On NASCAR’s Next-Gen car, one of the most interesting additions is the underwing including a rear diffuser. In recent months, the underwing has come under some scrutiny, so much so that NASCAR removed it for a short track package test at Richmond in late July. This raises a question, should NASCAR get rid of the underwing on the Next-Gen car?
The biggest benefit of the underwing is that it produces downforce without using the body of the car. Diandra Leslie-Pelecky described why that mattered to NASCAR in an NBC Sports article in June of 2022.
Part of NASCAR’s design philosophy was increasing downforce without involving the body. That allows for a symmetric shape, and lets manufacturers add styling details that better evoke the street models.
Diandra Leslie-Pelecky of NBC Sports
This provides some insight into why the underwing exists, to begin with. However, there have been some unintended consequences. What are some of these unintended consequences?
One of the biggest issues with the Next-Gen car is the sheer amount of dirty air that the car has. The trailing car is constantly at a disadvantage because of the dirty air that comes off of the leading car, and the underwing produces a lot of downforce through aerodynamics under the car. As a result, there is a large issue with these cars following in dirty air.
Unfortunately, dirty air will be an issue no matter what type of car you run. The bottom line is that every race car nowadays is heavily dependent on aerodynamics, and there is no going back on that anytime soon. The rear diffuser may help somewhat, but, it’s hard to say it solves every problem the car has because dirty air is an issue no matter what.
Now, the underwing probably does not help because it forces the Next-Gen car to be so reliant on aerodynamics. However, it’s hard to say it would solve every problem. Then again, NASCAR tried it at the short track test in Richmond, and it seemed to produce decent results, so, maybe they are on to something.
The underwing, and particularly the rear diffuser causes the Next-Gen car to be incredibly low to the ground. As a result, towing the car has become a problem at times. Early on in the Next-Gen car’s life, the tow trucks struggled oftentimes to get the race car back to the pits without damaging the rear diffuser.
Another issue reared its’ ugly head with Joey Logano at Pocono back in July. This was more due to the flat tires than the underwing itself, but the underwing still does not help because of how low to the ground it is.
One way NASCAR can try to mitigate these issues is to get rid of the underwing and the diffuser, which gives them some more space to move a car to the garage or the pits if need be. It could also allow some drivers to finish races they could not previously because of damage to the car.
This one is harder to totally pin on the underwing itself, but, we have seen a terrifying Next-Gen flip at Daytona with Ryan Preece along with a near-flip by Brad Keselowski at Talladega last weekend. We even saw a flip, more so a blowover, in the first Next-Gen points race at Daytona, and David Land actually talked a little bit about how the flat bottom could have caused this flip at least somewhat.
He described how the flat bottom of the car can be a “big kite” if the roof flaps do not deploy and do their job the way they want to. Again, there needs to be some significant investigation before pinning these all on the underwing, but, it is something to look at.
The underwing is a part of the car that at least needs to be looked at by NASCAR. Does it need to be gotten rid of entirely like NASCAR did with the rear wing of the Car of Tomorrow? It’s tough to say that the situation has evolved to that point.
However, it is something to look at at the very least. Maybe making some major changes there could allow for some improvements to the racing product and maybe even safety.
