Dirt tracks are known for tiny sprint cars with huge wings, but what about other forms of loose-surface racing? Why not rallycross?
Peter Dozeman owned a business building dirt track and circle track cars and applied that to the most eye-catching SCCA rallycross Mazda Miata build I’ve ever seen. In case you haven’t noticed, there are wings. The wings are big.
And yes, they’re functional.
“I like the modified class because there are very few rules,” Dozeman told The Drive. “And I read the rule book.”
There’s are only 11 rules for the modified rear-wheel-drive class, and that eleventh rule was added to clarify (and allow) something Dozeman did with the Miata in a previous year.
“Aerodynamics are not restricted,” Dozeman continued. “It’s wide open. You can do whatever you want.”
The Miata’s first race in its current spec was in last weekend’s SCCA Rallycross Nationals, where Dozeman took second in the modified rear-wheel-drive class and his codriver Brianne Corn took the class win.
Dozeman had been racing the Miata for four years and working with Corn on the car for a while now. “It’s dependable and very simple to work on,” he said of the car. This wasn’t the Miata’s first run at SCCA Nationals, either, although it was the first time the car itself may have gotten more attention than its Nationals win.
It was Corn who ultimately had the hook-up on the wings. Dozeman ordered aero from England that wasn’t going to make it in time for Nationals, but he remembered Corn’s old B-Mod-class autocross racer that had plenty of aero.
Dr. Bob Woods at the University of Texas at Arlington had made the B-Mod car’s wings, so that’s who the duo roped in to finish out the Miata’s aero. Dr. Woods heads up the Formula SAE program there, and students helped design and prototype the Miata’s wings. They couldn’t test them out in a wind tunnel, but they did have access to computational fluid dynamics programs that could simulate how the wings would work in real life to test out different tweaks.
So, it was the UTA autoclave to the rescue. The FSAE crew not only delivered on time, but they handed off 14 pages of instructions on how to install the wings. They essentially delivered a full kit, complete with spare parts and exact directions on where and how to install the wings. They even added tuning instructions.
The great thing about huge wings is that the faster you go, the better they work at sucking the car down to the ground and the faster you can go.
“Once the aero starts working at about 40 or 45 miles per hour and up to 60 or 70 [mph], it’s supposed to be generating about 500 pounds of downforce,” Dozeman explained.
“It’s pretty well balanced,” he continued. “I’d like to get a little more on the front so my turn-in doesn’t push [forward, as in understeer], but we didn’t touch it all weekend because that was the first time we raced it. It was going well enough that we didn’t want to go backwards by making a change. So, we left it alone per their instructions.”
Underneath the largest wings I’ve ever seen at a rallycross event is largely what you’d usually expect in a top-class grassroots rallycross build. The team removed every spare pound they could, getting the car’s overall weight down to roughly 1,650 lbs. The roll bar, which isn’t mandated for rallycross, got ditched in favor of shoring up the roof and the rest of the car’s pillars with 3M body panel foam. That roof is now permanently attached with epoxy and rivets-no fiddly, heavy hardware here.
The freshly built engine, built by Rossini Racing Engines, is a 155-horsepower naturally aspirated build with higher compression than stock. The engine itself was moved back about two inches.
It’s still a rallycross build meant for the especially bumpy SCCA Nationals site, so there’s nine inches of front and rear suspension travel. They used spherical bearings from Keisler Automation instead of rubber bushings, as rubber bushings wouldn’t allow them to have the amount of suspension articulation they wanted. Plus, rubber has extra wiggle room that they didn’t want. Robby Bilbrey at Race Products Inc. also built a set of Bilstein shocks to fi…