When you think of Dodge Rams and Baja, you think of KORE. Ever since Kent Kroeker, the owner and founder of KORE, raced his stock Cummins-powered truck in the 2004 Baja 1000 to a podium finish and then drove the truck all the way back home from La Paz, the company has enjoyed the reputation of being not just Baja proven but Baja race proven.
Since then, imitators have popped up to offer similar products for the heavy-duty Dodge Ram, but none of them has the hard-earned pedigree of KORE. Last year, under Kent's guidance, KORE distributors raced three Cummins-diesel-powered Dodge Rams in the Baja 1000. Although only one finished on the podium, everyone on the KORE team gained valuable racing experience. This in turn enables them to better help KORE's customers with their own suspension systems. After all, it's not often a guy in Tennessee, New York, Los Angeles, or Canada can call his local dealer for advice and talk to someone who has actually competed on that equipment in the world's longest and most grueling nonstop off-road race.
I have known Kent since 1993 when we started Marine Corps Officer Candidate School together. While still on active duty, we spent many hours on motorcycles together, navigating the myriad trails on the Baja peninsula. I participated in a lot of motorcycle race efforts that took Kroeker to the podium many times. But it wasn't until a couple of years ago that I started driving trucks off-road. When he showed me the performance that his suspension was capable of, I was hooked. I soon had my own KORE Ram with an Unlimited Series kit and was loving every minute of it. Soon thereafter, he asked me to codrive for him in the 2006 Baja 500, and later that year I drove a section of the Baja 1000 for his Canadian distributor. Needless to say, I was very excited when Kent asked me to help him build and race a new KORE truck.
Little did I understand the monumental task that was at hand.
After last year's Baja 1000, Kent decided it was time for KORE to take the next step. Previously, Team KORE had been doing what Kent calls "adventure racing." For KORE, those days were now over. Bolting hardcore suspension systems to a heavy-duty hay-hauler so that it could withstand the punishment of Baja was satisfying and a good way to both prove and promote products for the consumer, but now it was time to not only finish... but to win.
Although the heavy-duty Ram is a great design, the Cummins Turbodiesel is one heavy motor. Kroeker decided that the next step would be to build a race truck out of the Hemi version of the Ram 2500. The Hemi will never replace the Cummins for someone who wants to tow heavy loads, but the weight savings of the Mopar V8 make it an attractive option for serious off-roading. Further weight would be saved by using a standard cab instead of a Quad Cab and keeping the cage design as simple as possible. With this design, we envisioned a weight savings of close to 2,000 pounds.
Finding a late-model standard cab HD wasn't as easy as first thought, but eventually KORE located one in Georgia. Kent drew up a strong but minimalist design for the rollcage then put the truck in the expert hands of Worthington Off Road, KORE's Los Angeles County distributor. Worthington Off Road uses CNC tube benders and the latest equipment so that after this cage was made, duplicate versions could follow without any painstaking R&D. Just put the tube in the machine and it comes out perfect - every time.
With any luck, we'd get the truck back in about three months or so. This would give us just enough time to complete the build before the Baja 500. In my mind, this was finally going to be the first year we'd go down to Baja completely prepared and not endure a lot of last-minute flailing.
Anybody who has ever actually raced in Baja is laughing right now.
We actually got the truck about nine weeks before the race, which in the world of custom fabrication is right on time! Needless to say, our work was cut out for us. As it would turn out, we spent every single day of that nine weeks working until the wee hours in order to complete the project on time.
The first day was pretty fun as we all reaffirmed our love with the plasma cutter and the Sawzall. After we had removed just about everything from the truck that wasn't absolutely necessary, the next step was to fabricate the rear structure of the cage. This would serve to stiffen and strengthen the frame as well as serve as the mounting point for the 3.5-inch Fox bypass shocks. In order to maximize the damping effect of the shocks, we located them as far outboard as possible by putting the lower shock mount directly over the custom Deaver leaf packs. We used all straight tubes and doubler plates to create a rear cage that was ultrastrong but still lightweight. It was often difficult to force ourselves not to overengineer the rear of the truck, and things sometimes devolved into a scene from American Chopper. Tolerances were very tight because the top of the shock cannot protrude above the bedside, nor can it be mounted too low or the shock body will hit the frame. Eventually, we got the geometry right with just enough metal and just the right angles to keep the rear end together and under control.
Once the bed cage was complete, it was time to install the fuel cell. Unlike many trucks that sink the cell behind the axle, we decided to locate ours immediately behind the cab. We wanted it close to the center of mass, so that handling characteristics would change as little as possible while the fuel burned down during the race. We tucked the fuel pump, filters, and regulator under the bed on the left framerail and plumbed it all with AN fittings and push-lock hose. We installed dual Optima YellowTop batteries in the bed and wired them in series through a cutoff switch to the main electrical buss in the cab. We've never had a flat while racing Toyos, so we opted for a single spare tire that we mounted horizontally in the bed with a simple spinner.
