An Inside Look at the Miller Brother’s Purpose-Built KOH 4400 Class Can-Am X3s
Words: Angela McCorison
Photos: Brandon Bunch, HighRev Photography, Justin W. Coffey
A few short years ago, if someone told you a UTV was going to compete in the Race of Kings, 4400 Unlimited class at KOH, you would probably laugh at what you thought was a joke. Well, us too actually, but by now, we all know that not only can a UTV race with the big boys on the harder/longer course, but it can also finish in the Top Ten! With 1/4 the horsepower at roughly half the size of a typical 4400 race car (not to mention one-fourth the cost), you may ask yourself what kind of modifications gave these Can-Am X3s such a high level of capability. Likewise (very) curious, we cornered Hunter Miller at this year’s KOH to ask him if he’d reveal the Miller Brothers Can-Am team secrets. To which he obliged… a bit.
Because, like us, you might be wondering how the idea of racing a Can-Am X3 in the 4400 class even came to fruition, Hunter explained their motivation:
“At KOH in 2020, Cody and I competed in the UTV race, and Cody, unfortunately, had a bolt break about five minutes into the race. It took about 20 minutes to fix it, and he was able to come back up to 9th place thereafter. I won the UTV race, and because Cody and I are very competitive with each other, Cody was obviously perturbed. I flew home later that night, but Cody stuck around. The next morning at breakfast, the Can-Am guys joked that he should just stay and race 4400. And this lit something in Cody who immediately thought, ‘wait, can I race 4400?’ So, he talked to Dave Cole and the Ultra4 guys who were quite stoked on the idea. Chad (Hughes) rode with Cody. They blew a front diff on Lap One and were down for an hour – ultimately finishing 23rd.”
That event is what started Hunter and Kyle’s (Chaney) wheels turning. Knowing Cody finished the 4400 race was the real inspiration. It was possible! So, they were determined to do it again, but better. The very next year at KOH, they all three raced the 4400 Unlimited event. Unfortunately, Cody had a tough time, breaking all four axles at once on Sledgehammer. Hunter ended up helping Kyle with an issue on Outer Limits which led to them both finishing 10th and 11th. Then, last year at KOH in the 4400 Unlimited race, Cody managed to take 8th, while Kyle and Hunter both broke down. It’s progress, but the boys aren’t worried about results, nonetheless. “We have everything to gain and nothing to lose – no one expects us to win,” said Cody.
But 2023 KOH was a whole different story for Hunter, Cody and Kyle as this was the first year they brought separate purpose-built Can-Am X3s for the 4400. It would make sense to think they had different machines to run the UTV event and the 4400 in previous years, but you would stand corrected. They would literally burn the midnight oil to prep their UTV Race Can-Ams (on Thursday) to be ready for the 4400 Race (on Saturday). “In prior years, we would spend all day and all night refreshing the car before the 4400 Unlimited race. Basically 24 hours of prep work to try and ready the car for the next race,” recalled Hunter.
For the most part, the Millers share everything with Kyle and his crew since they are all Can-Am teammates. But the actual setups and designs are different. Kyle’s ideas on how a car should look and work are a far cry from how Cody and Hunter envision theirs. Nearly identical, their UTVs possess only slight changes due to driving styles and personal preferences. This year’s Race of Kings was as brutal and merciless as ever – only 30 racers out of 107 entries actually finished the race in the allotted time. And despite the chaos and havoc the boulder-filled course caused, Hunter did exactly what he set out to do: beat Cody’s best-yet finish of 8th place.
Hunter took 7th place with Cody coming in right after him in 8th again. However, Kyle ultimately DNF’d on Lap Two. Cody thought back: “Ya know, my brother and I race the same class in everything. We’re always finishing basically within one spot of each other. We’re very equal competitors, and we have kind of an advantage on the field because of this. [Hunter] is definitely a little bit more conservative than I am. He’s a more methodical, smooth driver. I’m kind of reckless and wild.”
Whether they were out there to clear the field or just to outdo each other, it took some serious work to build their X3s into true “kings” of the desert. They were kind enough to offer a hot-list of upgrades, which we of course dutifully noted. We were eager to know whether they run portal axles, 37” tires or anything way out of the norm for a UTV race build. Hunter was kind enough to let us put his (#190) 4400 Can-Am X3 build under scrutiny, noting the main differences between it and his UTV race Can-Am. Here are the main mods, with details to follow:
- Boat sides
- Fuel cell (bigger and relocated)
- Stronger/reinforcing added
- Bump stop setup
- 35” Tires (next year likely 37”)
- High clearance trailing arms
- A-arms (slightly different)
- Relocated sway bar
- Stock interior, dash and plastic panels removed
- Winch knob added to dashboard
- Lighting for night driving (since it’s a longer race)
- Widened rear for spare tire
- Custom exhaust
- Bigger J.Juan brakes
The boat-sided chassis helps with navigating through technical rock sections. “The belly of an X3 is pretty wide so boat-siding it helps to slip through the rocks, but, honestly, it didn’t make a ton of difference. The pre-runner made it through it as good,” said Hunter.
The fuel cell was relocated behind the seats and custom made to hold more gas. The relocation also helps shift more weight back. (The fuel cell holds 20 gallons and can take 10 gallons in 2 1/2 seconds at a pit stop.) They added tubing and gusseting to the car mainly in the rear. This is partly due to adding a bump stop setup (bump stop hitting over and over) and mainly for safety in case they are hit from behind. “There is a definite possibility we could be hit in the rear by a Trophy Truck flying through the desert at 120mph with dusty conditions.” – says Hunter.
