A Pair of 6.1 Hemi JK Wranglers, That Is
The Jeep JK Wrangler has taken the off-road-vehicle market by storm. Both the Wrangler (two-door) and Wrangler Unlimited (four-door) have been selling so well, Jeep can't keep up with the orders! We wanted to build a JK to take advantage of the new design and to use off-road. It was hard to decide whether to build a two-door Wrangler, which looks great in our opinion, or a four-door Wrangler Unlimited that, when we first saw one, looked to us like a Vegas limo company had added a pair of doors to the Jeep. It grew on us and now we really like the Unlimited, and apprently so do you, since 70 percent of all Wrangler orders are for the four-door.
We called Doc Murdoch at Dave Smith Motors, the largest Dodge Chrysler Jeep dealership in the world, and got a great price on an '07 Wrangler Unlimited Rubicon. Since the Wrangler is selling so well, Jeep was giving no deals to friends, family, or employees of DaimlerChrysler, so the great deal Doc gave us was even sweeter. We drove up to Kellogg, Idaho, where Dave Smith Motors takes up at least half the town, and picked up our new Rubicon.
Meanwhile, in Burnsville, Minnesota, Dan McKeag, owner of Burnsville Off Road, and the Burnsville crew, were busy making engine swaps work in the new JK. Whether it was a 2.8 diesel out of the Liberty, a 5.7 Hemi, or the very nice SRT 6.1 Hemi, Burnsville Off Road was putting them in the new JK Wrangler.
Dan told us that the Controller Area Network bus (CANbus) system used in the JK actually makes some aspects of the swaps easier, as the engine and vehicle communicate with each other. Tony Squire at Squire Incorporated in Mena, Arkansas, supplies his beautiful harnesses for the Burnsville JK swaps. Tony's harnesses look OE and use all factory connectors. Dan is able to flash the JK computers so everything works, including ABS, TCS, BAS, ERM, and ESP, the alphabet soup that makes up the Electronic Stability Program in the JK. The speedometer, cruise, air conditioning, and all other systems work just as they did when the JK rolled off the Jeep assembly line. All future engine swaps in new vehicles are going to have to deal with these systems. Burnsville Off Road has already done it.
We told Dan we still weren't excited about the Unlimited's four doors and he told us that was OK, as he was building a two-door Wrangler Rubicon and would trade us if we still didn't like the four-door at the end of the project. He also talked us into going with the 6.1 Hemi in ours, the same engine he was installing in his silver two-door. This was a hard sell, as the 425hp 6.1 is substantially more expensive than the 5.7 Hemi, being that it's hand-built in Chrysler's SRT plant and balanced, blueprinted, and installed in only the SRT8 Grand Cherokee in the Jeep line. There aren't very many of them out there. At one point, SRT was going to release 24 crate 6.1s and, if our information is correct, about half shipped to dealers before they decided to pull the plug and quit shipping them so the 6.1 would stay exclusive. Dan has searched the country and found most of these crate engines, buying them whenever he can. We decided to empty our pocketbook (JEEP = Just Empty Every Pocket) and go with the 6.1.
The 6.1 in the Grand Cherokee comes with a full-time, all-wheel-drive transfer case with its own bolt pattern, so this wouldn't do. We procured a 5-45RFE five-speed overdrive automatic used in other Hemi applications such as the Dodge Power Wagon. This computer-controlled transmission has proven itself for a number of years and will hold up to the use (abuse?) we plan on dishing out. The stock Rubicon Rock-Trac 4:1 transfer case we used bolts right up to this tranny, as will an Atlas or other T-cases you might want to use. Dan used the same transmission and transfer case in his two-door.
To install the engines in both Wranglers, Burnsville used its JK engine installation kit, which comes with everything needed to install the engine in the Wrangler. This includes the motor mounts, computer flashed for the engine/tranny/vehicle application, wiring harness, Howe Racing aluminum radiator, and all belts and hoses. The Burnsville kit makes it easy not only for the company to do a motor swap into Wranglers, but also makes it easy for a shop or do-it-yourself mechanic to perform the same swap.
The 6.1 shoehorns nicely into the engine bay of the JK using the SRT8 Grand Cherokee front dress. Burnsville keeps the factory cooling fan and shroud and mounts them on the big Howe radiator. We can report this keeps the big mill running cool, even crawling around in the desert when daytime temperatures reach triple-digit levels. Burnsville builds its own mandrel-bent, stainless exhaust system using stainless MagnaFlow mufflers.