Click for Coverage
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler
X

Custom Rock Buggy - Bugg'n Out

Posted in Features on June 1, 2003
Share this

At the 2002 UROC Super Crawl in Farmington, New Mexico, the unmistakable whine of a semi-uncorked VW mill could be heard resonating through the midway. While attempting to distinguish it from the general cacophony, there emerged from the crowd of onlookers a pint-sized sandrail - of a sort. At the wheel was none other than Jon Bundrant, owner of All Pro Off-Road.

For decades, venerable air-cooled VW mills have been providing reliable, rock-solid, work-on-it-anywhere performance. Motivating everything from champion Baja 1000 rigs to lightning fast sandrails and 10-second dragsters, it was only a matter of time before one ended up in a competition rock buggy.

Affectionately named Tiny for its pint size and weight, Tiny is the creation of Jon Nelson, owner of Nelson & Nelson Engineering, which is well-known for building champion cars for the NASCAR and Spectra series, as well as Baja 1000 rigs for Larry Ragland and Walker Evans. "Nascar regulations have become too limiting," says Nelson, and "rock rigs are the last engineering challenge available. It lets us expand our creativity; start with a clean sheet of paper, and expand on it." The objective was to engineer a highly competent rock buggy with a delicate balance of horsepower and mass capable of exceptional four-wheeling finesse - and design it around an air-cooled VW powerplant.

Tiny's heart is an air-cooled, horizontally opposed 3.0L VW mill. The German powerplant reportedly puts out 170 hp and 240 lb-ft of torque. Aspiration is managed by a Motec Fuel Management system, while spent gases are expelled via an aluminum header and Flowmaster muffler. Purposely built for rockcrawling, the fuel cell is a custom unit containing a miserly 3.5 gallons.

Forward of the engine (remember, this is a rear-engine rig) is a GM Powerglide two-speed slush-box tranny (that's an automatic for you non-gearheads). Weighing in at a scant 80 pounds, the Powerglide provides smooth, reliable output throughout the powerband. Managing power distribution duties through a set of Inland drivelines is an Atlas II 4.3:1 transfer case. Mating this team together is a pair of custom fabricated adapters.

Tiny's engine is transversely mounted at a slight angle to the vehicle's centerline, and out back, as a VW mill should be. When mated to a conventional tranny/T-case setup, the drivelines rotate opposite that of a forward engine design. Romp on the pedal with conventional axles under this rig and you'll get a close up look at the steering wheel (you'd be going backward).

The solution came from Currie Enterprises in the form of a pair of Detroit-locked, extreme offset 9-inch axles. The aluminum center sections were inverted to provide proper rotation and loads of driveline clearance. The configuration also allows the rear pinion gear, which shoulders the majority of abuse, to contact the appropriate side of the ring gear. The extreme offset was accomplished with a pair of 35-spline Currie axleshafts. Wilwood 11.75-inch disc brakes cap the ends. Up front is a similar setup with the addition of Dana 60 knuckles and 1350 U-joints.

Three-links and a Panhard rod manage axle placement and articulation, while Sway-A-Way coilovers mated with Eibach springs handle damping duties. Directional control is maintained via a custom Howe hydraulic steering setup.

To maintain the featherweight concept, the entire frame and suspension was fabricated out of 4130 chromoly tubing. Additionally, the forward-mounted 2500 Warn winch is wrapped with lightweight Master Pull winch line. Other trick items tucked safely inboard the front frame hoop include an aluminum trans cooler and an Optima battery.

Now, we're guessing that right about now you're probably saying, "A VW? Give me a break." But don't laugh. Put this little rig on a set of 37-inch BFG Krawlers wrapped around MT 17-inch beadlocks, and you've got a serious contender. With the paint barely dry, Bundrant finessed up Tiny's featherweight tailpipe with some of the most insane obstacles we've seen. And he managed to keep the rubber side down throughout the entire weekend. We'll probably be seeing more of Tiny in the upcoming season. And who knows? Maybe one day some of this technology will trickle down to your trail rig.

SPECIFICATIONS
Owner: Jon Bundrant
Year/make/model: Custom Rock Buggy
Engine: 3.0L VW
Transmission: GM Powerglide
Transfer case: Atlas 4.3:1
Frontend: Currie 9-inch w/ Detroit
Rearend: Currie 9-inch w/ Detroit
Ring-and-pinion: 4.88
Suspension: Custom three-links front and rear with Sway-A-Way coilovers andEibach springs
Wheels/tires: 37-inch BFGoodrich Krawlers / Mickey Thompson 17-inch with beadlocks

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results