Double the power, double the fun. And cue an extra dose of blood, sweat, and tears.
The "RR7" scrawled in permanent marker across the rear metal paneling was the first sign of a new Rebel Racing creation: An off-road vehicle designed and built to compete in Baja SAE, an international, collegiate vehicle racing series.
The UNLV Society of Automotive Engineers has been here many times before in preparation for their annual competition season. But this year they face a fresh challenge: a new rule that could throw a wrench into their best-ever finish last year. This year the team team has to find a way to send power to four wheels instead of two.
“All of our vehicles in the past have been two-wheel drive, and this year, they gave us a new set of rules, which required a 4WD design, and also, a brand new engine from a new event sponsor,” said Ashton Pearson, UNLV Rebel Racing project manager. “Their advice? ‘Make it work.’”
And that’s what they’ve set out to do, even as the starting line of the May 31 competition inches closer and closer.
A Winning Formula
Pearson believes the team has perfected a winning formula over the 15 years the student organization — one of the most active in the Howard R. Hughes College of Engineering and on campus — has existed.
“We never truly start from scratch because we try to recycle things that work,” said Pearson. “That’s how we started out this year. We took the RR6 chassis and said, 'What can we keep, what can we get rid of? How do we adapt this to make it work?'”
This wasn't always their approach. The first few cars the Rebel Racing group built after its inception in 2007 came from white papers. “You had nothing, and you had to figure out how to make it something from scratch,” Pearson said.
The team changed tack in 2015 — deciding to build off successes from previous cars — and finished the competition series about mid-pack.
Over the past few years, the team has earned better and better placements, with last year’s RR6 car earning top prizes across several categories, including third place at a competition in Arizona for endurance — Rebel Racing’s best-ever placement. They also earned a first place award in sales and first place in cost at every competition during the 2022 season.
“It’s not just about having a good car out on the track,” said Pearson. “It’s also got to be cheap, it’s got to be reliable, it’s got to be fast — it’s got to be everything, so that’s really the challenge.”
The team’s scrappy spirit is best encapsulated in the kudos they receive for cost at nearly every competition.
“We’ve gotten pretty good at building the cheapest car,” he said, adding that it’s also an important factor when considering the real-world implications of the design and build process.
“We have to try to sell this car, theoretically, and part of that is trying to get the costing down. SAE is trying to prepare us for the real-world in automotive engineering.”
Enter this year’s new rule: Teams are required to build a car powered by a 4WD system for the first time ever.
“More and more [utility terrain vehicles] are going 4WD, so we need to reflect that, too,” said Pearson. “We’re a prototype bed for the UTV market.”
And while Pearson champions SAE, and in particular, UNLV’s Rebel Racing organization for the real-world, hands-on experience that students receive by being active in the group, this year’s new rule is testing the team’s carefully crafted strategy.
RR7: Proving Its Mettle
As this season revved up, the team discovered pretty quickly that much of the winning design for the RR6 car wouldn’t work for RR7. In addition to the 4WD requirement, they also have to incorporate a new engine from a new event sponsor.
“The new engine I tried to shove in there wasn't going to fit, so the whole rear end structure had to change to fit that,” Pearson said. “And on top of that, we were given the 4WD requirement as well, so that rear end change had to go even further.”
The team had to raise the seat off the floor by four inches in order to fit the mechanical drive shaft, and had to figure out a way to fit a front differential into this year’s off-road vehicle.
“We have to put a drive shaft all the way through the front, and we have to make the power go to the front wheels,” Pearson said, adding that RR6’s suspension design was well optimized for handling, traveling, and taking big jumps, but it won’t work for RR7.
“The problem is that it does not allow for an axle. So, we had to adapt this design to fit an axle, and that’s why we needed to build a new car.”
But it’s not entirely new. The team has been able to take some things — like custom shocks built in-house — and incorporate them into the new RR7 design.
“Suspension is incredibly critical not only for traction, but also for handling,” Pearson said. “Honestly, it’s everything. How you tune your shocks is everything, as well. It’s also special that we’re designing and making our own shocks. Other teams don’t make theirs; they buy them.”
The team also places a high priority on real-world data collection as opposed to relying solely on computational models.
“It’s about always trying to find something to do better than anyone else,” Pearson said.
That attitude powers everything about UNLV Rebel Racing.
Pearson strives — and pushes his fellow teammates — to be first in every category, from acceleration and maneuverability to costing and, finally, the ultimate test of endurance: A four-hour racing event designed to totally obliterate a team’s car.
While this year’s rule changes have tested the team’s winning strategy, Pearson is holding out hope that RR7 will prove its mettle when it hits the track in Washington on May 31.
“We’re not starting completely from scratch,” he said. ‘We’ve built upon a lot of mistakes, and we’ve built upon a lot of trial and error. This car is made from blood, sweat, tears, knowledge, trial, error, and a little bit of luck.”