As per SCORE rules, we retained the stock dash but removed all panels that could potentially fly off during the race, including the glovebox. We initially left quite a bit of the stock dash components in place, but after our first test session a large panel wound up in the driver's lap during a particularly rough section and we were forced to adjust our definition of what could possibly fly off! We reinforced the plastic foundation behind the dash with steel gussets and installed trick gauges and marine-grade switches.
We used programmable gauges from Nordskog that allowed us to control big, red idiot lights, a feature that later proved to be invaluable during testing, prerunning, and in the race itself. Focusing on gauges when you're getting violently tossed around can be difficult, and those warning lights were just the ticket to focus our scan when needed. We used a RAM mount to locate the Lowrance GPS just above the gauges. Everything was laid out so that the codriver could easily navigate and monitor systems without having to look too far down in the cockpit and the driver could concentrate on driving. We reinforced the stock seat sliders and mounted MasterCraft Pro 4 racing seats. Then, we framed a center console to support the shifter and to provide a waterproof yet accessible mounting location for most of the electrical system. We then mounted the radio and Procomm intercom as well as the fresh-air pumpers for the drivers.
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.
Due to time constraints, we opted to forego fabricating a traditional Baja-style front bumper, so no nerfing anyone in this race. We went instead with a very burly lightbar from HRC, to which we mounted our four 8-inch La Paz HID lights from Baja Designs. We also picked up six of the smaller, but still very bright, Fuego HID lights, two of which were used to replace the stock foglights with the other four sunk into the front bumper.
So now the truck was ready to roll - time to turn hypothesis into theory and theory into a finish line!
Next month join KORE's Team Desert Assault for Hemi R&D at the Baja 500.
Years ago, when you looked into the wheel house of old-school race trucks, you could count on seeing a cluster of two to four small shocks between the wheels and the frame. Nowadays you usually see a shock to carry the coils and a shock to take the hits. On modern race trucks, it might be only one working shock - but she's a big shock. These massive shocks are 3 to 4 inches in diameter - serious dampers that carry a ton of oil, contain huge pistons, and develop tremendous amounts of hydraulic force.
So why the global shift from lots of small shocks to one big shock? Some of it comes down to technology. In the golden era of Baja racing, you saw the legends racing on a cluster of off-the-shelf yellow or white twin-tube shocks. Because they would fade and blow seals halfway through the race, these shocks often did little to isolate Parnelli from the "24-hour plane crash." Triple and quadruple redundancy was critical. Modern seal and bearing design has made racing shocks much more reliable performers. Unless the setup is incorrect, good shocks usually don't fail during races.
Most race trucks and cars are designed around the suspension. It's much easier to design a frame around one big shock versus four smaller shocks. At each wheel you only have two pivot points to worry about instead of eight. It also makes tuning a heck of a lot easier and more precise when you only have to adjust the valving or twist the tubes on one shock instead of four.
When designing the suspension on the KORE Hemi, we were very cognizant of the fact that it's easy to "over-shock" a race truck. You have to consider motion ratio, spring rate, wheel travel, gross weight, and speed. Too small a shock and you'll develop too much heat too quickly and damping will go away. Too large a shock and the suspension will feel sluggish and noncompliant, the tendency being to pack and tug on the rebound stroke, no matter how light the valving and how open the tubes.
Stock Full rules require stock suspension and steering parts as well as retention of all stock pivot points. The maximum wheel travel available is roughly 10 inches - not a whole lot considering the heinous nature of modern Baja racecourses. What used to be washboard 20 years ago has been pounded by 700hp Trophy Trucks and Unlimited Class 1 buggies into long sections of relentless 4-foot whoops. We needed a lot of shock in the front to tackle this kind of terrain. For us, the choice was clear: the massive Fox 4.3 - the biggest shock on the market.
Aside from their physically intimidating size, these shocks have some very innovative features. The first thing I like about these shocks is the fact that you can get them with a lot of bypass tubes - standard is three for compression and two for rebound. Aside from precise compression-tuning possibilities, having two rebound tubes allows you to run a physically heavier rebound stack, then open the shorter tube up more than the longer tube. It keeps the wheels loose and responsive in the midstroke while providing a little "hang-up" at full bump and a hydraulic "top-out" at full droop. And the giant size makes all the difference. Approaching full bump, these shocks generate so much force it's almost impossible to bottom the truck, except on stuff that knocks the wind out of codrivers.
Another thing that makes these shocks really special is their stainless steel pistons. Because of steel's strength, Fox can make its pistons much shorter than those made from aluminum. This is an advantage because it reduces the effects of pressure spike and some other undesirable characteristics as the piston passes bypass-tube orifices. Additionally, steel pistons expand and contract at the same rate as the steel shock body, so tolerances can be closer. Fox also uses what it calls an "energized" wear band. Underneath the piston's seal, there's a special Viton ring that puts constant pressure on the wear band to further ensure a total seal and maximum efficiency. With the special Fox fluid, the components in these shocks can perform at temperatures that would turn normal shock internals into useless mush.
