For those used to looking into the engine compartment of a Cummins-diesel-equipped Ram, the first thought that must go through one's mind when looking under the hood of KORE's truck is "Where is all the stuff?" Without the big diesel and associated intercoolers and other accessories, there is an enormous amount of room around the motor. Once we pulled out the air conditioner and heater, fuse box and battery trays, engine cooling fan and other components, you could practically run laps in there. We definitely had big plans for that space.
The first hurdle we had to jump was installing the massive 4.3-inch, five-bypass-tube Fox shocks. There simply isn't enough room under the spring buckets. Since all the stock suspension components must be retained for class rules, the only option was to create a shock with an extra-long shaft that could be mounted above the spring bucket. The location of the upper shock mounts was absolutely critical. Too high and the hood (which we can't change or cut) won't close. Too low and the bottom of the shock hits the spring bucket. And since the solid front axle moves not only back and forth but also side to side as it articulates through its 10 inches of travel, the shock must be located precisely or the shaft will hit the spring bucket and cause a failure. There was about 1/8 inch of slop in every direction if this setup was going to work, so we really had to be precise.
The next step was to get the drivetrain working properly. The stock motor is powerful, but its complex electronics, fail-safes, and limp modes were not appropriate for off-road racing. The 545RFE transmission is fully electronic, and the stock shift profile was unacceptable. For guys who are used to tweaking carburetors and distributors, all this electronic stuff seemed like a huge mountain to climb. The new computerized engines and transmissions are far more efficient for daily driving, but for professional racing they are a nightmare.
Fortunately, we hooked up with Powertrain Control Solutions (PCS) for the transmission and Squier Inc. for the motor harness. PCS supplied us with an aftermarket transmission controller and wiring harness. We sent the transmission harness to Squier who then integrated it with a scratch-built motor harness for the entire vehicle. This harness is a true plug-and-play masterpiece that included all the proper OE weatherized fittings.
Once we received the harness, it took us about an hour to route it and plug in all the connectors - including the ones for the transmission. Modules designed to mimic the output of the O2 sensors that we removed were included as well. All that was left was to hook up four unterminated wires and we were in business. The mighty Hemi roared to life on the first try.
Once the truck was driveable, we hit the local backroads and trails to test what we had so far. The transmission worked, but the performance wasn't yet where we needed it to be. We then made a few test runs with the laptop hooked up to the tranny computer and logged some data. After a few test sessions and working with the awesome guys at PCS, we soon developed a program that had the tranny shifting firmly and accurately. Basically, our program lets us tell the transmission in no uncertain terms what gear we want it to be in, much like using a tranny with a manual valve body.
It took the stock PCM a little while to adjust to the new setup, but eventually the motor ran OK. After we were able to reflash the computer with a new set of instructions, it really became a player, allowing us to create over 400 ponies. This is with no changes to the stock internal components. We changed the stock gear ratio from 3:73 to 4:56 courtesy of Jason Hughes at Hughes Racing Components (HRC). When combined with the 4:56 gears and the PCS tranny controller, we now felt confident that we had enough power and reliability to drive a 6,000-pound truck with 37-inch Toyo meats.