|Holz Racing Products 1964 RZR XP 1000
By Cody Hooper, Photos by Robert Utendorfer
A look inside building a Best in the Desert Pro UTV Race Car
It seems apparent to us that everyone who slides behind the wheel of a sport UTV these days thinks they could podium a desert race. Some of the comments we hear from novice drivers make us cringe- not because we think we could win the races ourselves, but out of respect for the wide open Southwestern deserts. If there was ever a place that could turn a brand new UTV into a wadded up pile of steel and tires, its the dez.
Knowing how hard it is to keep a near-stock unit together in the brutal Best in the Desert series, teams like Holz Racing pour countless hours of development and testing time into their race cars. What may look overbuilt to the untrained eye can still succumb to fatigue in the great Southwest, and well-built cars win races, not fast drivers.
Meet Holzs newest race car, 1964. The number designates the class first- 1900 series vehicles are defined as a UTV with a stock bottom end and cylinder head, no more than 70 wide, using stock chassis dimensions and suspension mounting points, with no more than one shock per corner and no larger than 30 tires. The class rules are quite strict, and the BITD tech inspection is meticulous, so as to keep the competition fair.
Holz starts with brand new cars for their builds, tearing them all the way down to the frame and stripping the paint. Reinforcing bracketry is added to all stressed points on the chassis, including upper A-arm tower braces, a full welded 4130 chromoly cage, new steering linkage, and a host of sheetmetal covers and firewalls to protect both vehicle vital parts and passengers. While this may look like an XP1000 from the outside, the car is completely overhauled from the ground-up to ensure it can withstand the constant torture of desert racing.
Holz manufactures a custom +2 suspension kit that also increases the wheelbase by 3 inches. Rather than chase huge travel numbers, Holz keeps the wheel travel conservative enough to save the shocks and CVs from overexertion. They use a very specific Walker Evans 2.5 shock setup with huge reservoirs and nearly unlimited adjustability. The VS2 shocks feature a strange-looking piggyback setup that is positioned mid-way down the shock body, giving Walker the ability to lessen the reaction time for the rebound and compression adjustment circuits.
Holz modifies many of the OE Polaris components for racing use, including the CV joints, transmission, and clutches. Since the rules state that OEM clutches must be used, Holz is only allowed to tune and modify the OE pieces for increased durability. Summers Brothers 300M axles replace the OE units, and a Howe steering rack is swapped in for parts longevity.
Wheels and tires come courtesy of Walker Evans and BFGoodrich. The 15 beadlock Walker wheels have that classic racing look, while the brand new 30x10R15 BFG KR2 race tires provide ample grip and extreme puncture resistance.
Inside, a host of switches graces the sheetmetal dash. A Lowrance GPS unit sits ahead of the passenger for navigation and course mapping on the long desert runs. Sparco carbon fiber seats offer incredible body control and are much lighter than the stock units, and a Sparco steering wheel with Holz quick release hub sits atop a steering stem that is welded in place for durability.
Lighting is provided by Vision X, and there arent a host of LED lights on the car. With a minimalistic approach, Holz was able to keep the weight of the car reasonable, which leads to higher speeds and less parts fatigue. The stock XP 1000 engine has been modified with a dry sump oil system by Holz with increased oil and cooling capacity, using an auxiliary Setrab oil cooler mounted above the rear bedside to help the engine maintain its composure. A massive Ron Davis radiator and fan are positioned just behind the center line of the vehicle, taking in all the cool air that flows through the windshield opening.
With years of racing experience, Holz has figured out what needs to be beefed up on these cars, and what can remain stock. Their focus on chassis and driveline strength over sheer power and horsepower means the cars hold up very well in the desert, which is often the key to winning a race. It doesnt matter how fast you can drive if you cant cross the finish line.
This car made its debut at the Silver State 300 race in Nevada this year with only a single day of testing under its belt. Mark Holz and his son Ryan led the race with a comfortable 6 minute lead on second place when a cam chain tensioner let go at race mile 206. Unfortunate, yes, but the car proved that it could hold its own, even with limited testing time.
Holz Racing Products sells many of the components they use on their race cars for personal use- in fact, they sell suspension kits, shocks, wheels, tires, bumpers, race components, and even chassis builds. If youre looking to get into racing, do yourself a favor and call (360) 398-7006, and tell them UTVGuide.net sent you!
Holz Racing Products // 6226 Chasteen Road // Lynden, WA 98264 Phone: 360.398.7006 // Fax: 360.398.0267 // firstname.lastname@example.org // www.holzracingproducts.com