The evolution of XDP’S Cumminspowered monster truck
Whether it be through truck-pulling, drag racing, monster trucks or any other form of motorsport, compression ignition lovers have always been willing to do whatever possible to push diesel performance into the mainstream.
Surprisingly, things weren’t always that way for Dave Radzierez, driver of the XDP monster truck. Long before he was into hot-rodding diesels, he worked them every day in the excavating business but otherwise avoided the stinky, noisy oil-burners in any of his personal vehicles. Nevertheless, as fate would have it, he found himself driving a loner 12-valve while his V-10 Dodge dually was in the shop back in the late 1990s.
At that point, everything changed. He immediately traded up for a diesel and, two years later, upgraded injectors, added a larger turbo, installed an exhaust and made 424 hp on a local chassis dyno—a big number in 1998.
Pulling Truck to Monster Truck
From there, tinkering with diesels progressed to Dave helping friends and acquaintances set up their trucks to sled pull, followed by him building a game-changing truck of his
own: the first center-drive, tilt-body Super Stock puller in the modern era. He called it “How Do You Like Me Now?”
After running the idea of building a diesel monster truck by the vice president of Flowmaster (one of the sponsors behind his Super Stock pulling effort), a deal was struck just six months later. In 2008, Dave debuted the first diesel-powered monster truck the industry had seen in years—and the first 5.9L-powered version ever. The compound-turbo’d, P-pumped 24-valve was dropped into a Race Source chassis, wore Hushpower lettering on both doors to promote the self-titled muffler line and was a huge hit at shows.
New Sponsor, New Truck, New Heights
After making the rounds on the monster truck circuit for a couple years, the truck excelled in free-style competitions, was well-received by other drivers—and the fan-base absolutely loved it.
At this point, XDP showed interest in becoming more involved in Dave’s diesel monster truck program and eventually
became the truck’s title sponsor.
With XDP’S full backing in 2011, things got downright serious. An entirely new chassis was built by Patrick Enterprises Inc., a fresh 12-valve Cummins from Mass Diesel went in, the Dodge body was ditched in favor of a 2010 Ford F-250 and the unveiling occurred on arguably the biggest stage possible—the SEMA Show. It was the beginning of a longstanding partnership between Dave and XDP, which still exists today.
First Backflip
With the state-of-the-art chassis, the new powerplant capable of 1,500 hp and Dave constantly improving behind the wheel, XDP pushed the truck’s capabilities forward in leaps and bounds. Already the freestyle favorite in many venues, Dave and team decided to give fans something more to cheer for in May 2014. In front of a packed grandstand and overflowing bleachers at the 4Wheel Jamboree in Lima, Ohio, Dave successfully performed his first backflip in the truck—the first ever for a diesel-equipped monster truck. In his two subsequent attempts of this feat, he stuck both landings flawlessly, along with two more under alcohol power.
XDP Version 2.0
Fast forward to 2017, where plans for a full revamp of the truck were executed. In addition to comprehensive suspension and drivetrain upgrades, a brand-new look came in the form of a 2017 Ram 2500 fiberglass body from Brothers Racing Bodies. All USHRA (Monster Jam) safety requirements were met, and a common-rail Cummins was bolted in place mid-chassis. Now, the truck is safer, makes considerably more usable power, burns cleaner—and looks good doing it.
D&J Enforcer
Using much of the same technology that put its drag truck in the 8s, XDP turned to common-rail injection for version 2.0 of the monster truck. After contacting D&J Precision Machine, Dave and team settled on an Enforcer series Cummins—the same engine that’s earned three UCC championships, won a Pro Street drag racing title and set multiple
E.T. and trap speed records.
The 6.7L-derived, cast-iron block is sleeved, fire-ringed and fitted with a deckplate. It incorporates 9/16-inch ARP main and head studs and uses a girdle to tie all the main caps together around a factory-based crank. One-inch-longer, tool-steel X-beam connecting rods utilize ½-inch ARP bolts on the big end and attach to valve-relieved, 15:1 compression FSR pistons up top.
Competition Cylinder Head
Filling the cylinders with air is a Stage 3 commonrail head that flows 80 percent more than stock. Like the block, D&J’S 24-valve head is fire-ringed and was originally intended for the 6.7L Cummins. Cutting-edge, five-axis CNC porting, a high-performance CNC valve job, larger, 1.500-inch intake and 1.450-inch exhaust valves, 115 ppi valve springs and D&J’S billet replacement intake manifold all contribute to this competition-ready hunk of iron flowing as much as 300 cfm per intake port. The freer airflow contributes to engine longevity. Compared to a restrictive stock head, lower boost pressure can be run to make the same horsepower.
