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2012 Weekender Jeep Wrangler Part 1

Building Blocks

By Sean P. Holman

The ’12 Wrangler has proven to be one of the most successful products in Jeep’s portfolio with production at capacity and a pace to build 120,000 units for the ’12 model year. Aiding the Wrangler’s popularity is a brand-new drivetrain that includes the powerful and efficient Pentastar 3.6L V-6 and a new five-speed automatic transmission option. While these upgrades make for great performance in the stock world, what does it mean for modifications?

To understand more about how the changes made to the ’12 Wrangler will affect modifications, we picked up a manual-equipped Unlimited Sahara model with the idea of doing a real-world buildup that might be accomplished by a typical reader. The thought was to build this Jeep in a way that it would retain family-hauler functionality, but would remain as capable as one would ever need for off-highway excursions on the weekend.

So why did we choose a Sahara instead of a Rubicon? The Rubicon, out of the box, is an incredible vehicle. In stock form it has won our respect and our Four Wheeler of the Year award. However, we were on a budget, and we felt the extra $2,825 the Rubicon package cost over the Sahara was better spent on other parts of the build. We looked at the major features that make up a Rubicon (wheel and tire package, rock rails, electronic disconnecting sway bar, front Dana 44, electric lockers, and 4:1 transfer case) and decided that we would be altering or replacing each of those parts to better suit our needs, except for the transfer case. Because of the terrain the Jeep would be traversing, mostly wide-open desert, sand, and washes in and around Southern California, we preferred the 2.72:1 transfer case for this particular build. In most trail situations that don’t involve crawling, we’ve found that the Rock-Trac ’case of the Rubicon is geared a bit too low and in most situations that do involve crawling, the 2.72:1 T-case is adequate, especially with the manual transmission and its super-low First gear.

We decided on 35-spline RCV axleshafts and an ARB Air Locker for our front axle. ARB provided everything needed to load up our front Dana 44 with its locker.
We decided on 35-spline RCV axleshafts and an ARB Air Locker for our front axle. ARB provi

One of the biggest changes we planned for this Jeep was the installation of a Dana 44 front axle to replace the stock Dana 30. To keep our costs in check we decided to start with a stock Rubicon axlehousing, as opposed to buying a custom-built front axle. We ordered the Rubicon housing from J.T.’s Parts & Accessories in Cashmere, Washington, and after discussing our needs for the build, we settled on Nitro gears with an ARB Air Locker. J.T.’s was able to supply the parts and assemble the front axle, complete with sleeves and gussets, ahead of time, making for a less labor-intensive install down the road.

Because of the newfound power of the Pentastar, mixed with a slight gearing change in the manual (a 0.797 Sixth gear versus 0.84 before) and the wider gear ratio spread of the new W5A580 five-speed means that all former gearing strategies can go out the window. For manual transmission models, it used to be common that 37-inch tires required 5.13 gears. We chose 4.88s and are quite pleased. Not only is there much more power than with our ’07 Wrangler Unlimited (which has 5.13s and 37s), but we spin at a lower RPM on the highway. With this setup, our crawl ratio works out to be a competent 59:1, matching the stock automatic Rubicon’s ratio, but not quite as deep as the 73:1 of a stock manual Rubicon. If we were running 35s, 4.56s would have been our choice with a stick. As a general rule of thumb for the ’12 automatic, we’d recommend 4.56s with 35s and 4.88s with 37s. Of course other factors should be considered, such as the hilliness of the area you drive, as well as your typical cruising speed, altitude, and weight of vehicle.

Our plans also included front and rear Air Lockers, a compressor, lights, and a CB radio, so we installed an sPOD power distribution system. The sPOD is a high-quality product that adds six auxiliary switches and keeps all of your accessory power separate from your factory wiring. Once installed, accessories can be easily wired to the Source distribution box under the hood for safe, clean power, eliminating a rat’s nest of wiring and unnecessary holes in your firewall. For those planning on running lots of electrical accessories, the sPOD is a must-have upgrade.

At the end of the build, we hope to achieve a Wrangler that maintains or improves comfort, capability, functionality, and reliability. With those thoughts in mind, we went to work revamping our brand-new Wrangler. In this first installment, we’ll cover some of the foundation products for our build, before getting into the bigger changes next month.

