How Holley Got This Ultra 4 Racer Back On Track In The Nick Of Time

10 min read

How Holley Got This Ultra 4 Racer Back On Track In The Nick Of Time

10 min read

“I’ve always been bit of a speed demon,” says entrepreneur and off-road racer Tommy Dykstra. “I started racing doing hare scrambles on four wheelers, and from there I went to shifter karts. I’ve always enjoyed the endurance formats, where you get to spend hours on track.”

Following a stint in diesel truck drag racing, Dykstra turned his attention back to off-roading when he acquired a lightly modified Jeep Wrangler and set to work getting it ready for some serious abuse. But after going through a few progressively more-potent iterations of the JK, he considered pivoting to another platform. “I put about a thousand miles on the second version of the build and I realized it still just wasn’t enough,” he says. “So at that point, I thought about putting together a side-by-side to go race at King of the Hammers instead.”

But after watching GenRight Off Road president Tony Pellegrino compete at the 2020 King of the Hammers event in a JK Wrangler of his own, Dykstra had a change of heart. “It just looked like a lot more fun than the RZR would be,” he says. “So I immediately got on the phone with them.”

Dykstra Ultra 4 side profile

Since 4400 is Ultra 4’s anything-goes unlimited class, most racers compete in purpose-built race buggies. But despite the inherent disadvantage of building a 4400 racer on a production chassis, Dykstra is now running competitively with pro drivers. His JK Wrangler rolls on 40-inch Mickey Thompson off-road racing radials.

Dykstra and the team at GenRight soon reinvented the Jeep as a race-ready machine, installing the company’s three-link front suspension and a four-link out back, along with Currie axles, Branik Motorsports 300M axle shafts, and Auburn Lockers. They also ditched the boosted V6 powerplant in favor of a naturally aspirated 700hp 7.4-liter all-aluminum LSX mill from Denton Racing, and backed it up with a 4L80 transmission with a reverse manual valve body. “When you’re climbing big, steep stuff, being able to just shove the shifter forward to go into reverse is really helpful,” he points out. “Normally you’d have to shift through all the gears to get back to reverse, and a second can make a big difference when the truck is about to tip.”

Dykstra set his sights high and built the Jeep to be eligible for Ultra 4 4400, an unlimited class where purpose-built, tube chassis race vehicles normally compete. “I knew it would be tough to get podiums in this class, but I wanted to run 40-inch tires and this is the only class that allows it,” he says. “Ultimately the goal was to build something that could be reliable when driven this hard and wouldn’t need a ton of work after every race. It still has back seats – I drive it around on trails with my family all the time.”

He started out with a GM engine management system, but quickly discovered its limitations. “I had a ton of problems with it. It just wasn’t very racer-friendly. That computer took me out of the race at King of the Hammers earlier this year – the throttle pedal would just disappear without warning when I would hit something hard. It actually caused me to roll over. So that’s when I started looking into alternatives.”

Dykstra Ultra 4 engine bay

The Jeep’s current powerplant is a 7.4-liter all-aluminum LSX engine from Denton Racing that dishes out 700 horsepower and 660 pound-feet of torque. It’s a pretty big upgrade from the 202hp 3.8-liter V6 that the Wrangler started out with. Dykstra tells us that he opted for Holley's tapered LS throttle body because it allows for finer throttle control at low speeds – a feature that’s particularly helpful when you’re crawling over a four-mile rock trail.

After getting several recommendations, he switched over to a Holley Dominator EFI system, along with a tapered Holley throttle body for more nuanced throttle control at low RPMs. Once the system was installed, Dykstra headed down to San Felipe, Mexico for its inaugural Ultra 4 race – a five-lap race on a 22-mile course that included four miles of rock crawling along the way. “It was the first race that I’ve run the race without one single problem with the engine management system,” he notes.

Running the practice sessions that led up to qualifying was a different story, though. “I had put a few hundred miles on the Holley system beforehand, but this was the first race it had seen. During the pre-running sessions, I found that I’d get a few miles into the course and then the system would give me crazy readings and shut down.”

Dykstra started troubleshooting, replacing the harness and sensors to try to remedy the issue to no avail. Frustrated, he reached out to Ultra 4 race director JT Taylor, who in turn put him in touch with Holley EFI Motorsports team members Andrew Starr and Bryan Grigsby. “Typically the installs we help out with are at engine shops, race shops, and that kind of thing,” Starr explains. “In these situations the troubleshooting is often more advanced because they’re generally custom installs, and that means there’s a lot of nuances involved that you don’t come across in more common applications.”

Dykstra Ultra 4 cockpit

The cockpit is outfitted with two Holley EFI Pro digital dashes – a 12.3-inch unit for the driver and a 6.86-inch display for the co-driver. “I have the co-driver limited to a few vitals – he’s also got to look at the map and keep us on course, so it’s sort of a backup system in case I don’t notice something is up.”

With the race event soon approaching, Dykstra and Starr worked through the problem over the phone. “Usually the data logs will give you some insight into what’s going on with the product and a potential remedy,” Starr says. “But in some cases that information either isn’t available, or it wouldn’t help solve the problem. In this particular case we couldn’t capture that information because the vehicle was just shutting off. But the big clue was that the data was also being corrupted – the numbers weren’t making any sense. That indicated to me that this was an interference issue.”

Starr adds that when data is corrupted while the system is running, there’s typically a common culprit. “It’s because of interference caused by a USB cable. USB cables are usually considered pretty innocuous, but they’re highly sensitive cables, and it can actually feedback into the ECU. And in this case, we discovered that this communications cable was in a very precarious position.”

Dykstra Ultra 4 suspension

GenRight’s three-link front suspension provides articulation up front, while their four-link system keeps things in check at the rear.

With less than an hour before qualifying, Tommy disconnected the USB cable and went out for a lap to test the Jeep. “We ran the whole lap without any issues at all, so we knew that we had found the problem,” he says. “If it wasn’t for Holley’s support, I don’t think we would have been able to resolve it. If we had been running the GM system, who would we have called?”

Dykstra went on to finish mid-field in the 4400 race – not bad considering he was the only racer in field competing in a production Jeep chassis. “We beat sixteen purpose-built race cars out there,” he says. “And being able to finish that race secured us a spot for the 2022 King of the Hammers.”

In the meantime he’s got five more Ultra 4 races on this season’s calendar, after which the plan is to build a tube chassis monster for 4400 and switch the Jeep over to 37-inch tires for the 4800 class. “The goal right now is just to show that somebody that hasn’t been a fabricator for their whole life can build something and run competitively against professionals,” he adds. “I want to prove that if you’ve got the drive, you can make it happen.”

Dykstra JK Ultra 4


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