For the rear of the Hemi, we went with Fox 3.5-inch shocks. The rear axle can stroke a full 14 inches of travel, so with more movement and a 1:1 motion ratio, we didn't need quite as much damping. I felt that the 4.3s out back wouldn't provide fast enough rebound. Fourteen-leaf race packs have a lot of internal friction as they slide against each other. On smaller bumps you almost don't need a shock, so you need a really loose rebound effect to prevent the rear from "packing up" - an enemy of traction. In our previous race trucks we used Fox 3.0s, which worked great. We just anticipated driving this truck a bit harder, so some more compression control was in order. During testing with the 3.5s, we found them to be superb. These shocks feature a unique "gold valve" (essentially a giant needle valve) and solid pistons, so you can externally adjust free bleed.
When we first started testing with these giant shocks, we discovered a new realm of performance. Our speed threshold opened up to new levels, literally double what we were doing before. We could mash right into bumps that would previously have had us crawling. We could now keep the truck pinned and get on top of the bumps we once called "rollers." A few days of tube tuning and spring-rate changing, and we doubled our speed again over some of the rougher sections.
It became apparent that the new limiting feature in the vehicle was the physical endurance of the codrivers. A Stock Full truck driven to the limit is no joyride: It takes a special person to sit in the right seat and get punished for hours on end. When I explained this to John Marking, head of the Fox Racing Division, he said, "Tell 'em to stop crying!"
"Sound advice," I thought.
While engineering this new truck, we took great pains to separate the ECU (motor's computer) from the TCU (transmission's computer). Normally all engine and transmission management is handled by the same computer. If something goes wrong with the transmission, a sensor then complains to the motor. Example: We start to lose Second gear in the transmission. The transmission then says to the motor, "I need to live! Give me no more than a sickly 100 hp and 2,500 rpm!"
Joe Consumer can then limp the truck to the dealer without a catastrophic failure. Conversely, Joe Racer doesn't care what his tranny "feels." He has a new transmission waiting at the next pit 50 miles away. All he cares about is winning. He wants to keep it pinned in First or Third gear at 5,600 rpm, 235 on the water temp, 220 on the tranny temp, make maximum speed to the pit and swap trannies there. That's why we used separate computers for both the tranny and the motor. The motor can't talk to the tranny and the tranny can't talk to the motor.
But, effective management requires a constant source of precise, real-time information. In aviation, monitoring systems isn't a question of winning or losing - it's a question of life or death. If your engine dies, you can't just pull over at 25,000 feet. More than half the KORE race team consists of Marine Corps combat pilots. These guys demand a lot of information to maintain their SA (situational awareness). We wanted to design the cockpit of the Hemi to provide maximum information in the clearest, most sophisticated format possible so that nothing gets by the codriver when he's task-saturated with navigating and communicating.
Our plan was to use good old analog gauges and idiot lights, but this wasn't as simple as it seemed. In the past, I had used all kinds of gauges: liquid-filled, fluid-damped, digital - you name it. These gauges all had shortcomings, from reliability to readability. Plus, the complexity of hooking up separate sensors for the idiot lights was a real pain.
We did some research and found a great American company called Nordskog. Bob "Ironman" Nordskog, an offshore racing legend and member of the Motorsports Hall of Fame, founded the company over 30 years ago. Nordskog offers full lines of both analog and digital gauges, including patented GPS-satellite-controlled speedometers that have no wires or cables as well as standard auxiliary gauges such as water temperature, oil pressure, fuel level, and voltage.
These gauges were just the ticket for us. They're made for the punishment of offshore racing, but we found that they were perfect for professional off-road use. They're sealed and weatherized, and pointer bounce is electronically eliminated. They're also made in the USA and have a lifetime warranty.
The best thing about these gauges is that they analyze and interpret as well as display information. Programmable output wires allow you to manage, not just monitor, the information. These output wires can be set to activate at any numerical value on the gauge. Then the signal can be used to turn on shift lights, fans, warning alarms, and for us: big, juicy, red idiot lights.
During the Baja 500, these gauges performed flawlessly, providing clear information as the situation dictated. Using their unique features, we programmed our idiot lights to illuminate as the motor and transmission temperatures or fuel and oil pressures reached their maximum or minimum values. These features proved invaluable during prerunning and racing.
*A fuel-pressure fluctuation revealed that we were running out of fuel earlier than anticipated. Black smoke indicated a rich condition that we resolved by replacing fouled O2 sensors, thereby bringing our range back into spec.
*An overvoltage indication led to a wiring problem that had resulted from small-gauge wire.
*Transmission overtemps were handled by reducing throttle position until our safe threshold could be maintained.
*High water temperatures were traced to blown radiator-fan fuses. This caused a separated hose. Precise monitoring during a low water condition permitted continuing despite the increased temperatures.
When you're racing all out, you're often running along the ragged edge of both human and mechanical performance. Without proper information for the humans to effectively interface with the machine, you can't operate at the limit. We found that the Nordskog gauges were absolutely essential in helping us accomplish our mission. These high-tech parts are going to be part of the KORE race program for a long time.