  • We chose J.T.’s in-house Nitro brand for our ring and pinion gearset and we went with a 4.88 ratio. The ring gear has a dual pattern drilled in to the back so it is compatible with early and late-model JKs.
    We chose J.T.’s in-house Nitro brand for our ring and pinion gearset and we went with a 4.
  • One of the changes we requested on our Dana 44 was for J.T.’s to swap out the factory flange-style yoke for a traditional 1350 Spicer yoke.
    One of the changes we requested on our Dana 44 was for J.T.’s to swap out the factory flan
  • Once the gears were set up, the pattern was checked to ensure the gearset would run smooth and quiet.
    Once the gears were set up, the pattern was checked to ensure the gearset would run smooth
  • Here you can see the Air Locker and ring gear in place, as well as the routing of the Air Locker’s air line. J.T.’s checked the Air Locker operation on the bench before sealing the diff with the cover.
    Here you can see the Air Locker and ring gear in place, as well as the routing of the Air
  • J.T.’s Parts & Accessories stocks factory Rubicon housings and has the ability to ship them, built or not, all over the world. Here is our finished axle before it was packed up and shipped out to us. Note the thick-face Nitro aluminum diff cover and gusseted “C”s.
    J.T.’s Parts & Accessories stocks factory Rubicon housings and has the ability to ship
  • While our axle was busy being built up in Washington at J.T.’s, we went to work installing the sPOD power distribution system back at home.
    While our axle was busy being built up in Washington at J.T.’s, we went to work installing
  • First we removed the windshield header trim and installed the sPod mounting bracket.
  • Next, we reinstalled the header trim and tucked the switch panel wiring loom behind it. We then plugged the switch panel into the wiring harness, and screwed it to the mounting bracket.
    Next, we reinstalled the header trim and tucked the switch panel wiring loom behind it. We
  • The other end of the loom is routed down the driver’s A-pillar and through the firewall. The sPod kit even includes a new firewall grommet to accommodate the sPod wiring harness.
    The other end of the loom is routed down the driver’s A-pillar and through the firewall. T
  • At the heart of the sPOD system is the Source box, which mounts to the factory computer with a supplied bracket. Each of the six circuits is independent with its own relay, fuse, and diode and power comes directly from the battery. To add accessories, all you have to do is connect your positive and negative power leads directly to the terminal block located on the Source.
    At the heart of the sPOD system is the Source box, which mounts to the factory computer wi
  • One of the options with the sPOD system is the low voltage cutoff (LVCO) for battery protection. The LVCO will prevent a dead battery when a switch is left on, leaving the user with enough juice to start the rig.
    One of the options with the sPOD system is the low voltage cutoff (LVCO) for battery prote
  • For 2012 the JK switched from a Group 34 battery to a Group 91 battery with the spec of 600 cranking amps (CA) and 475 cold cranking amps (CCA), but we swapped our stocker out with a Group D34/77 dual-post Optima YellowTop with 870 CA and 700 CCA. We prefer the YellowTop for high draw applications because it is a deep cycle battery, yet has enough power to be an everyday starting battery.
    For 2012 the JK switched from a Group 34 battery to a Group 91 battery with the spec of 60
  • Our next task was finding a suitable mounting location for our ARB compressor. We were able to make some minor modifications to our compressor and mount it using One Off Fabrication’s short ’07-’11 Wrangler compressor mounting bracket. One Off Fabrication has a ’12-specific bracket on the way to make installation even easier.
    Our next task was finding a suitable mounting location for our ARB compressor. We were abl
  • The compressor bracket mounts to the two brake master cylinder mounting bolts and we had to clock the compressor to clear the A/C line running along the driver’s side of the engine.
    The compressor bracket mounts to the two brake master cylinder mounting bolts and we had t
  • With the wider Pentastar engine residing under the hood, we found space in the ’12 Wrangler to be at a premium, however we were able to fit all of the upgrades while keeping the engine compartment uncluttered. The only question remaining for us is the reduced battery space, potentially nixing the ability to run dual batteries in the future.
    With the wider Pentastar engine residing under the hood, we found space in the ’12 Wrangle
SOURCES
RCV Performance
611 Beacon Street
Loves Park
IL  61111
815-877-7473
www.rcvperformance.com
ARB USA
720 SW 34th Street
Renton
WA  98057
866-293-9078
www.arbusa.com
Optima Batteries, Inc.
5757 N. Green Bay Ave.
Milwaukee
WI  53209
8-88/-867-8462
www.optimabatteries.com
J.T.’s Parts and Accessories
866-349-6801
www.justdifferentials.com
sPOD
661-755-8139
www.4x4s-pod.com
One Off Fabrication
810-955-8000
www.oneofffabrication.com
By Sean P. Holman
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