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Anatomy Of An Ultra4/KOH Buggy

Posted in Features on December 11, 2013
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If you’re into off-road racing then you probably know the name Shannon Campbell. Even if you’re not into off-road racing, you may still know the name Shannon Campbell. Forty three-year-old Campbell started wheeling in 1992. His first-ever off-road competition was at Top Truck Challenge 1996 where he took First Place. In 1997 he was desert racing in the same Jeep that he drove to win TTC the previous year. From there, his racing career took off and has included winning the incredible King of the Hammers (KOH) twice. Back in 2001 he opened Campbell Enterprises, which continues to this day. His company specializes in everything off-road, including Trophy Trucks, rockcrawlers, trail rigs, short course, Ultra4, and KOH machines.

A few years ago, Campbell rocked the off-road racing world when he built and raced an independent front suspension (IFS) rig at a time when there were no other IFS rigs racing in the Ultra4/KOH series. His follow-up to that rig is the buggy you see here, which is his newest machine. Campbell built the rig over the course of two months and its first race was in the fall of 2012. Like its predecessor, it is equipped with IFS. Campbell says he likes IFS because it offers him the ability to hold high speed and retain drivability. He notes that race buggies with a solid front axle can be “squirrely” in the same situation. Among other things, Campbell’s design goals for this rig included simplicity (package components so they could be easily replaced) and a 50/50 weight balance front to rear. Ultra4/KOH vehicles are unique in that they have to be part rockcrawler and part high-speed desert racer due to the vast array of obstacles and terrain they encounter in the course of an average race.

Campbell estimates that only about 10 percent of the buggies that currently race Ultra4/KOH are IFS-equipped. We think that makes his buggy unique and worth a closer look.


  • Custom Currie Enterprises chromoly differential housing, Currie third member with 9.5-inch ring gear, Motive Gear 4.29 gears, ARB Air Locker, Currie 300M inner stub shafts, ProAm Racing Products axleshafts, stub shafts, bearings, knuckles, and hubs, Arizona Driveshafts-built driveshaft using 1480 U-joints
  • Custom ProAm upper control arms made from 1.750-inch-diameter, 0.125-inch-wall 4130 chromoly tubing fitted with FK spherical rod ends at the chassis and a spherical bushing at each knuckle, custom ProAm lower control arms made from 3⁄16- and 1⁄8-inch 4130 chromoly plate fitted with ProAm bushings at the chassis and a FK spherical bushing at each knuckle, Fox 2.0 coilover shocks, Fox 3.0 piggyback bypass shocks, MasterCraft Safety limiting straps, 18 inches of suspension travel
  • Howe Performance Trophy Truck steering system with Howe rack, pump, reservoir, and pulley, Campbell Enterprises steering links made from 2-inch-diameter 7075 aluminum with FK spherical rod ends

Rear axle/Suspension

  • Custom Currie Enterprises housing with 9.5-inch ring gear, ARB Air Locker, Motive Gear 4.29 gears, Currie 35-spline 300M chromoly axleshafts, Arizona Driveshafts-built driveshaft with Campbell Enterprises carrier bearing and 1480 U-joints
  • Four-link suspension, ProAm 1.750-inch-diameter, 0.120-inch-wall lower links with 1⁄8-inch chromoly plate and FK spherical rod ends at the chassis and FK Uniballs at the axle, Campbell Enterprises 2-inch-diameter 7075 aluminum upper links fitted with FK spherical rod ends, Fox 2.0 remote-reservoir coilover shocks, Fox 3.0 piggyback bypass shocks, MasterCraft Safety limiting straps, Currie Antirock sway bar (with 22-inch arms), 26 inches of suspension travel


  • Turn Key Powertrain-built reverse-mounted GM LS7 V-8, bored and stroked to 440ci
  • Callies connecting rods and crankshaft
  • RaceTech forged pistons
  • Custom grind Comp Cams camshaft
  • GM Stage 3 heads with GM titanium valves and Comp Cams heavy-duty valvesprings
  • Turn Key Powertrain fuel injection with billet fuel rails
  • ArrowLane headers and exhaust tubing
  • Turn Key Powertrain engine wiring harness
  • Total Power TP-1500 battery
  • Dyno-measured 690hp and 650 lb-ft of torque at the crank

Transmission/Transfer case

  • Hughes Performance-built TH400 transmission with 3,000 rpm-stall Hughes torque converter, Hughes pan
  • Advance Adapters Atlas 3.0:1 transfer case


  • Custom aluminum dash panel with 12 toggle switches, 18 circuit breakers, Racepak digital dash, Lowrance Elite 5m GPS
  • Momo steering wheel
  • Center console with carbon fiber panel, Art Carr transmission shifter, levers for the cutting brakes, levers for the ARB Air Lockers, battery-disconnect switch
  • Lower center console holds two custom aluminum T-case levers and the fuel vent shutoff
  • MasterCraft Safety 3G seat with MasterCraft restraints


  • Forward-facing KC HiLites HID lights
  • ProAm four-wheel disc brakes with 13-inch-diameter rotors, six-piston calipers, Wilwood pedal assembly and reservoirs, CNC cutting brakes
  • Warn 9.0 winch with Warn synthetic rope


  • 40x13.50/17 Maxxis Trepador tires (typically aired at 20 psi)
  • 17x8.5 Walker Evans beadlock wheels


  • Campbell Enterprises custom chassis made mostly from 1.750-inch-diameter, 0.120-inch-wall tubing
  • Mid-mounted Ron Davis aluminum engine radiator with dual 16-inch electric fans, mid-mounted Ron Davis aluminum transmission cooler with fan
  • Campbell Enterprises-built 42-gallon fuel tank with Fuel Safe Racing Cells bladder, Walbro electric fuel pump

Exterior/Skidplating/Ground clearance/Weight

  • A combination of aluminum and carbon fiber body panels including a custom carbon-fiber roof panel with air intake for the cooling system, graphics by Banners Plus
  • Aluminum underbody skidplating is 3⁄8-inch thick
  • Rear axle centersection to ground: 14 inches, front skidplate to ground: 16.5 inches, bellypan clearance: 24 inches
  • Weight: 4,200 pounds, including driver

About This Series
This is the third installment of the “Anatomy of a…” series. In this occasional series we’ll take a look at the tech (or lack thereof in some cases) that’s integrated into four-wheel-drive vehicles that we may not normally feature. Some of these vehicles are packed with tech, others may be surprisingly simple, and some may have unique features that are specific to their type of wheeling.

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