High-speed Diesel
While the Auto Meter tachometer in the cab reads up to 10,000 rpm, at Dave’s request, engine speed is governed to 5,700 rpm. To be sure, the Cummins spends most of its time well below that engine speed, but in instances where the truck is purposely put on two wheels during the course of a performance, the extra 1,0000 rpm allows Dave to drive out of it longer. (Full disclosure: We’re told that engine builder Drew Pumphrey is fine with the Cummins revving out even higher than that.)
Two CP3S, Two Stages of Boost, Smooth Power
What are the keys to the Enforcer’s 1,800-plus horsepower figure? Big fuel, compound turbos and sound EFI Live tuning. Using D&J Precision Machine’s innovative billet front cover,
a Waterman fuel pump and two 13mm CP3S from Dynomite Diesel Products are gear-driven off the front of the engine. The stroker pump combination feeds diesel to a set of DDP custom-built injectors. Capitalizing on the exceptional head flow, XDP spec’d and built the compound turbo arrangement, which pits a Garrett GT55 atmosphere charger with a GT4202 high-pressure. Going over the 6.7L ECM calibration with a fine-toothed comb during a live tuning session, Done Right Diesel Performance’s Ben Shadday optimized the engine for ultimate longevity, power production and cleanliness.
Two-speed Lenco, Four-disc Centrifugal Clutch
Whereas most blown-alcohol monster trucks make use of Powerglide/converter setups, the XDP rig relies on a twospeed Lenco with a four-disc clutch from Valair.
Why? When different forms of competition are held at the same venue (i.e., racing and freestyle), a different stall speed is required in order to be competitive in both. And because diesels are known to melt torque converters, the only logical option was the Lenco with a weighted centrifugal clutch. So far, it’s worked flawlessly and has yet to be touched since being installed.
“Plus, if you get the weights on the clutch just right (as we have), I can stall it on the line, and it acts like a converter,” Dave explained.
Dropbox, Rockwells and Planetaries
On its way out of the Lenco, a drop box-style SCS gearbox transfer case diverts horsepower and torque to both axles. The axles, themselves, are made up of Rockwell F106 center sections, Patrick Enterprises Inc. sheet metal differential housings, SCS gearbox axle shafts, an Ouverson USA locker up front and an Ouverson USA spool in the rear. For further gear reduction, as well as taking considerable stress off of the Lenco, 4.5:1 reduction Pettibone planetaries are located at each end of the axles. As far as overall gearing is concerned, the diesel engine prefers load (and it certainly helps spool the chargers), so Dave runs taller gearing than the competition at all times.
“In a small arena, I’m running the same transfer case gear that an alcohol truck would run in a wide-open stadium.”
Memorable Moments
Even though Dave has been behind the wheel of various alcohol-powered monster trucks over the years—including “Bigfoot” 18, 19 and 20, “Iron Outlaw” and “Bounty Hunter”—his most memorable moments have taken place under the power of diesel. This includes lining up next to the truck he’d idolized in his youth.
Aboard the original truck at Utah’s Rocky Mountain Raceway back in 2008, Dave said, “I pulled up to the starting line, looked over and saw ‘Bigfoot.’ I had jackedup trucks even before I had my driver’s license, and ‘Big Foot’ was my idol.”
For the Fans
A pivotal moment in both Dave’s career and the course of things to come for the XDP monster truck program came in 2012, when, after the truck was freshly wrapped onsite at the venue at which it was set to compete, Dave put the truck on its roof as soon as the show began. And not only that: He’d landed on blacktop, meaning the truck had incurred considerable damage.
“I just threw my arms up on top of the cars that just wrecked me, and the fans of Springfield, Ohio, went wild!”
At that point, he stamped out his concerns for the truck’s
cosmetic damage and realized that fans pay good money to see the trucks perform—not for their looks.
“Now, it’s all about the fans and putting on a good show.”
Always Advancing
Things have definitely come a long way since debuting that first Hushpower-sponsored truck, and Dave is the first to admit it. Thanks to XDP’S unwavering support and extensive resources being poured into its monster truck program, Dave and team have been climbing the proverbial “ladder” for more than seven years now.
To confirm just how competitive the truck has become under the XDP nameplate, Dave explained, “Back in the day, the alcohol trucks I was racing against were idling on the starting line, but now, they’re up against the converter. What does that tell you?”
Bigger Things to Come
Things are far from over, though. With the release of XDP’S second-generation truck, expectations are high—and Dave is just the man to deliver.
A recent relocation to Citrus Springs, Florida, allows him to test the truck in fairer weather and on a year-round basis; and the clean-burning common-rail powerplant gives him and Team XDP the best chance of competing regularly along the indoor circuit.
We can only imagine the memories that are about to be created with this new, cutting-edge machine.