The art of NASCAR’s 3D printing performance advantage

Racing is all about innovation and finding any advantage over your competitors. Sometimes that comes in the form of employing a better driver, a faster pit crew, or a genius engineering team that can successfully play within the margins of the rule book. We saw an example of that with Formula 1 this season and its flexi-wings that brought speed for various teams. And the FIA swiftly began clamping down on those that were playing in the gray areas of the rules. Similar things happen in every level of racing, and because teams continue to test the limits, much like F1’s rule books, theirs too, continue to grow a little more every year. 

Finding those tiny advantages outside of the prescribed parameters is tough when you’re working with a spec car such as NASCAR’s Next Gen car, but top flight teams — like Joe Gibbs Racing — have been finding a way using modern technology. Specifically, 3D printing.

Previous generations of the NASCAR Cup car allowed teams to take a variety of components to test days or the wind tunnel to see which ones offered the best balance of aerodynamics, but outlined limitations on testing and the introduction of more spec parts meant that teams had to get creative with how they chased performance. That same mentality still applies to  NASCAR’s Next Gen model, which requires Cup teams to utilize even more spec parts when assembling their cars, but there are still components teams are able to produce on their own. Most of these parts appear inconsequential — things like brackets or covers for covers that are unseen. Creative engineers and fabricators quickly turned to enhancing those inconsequential parts via 3D printing.

Something as simple as 3D printing offers teams an opportunity to quickly mock up and print components that can be used directly on the cars if teams predict an advantage. For instance, Joe Gibbs Racing has always been on the forefront of 3D printing, employing machines from Stratasys for over 20 years to print these types of parts. One of those components was a pass-thru duct — a piece that sits behind the driver which is intended to channel air from the rear quarter windows into tubing that leads to the rear suspension area in order to cool things like the brakes or transaxle. JGR engineers figured out that the pass-thru duct also has an indirect effect on the aerodynamics of the car, so they printed several versions of that duct with different widths and different radii of bends to improve aerodynamic performance.

On a recent visit with JGR, I was able not only to see their Stratasys Fortus 450mc and F370CR printers in action, but meet with Matt Faulkner, who leads the organization’s additive manufacturing team, to see some of the components that they’ve been able to build over the last few years, ranging from tools to parts that actually run (or have run) on the cars in race scenarios. 

One of the unsuspecting parts they’ve modified is the sideview mirror, which gets mounted on the tubing at the front of the drivers window, isn’t a standout part to change to gain any sort of speed advantage. However, it is yet another area where JGR has found aero advantages, and can make an enhanced part for thanks to NASCAR’s rules that leaves that part open. Their engineering team was able to develop the shape of the mirror in order to maximize downforce.

A rendering of the OEM-approved brake duct zones.

Photo by: NASCAR

Another area where they were able to find downforce was in the brake ducts that sit in the front bumper of the car. NASCAR limits how and where the brake ducts can be placed but the actual design of the brake ducts is open.Faulkner shared that this has been a big area for teams to find aero advantages and is so useful that some teams have been running brake ducts at tracks that didn’t require them just because of the benefits. NASCAR caught onto this method and included language to limit the tracks where brake ducts can be employed as part of the first rules update for the 2025 season. They are now specifically banned from larger tracks like Charlotte Motor Speedway and Talladega.

These 3D printers allow JGR to print fairly large components like the inlet duct that is used for the transaxle cooler in the rear of the car. Yet another part that NASCAR leaves open to the teams (with some recommendations on how to build it). Some teams make carbon fiber versions to use at a variety of tracks, while teams like JGR will print a variety of versions made of different materials and polymers designed specific to each track to efficiently cool the transaxle and maximize aerodynamic performance for the unique demands of that track. The ability to quickly print multiple versions of something like that duct also allows them to test different configurations among their cars during the very limited practice sessions to find the most optimized variant. Almost all of the parts that end up being used during racing conditions are printed using FDM Nylon 12CF which combines nylon 12 base polymer with chopped carbon fiber.

Photo by: NASCAR

JGR’s FC370R printers also provide the ability to print using flexible elements like Thermoplastic Polyurethane (TPU) — a special type of malleable and flexible plastic that is often found in things like footwear or phone cases — which makes it stand out since it can be used in applications where stiffer plastics might not be ideal. Faulkner explained that his team can build customized attachments for their tools like shoes for the clamps that they use to hold body panels in place when assembling a car. Although these body panels are spec parts, the assembly team can use these customized clamps to hold them in a specific position during assembly to manipulate the shape of the body and optimize aero for a specific type of track. 

“We’re making these not only for durability but we’re making these in custom shapes so that the particular things we’re clamping together like if you’re clamping two tubes together, the tendency of a flat pad is to slip off,” Faulkner said. “Well, now we can print those in different custom shapes to clamp together what we need to try to squeeze more speed and shape out of the cars.”

Fans often wonder how there can be such distinct differences in performance in the NASCAR Cup Series even though every team works with the same spec car (outside of the powertrain). The easy answer is that it’s just a matter of who has more resources. All of that starts with smart engineers and fabricators. But also having the financial and material ability to use additive manufacturing to create parts, especially on demand, allows these teams to efficiently tool and tune many of these components to gain them any little bit of advantage on track, until they can’t use it anymore. And then it’s on to the next component and advantage.