Racing Refresh Tech Tuesday: NASCAR Next-Gen Aerodynamics

(Image via NASCAR)



With the advent of NASCAR's next generation of race car to set the foundation for the future of stock car racing in America, the car itself has a myriad of new changes and specifications that NASCAR has never seen before. From the 18-inch diameter tire and center-locking lug-nut that are some of the most obvious changes to the car, another introduction to help the on-track product in the series is the introduction of new aerodynamic components on the car.



Since 1959, aerodynamics influenced stock car racing even though drivers and crew chiefs did not really grab the concept until the late 60s. But until the end of the 2000s, NASCAR took most of its aerodynamic advantages from the body work of the car with the front valance and rear spoiler. Then with the introduction of the COT and Generation 6, cars would have such a low ride height that cars would effectively seal off out side air from the underside of the car


Over the past couple of years, the term "dirty air" and "aero push" have become buzzwords when the series heads to intermediate and superspeedways of late. The idea that cars traveling behind a car have a dramatic loss of downforce which hurts close racing. Whereas in the past, aerodynamic influences have been on the actual body of the car and punches a hole in the air so big that once someone catches another, the battle stalls out leading to less than glamorous racing



With the Next-Gen car, most aerodynamic load is actually underneath the car with the advent of the stepped splitter and rear diffuser. Unlike in the two previous generations of NASCAR race car, the new stepped splitter is a revolutionary piece of kit that in my opinion is the start of the three most important parts of the new car.


To start, the splitter does not create downforce by itself. With a hypothetical velocity of air as 1, lets go forward with my explanation.


So V1 air hits the front splitter of the car. The majority of the air goes around and above the car following the body of the vehicle. The air that impacts the splitter slows the car down due to aerodynamic load and creates a pocket of dead air with a velocity of 0. But with the stepped splitter, air is allowed to go underneath the car. This air is squeezed between the car and the ground. Because the air does not change in volume, physics forces that air to move faster to a velocity of 2. With slower air moving over the top of the car and faster air moving below the car, the aerodynamic load from the air makes the cars have increased grip and traction.


Congrats you have downforce.


Now the problem. The underside of a Next-Gen car is completely sealed off due to a carbon-fiber under panel which allows air that moves under the car to gain velocity and cause more turbulence and wake. (Mercedes F1 Team, you reading this) . If you are in a car behind our lead car, Your initial contact with air is at V2. Air over the top of the car is slowed to V1. Air under the car is is at V2. Your downforce is less effective as the car in front.


Adding the diffuser to the rear slows V2 air to V1 air. Allowing the downforce of the following car to be more effective. It also allows air to be redirected in a vertical trajectory to allow trailing cars to not be effected as much due to a loss of downforce

`Now diffusers in motorsports aren't a new concept in series like IMSA, IndyCar, and Formula One. But to the world of NASCAR it can seem at times to reinvent racing all together. I see the criticism on NASCAR's various social media pages all the time. Fans saying "these cars ain't stock no more...", poor English aside, NASCAR hasn't been stock really since the inception of the series, with engineers modifying parts to make cars go faster ever since cars took to the sandy shores of Daytona Beach.


To the critics of the new aerodynamic changes, the on-track product has been so much better then what we have seen in previous years. As of writing, we have had fourteen different winners in the Cup Series to date in the 2022 season. The average margin of victory is the closest it has been in years and green flag passing is at an all time high. It is never a bad thing to change, especially if things that change are for the better. When NASCAR does well, every other motorsport benefits from it. I for one couldn't be happier



Thank you for joining us on another edition of Tech Tuesday. This article has been released later than usual as I have had a death in the family. My grandfather, Henry Bestor passed away on Saturday. Henry was one of the men in my life that ignited an interest in motorsports and set myself on my professional journalism career. Henry lived a fantastic 96 years on this planet. He served in the Army during World War II. He helped man reach for the stars and land on the Moon as he was an engineer during Project Mercury, Gemini, and Apollo space programs. He lived a life most men won't ever live and I'm grateful of the contributions he made on my life and for all mankind. This edition of Tech Tuesday and each one for the rest of the season will be dedicated to him.





First mock-up of Mercury spacecraft, 1959 at McDonnell Aircraft. St. Louis, Missouri

Henry is the second from the left in the back row