The bump stop setup was added to the front and rear of the purpose-built 4400 Can-Am to help the car handle huge G-out dips at full speed without slamming the frame to the ground. With the shock now bolting on the lower arm and added bump stops, the A-arms are slightly different. They can still run their suspension soft and compliant so when the shock reaches the bottom of the stroke, the bump stops step in, preventing the frame from contacting the earth.
Several small tweaks add together to create the bigger, heartier picture. Their shocks have the same valving but were tuned differently. The trailing arms are the same length but are a higher clearance with the addition of a jack mount on either side. Primarily due to new packaging, the sway bar was relocated because the repositioned fuel cell was then in its way. The stock dash and plastic panels were removed mainly for weight savings. They then added simplistic sheet metal doors with a reinforcement tube built inside for safety, again mainly in case they are hit by a big car or trophy truck.
Due to the higher likelihood of using the winch in the 4400 race, a winch knob was added to the interior. With the knob the driver can unlock the winch while the co-driver jumps out, grabs the hook and runs it up to a hook point. The driver locks it while winching them up and spools the cable back in. In Hunter’s other X3, the co-driver has to unlock the winch outside of the car after jumping out, then pull the line and hook it up and then run back to the car to lock it before they can winch. This is truly a time-saving device.
On top of that, lighting was added since the King’s race is one lap longer than the UTV iteration, making driving at night a more likely possibility. Hunter and team intended to run a 37” tire this year, so they widened the rear end of the Can-Am to fit a 37” spare tire (horizontally). They ended up sticking with 35” tires and instead designing a custom exhaust to fit the new package. And to accommodate the heavier weight and larger wheels, J.Juan brakes were added to the package.
Hunter puts it this way: “Even though it looks kind of wild, it’s still very much a stock X3; the heart of it is all the same as stock…” He continues, “stock diff, drivetrain, axles, power plant, trans, clutching, hubs, steering rack, power steering, and electrical system are all Can-Am original. Most of the chassis parts are stock, and we didn’t cut a single tube out of the car.”
Although not mods so-to-speak, tools are very important to pack with you in various places. The Millers carry their tools in door bags, a spare tire bag, and a tool-roll carrier underneath. Things you find in Hunter’s X3 include an impact gun (sometimes two), a full set of wrenches and sockets, basic hand tools, specialty tools for changing belts, AGM jack, tools to change spare parts like axles, driveshaft, and tires. Parts like nuts, fasteners, hose clamps, spline lug nuts, one belt, one axle, one driveshaft, one tire which are promptly replaced or replenished at a pit stop if the items are used for a repair on course. Smaller parts (the nuts and hose clamps for instance) are also carried in the spare tire bag. Large parts are carried throughout the car, mostly mounted on the cage. Plus, axle pins, electrical items, zip-ties, miscellaneous fasteners, a rope for wrapping around rocks, and spare winchline.
Hunter’s favorite and arguably most important mod is a Hess steering quickener. “One and a half turns for stock, just half a turn for Hess,” he said. “It helps avoid surprises and move faster in switchback turns. After you get used to it, you feel a lot more connected to the car, a lot more a part of it. And it’s a bolt-on, non-expensive mod! I don’t even like to drive without it anymore. It is not for beginner level drivers though, it’s really easy to cut the wheel too fast and roll it.”
As far as overall mods to their X3 builds, the Millers have a lot of upgrades which are common to many builds. At the front of the X3, you’ll find a Warn 5500 lb. winch, gusseting for strength, radiator relocation (to the back), suspension arms with 100% stock geometry but aftermarket for added strength, billet dual-shear knuckles, shocks custom tuned by Double E Racing, an aftermarket bumper, and a custom fabricated roll cage for strength (120 wall – 1.5”). Progressing to the middle of the X3, you’ll see a communications system, GPS, AIM Sports unit (data acquisition/recorder), window nets, Recaro seats and mounts, Sparco harnesses, UHMW 1/2” full under belly skid plates plus rocker skids, that aforementioned radiator, intercooler and CVT ducting.
In the rear of the X3 is a new roll cage design for the spare tire. The wheel sits lower and rests on the cage relying on the Speed Strap tire Y-ratchet strap to hold it in place. And then there are the trailing arms with added gussets, high-clearance radius rods, adjustable sway bar, and electric fans (for custom the CBR radiator). We couldn’t help but ask Hunter what his thoughts are on portal axles. He said he has considered it for the 4400 class, but it does add a lot of weight and would need more R&D before he would use them in a serious competition. So, it’s still a possibility that we may see portals on a future 4400 class Can-Am X3 build. And who knows what else is to come with these elite drivers. Considering their finishing averages over the last few years, one of them is bound to shame some of their beefier adversaries in the Race of Kings. (One can only hope.)
The Miller brothers clearly have a formula for success, so keep an eye on them via their social channels: @MillerBrothersRacing, @huntermiller90, @cody_miller_22. A huge thanks to Hunter for taking the time out of his super busy KOH schedule to patiently talk over the Can-Am X3 build details with us!
Hunter adamantly stated that they couldn’t be successful without their co-drivers Chad Hughes and Cody Taylor and all of their sponsors: @hughesoffroad @canamoffroad @texplexpark @texplex_racing @maxxistires @racelinewheels @elkasuspension @double_e_racing @s3powersports @teixeiratech @ssidecals @factory_utv @sparcousa @hessmotorsports @tireballs @tireballseast @louispowersports @kellerperformanceproducts @aimsportsdata @antigravitybatteries @dpbrakes @hmf.engineering @gatesgforce @warrantykillerperformance @warnindustries @renegadefuel @ppei_tuning @pit_viper @buttersupplyco @dixxonflanelflannelco @monster_seal @bajadesignsofficial @runbc
