bestop Trektop Pro, and install a DynoMax Crawler exhaust kit in the near future to round out the build. 

As off-road enthusiasts and big fans of the Wrangler Unlimited, we really like the way this tastefully done 4xFORCE was built; as it sits, it is still extremely daily driver friendly which is a big plus in our eyes. At the end of the day, part of the fun of building a truck is showing it off, so why not design it with the ability to drive it to and from work while still having the capabilities to conquer the Rubicon trail?

All in all, it was a pleasure being able to be part of project 4xFORCE and being able to bring the build to our readers. If you are interested in staying up to date on the latest improvements of the build, check out Edelbrock’s “edelblog” blog page and be sure to stop by and say hello when you see this Jeep at a trail or show near you!