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2007 Jeep Wrangler JK Unlimited - J 100 K

Posted in How To on December 1, 2009 Comment (0)
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Photographers: Kevin Wyas

Missouri 4Wheelers Supply, better known as 4WS.COM, is a major distributor of 4x4 parts and is known for its Jeep conversions. After a trip to the SEMA convention in Las Vegas in 2006 and being inspired by how the aftermarket had already embraced the new Jeep Wrangler JK, 4WS.com owner Kevin Wyas decided to get a JK of his own to show off a few of the parts his company offered. The plan was to keep it mild-at least that was the plan.

A quick flick of the throttle cleans out the Pit Bull Rocker tires during a climb up a waterfall.

In 2007, both the plan and engine changed. The JK was taken to the extreme with a new 6.1L SRT-8 Hemi mated to a 5-45RFE automatic transmission. In the process of installing the engine, Kevin designed and started production of ceramic coated headers for the swap, which negated the immediate need for suspension modification, dramatically decreased under-hood temperatures, and increased low end power. This combination resulted in roughly double the horsepower and torque of the stock engine. The guys at 4WS.com were also able to get the Hemi swap tuned and dynoed so that it would be perfect for customers upon pick up. Just having a Hemi was good enough for a while, but more drastic upgrades were still in the future.

To tolerate the power that the 6.1L Hemi put out and the heavy wheeling Kevin wanted to do, the drivetrain was upgraded. Front and rear high-pinion Dana 60s are filled with ARB Air Lockers, Superior Evolution axle shafts, Superior 5.38 ring and pinion gears, and Mile Marker locking hubs, making the axles extremely strong yet still streetable. Attached to the front axle is a steering assist ram from Howe and a custom high-steer setup to help point the big 42s in the right direction and still keep it street legal. Bolted to the pinions are 1350 CV shafts connecting to an Atlas II transfer case with 3.8 low range gears. The 3.8 ratio lets the Jeep crawl with the low end torque the engine and transmission combination turns out and still lets the Jeep get enough speed to haul through the open flats.

The front Dana 60 is kept in place using a Rubicon Express long-arm kit with 12-inch-travel Rock Krawler dual rate coil-over shocks. The front control arms were adjusted out to move the front axle 1 inch forward. In the rear, Kevin adapted the Black Diamond X2 leaf springs to move the rear axle back about 3 inches. Leaf springs were used in the rear to keep the Jeep more stable on and off-road and to handle heavy loads. So far, the leafs have been tested in Moab, Hot Springs, Arkansas, and Seymour, Missouri, with results that are even better than expected. The Jeep is completely stable and predicable and doesn't sag in the rear as much as it used to when loaded down. After moving the axles, the fenders needed to be modified to fit the 42s. Xenon flares were painted and bolted on the front. Rear flares were built on extended AEV corners and the rear fenders were cut out to match the new corners and flares.

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With all of the power and gearing, Kevin needed substantial traction. He put on a set of 42x15.0-17LT Pit Bull Rocker bias ply tires mounted on Raceline 17x9 Monster beadlocks. The tires have an aggressive tread design and siping that provides great traction in all conditions. Better yet, after two sets of tires, nearly 30,000 miles, and numerous off-road torture tests Kevin's never had a flat tire.

Keeping the Jeep's sheet metal safe from boulders are a selection of bumpers and skids. A custom front bumper sinks the Warn PowerPlant HP winch so air can still flow through the Griffin aluminum radiator. A modified M.O.R.E. rear bumper and tire carrier keeps the 150-pound tire and wheel combo in place. The Hanson rocker guards on both sides have prevented many trips to the body shop and provide a much needed step.

Just like the outside, the inside of the 4WS.com JK has been reworked to increase comfort and performance. Corbeau Special Edition suede-covered racing seats are mounted front and rear. The new front seat brackets were adapted to retain the stock air bag sensors. The rear seats were moved inboard to allow them to slide back past the wheel wells, maximizing leg room, and to give rear passengers a better view out the windshield. Between the front seats, the stock console was upgraded with a Tuffy center console insert for locking storage and a more comfortable arm rest. In the rear, a Tuffy drawer was installed to keep larger valuables safe and dry. To keep the Jeep on track and passengers entertained, the radio was replaced with a Pioneer DVD player and navigation unit with a Sirius tuner. An upgraded cage is in the works along with Crow five-point harnesses.

Kevin has driven his JK across the country several times for shows from Pennsylvania to California and wheeling at many events including the Moab Easter Jeep Safari and 4xAdventures in Hot Springs, Arkansas. The Jeep cruises along I-40 at high speeds (within the speed limit, of course) and still wheel on 4- and 5-rated trails.

On a recent trip Kevin hauled a 20-foot enclosed trailer with supplies for different events behind the Jeep for 4,000 miles with no problems. Instead he just got a lot of odd looks and thumbs ups.

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SPECIFICATIONS

Vehicle: 2007 Jeep Wrangler JK Unlimited
Owner: Kevin Wyas
Hometown: Springfield, Missouri
Engine: 6.1L SRT-8 Hemi
Induction: EFI
Transmission: 5-45RFE automatic transmission
Transfer case: Atlas II
Low range ratio: 3.8:1
Front end: High-pinion Dana 60
Rear end: High-pinion Dana 60
Ring and Pinion: 5.38
Front Differential: ARB Air Locker
Rear Differential: ARB Air Locker
Suspension: Rubicon Express long-arm front with Rock Krawler coil-overs, Black Diamond X2 leaf spring rear
Tires: 42x15.0-17LT Pit Bull Rocker bias ply
Wheels/Backspacing: 17x9 Raceline Monster beadlocks/4 inches

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