RJ Anderson’s Walker Evans Polaris RZR Race Build
At only 16 years old, RJ Anderson was already establishing himself as one of the most promising young drivers in UTV short-course racing. His purpose-built #637 Walker Evans Racing Polaris RZR backed up that reputation by winning in its first appearance.
Anderson entered UTV competition after racing go-karts and competing in the Junior Sportsman/HPV 2 ranks. He went on to race in the TORC and M4SX series, quickly producing an impressive record. Across his first 15 UTV races, Anderson earned six victories, six second-place finishes and two third-place finishes.
His new Walker Evans Racing RZR debuted during Round 7 of the M4SX Series, where Anderson immediately drove it to first place.
RJ Anderson’s Walker Evans Racing RZR became the principal Polaris challenger to three leading Kawasaki programs. Explore the complete Kawasaki Teryx and Polaris RZR short-course racing rivalry, from the original RZR 800 through Anderson’s RZR XP 900 championship.
Purpose-Built Holz Racing Chassis
Although it retained the identity of a Polaris RZR, the #637 was far removed from a stock production machine. Holz Racing Products constructed the race chassis from the ground up and equipped it with a +8-inch long-travel suspension system.
Walker Evans Racing supplied the 2.5-by-10-inch shocks, dual-rate springs and beadlock wheels. Holz race spindles, Summers Brothers axles, ORW billet hubs and a Team Industries clutch helped prepare the drivetrain and suspension for the demands of short-course racing.
Kroyer Racing Engine Producing More Than 90 Horsepower
Kroyer Racing Engines built the RZR’s high-output engine with a new cylinder, pistons, cylinder head, valves, camshaft and throttle body. The combination reportedly produced more than 90 horsepower—a substantial figure for a Polaris RZR race engine in 2009.
The custom race engine was based on the Kroyer/Holz Stage III package, which was available to customers with a claimed output of approximately 70 horsepower. Anderson’s engine took the concept considerably further with additional race-specific development.
A MoTeC EFI system managed fuel delivery, while a Holz Racing Products billet intake manifold and K&N air filter handled the intake side. The cockpit also featured a MoTeC dash, CNC pedals and a Momo steering wheel.
Kroyer Stage III Polaris RZR engine kit and dyno comparison.
RJ Anderson Polaris RZR Specifications
- Holz Racing Products purpose-built race chassis
- Holz Racing Products +8-inch long-travel suspension
- Walker Evans Racing 2.5-by-10-inch shocks
- Dual-rate shock springs
- Walker Evans Racing beadlock wheels
- Holz Racing Products race spindles
- Kroyer Racing CNC-ported cylinder head
- Kroyer Racing camshaft, pistons and valvetrain
- MoTeC electronic fuel injection
- Holz Racing Products billet intake manifold
- K&N air filter
- Goodyear MTR tires
- ORW billet hubs
- Holz Racing Products billet engine mounts
- Holz Racing Products front bumper
- Mastercraft seats and safety harnesses
- MoTeC digital dash
- CNC pedals
- Momo steering wheel
- Team Industries clutch
- Summers Brothers axles
Build Photo Gallery
Build Sponsors
- Walker Evans Racing
- Holz Racing Products
- Kroyer Racing Engines
- South Point Hotel & Casino
- Goodyear Tires
- Mastercraft
- HJC Helmets
- Polaris Racing
- Team Industries
- ORW
A Winning Debut for the #637 RZR
The #637 showcased just how quickly Polaris RZR racing had evolved by 2009. Its custom Holz chassis, long-travel Walker Evans suspension and 90-plus-horsepower Kroyer engine made it a serious short-course race machine rather than a lightly modified production UTV.
More importantly, RJ Anderson proved the new build’s potential by winning its first race. The result added another victory to the young driver’s rapidly growing record and offered an early look at a racer who would become one of the most recognizable names in the UTV industry.
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