Some people might say that NASCAR is just cars going around in a literal circle for a few hundred laps but not many understand the engineering marvel that each one of those cars are. One of the more important and perhaps even confusing parts of the Next-Gen car is its diffuser. It’s visible from the rear on the floor but what does it exactly do that the floor doesn’t? That’s where Stewart-Haas Racing came in with a simple but eye-opening explanation.
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“A diffuser is a carbon fiber composite that starts just ahead of the rear wheels. It is the closeout piece between the underbody and the rear of the car. The diffuser has vertical blades called strakes that help air flow out from under the car. This is called a Venturi effect, allowing air to easily flow out under the car. The strakes created a swirling motion that hurries air out but also helps draw in additional air to create more downforce,” a video uploaded by the team’s YouTube handle said.
Remember when NASCAR came out with their new aerodynamic package to improve racing on short tracks before the season began? One of the biggest changes to the car in that package came in the form of the diffuser. As per a report in USA Today, the diffuser was simplified with a fewer number of the vertical strakes that help with the passing of airflow underneath the car.
How does a smaller diffuser help in short-track racing?
In an earlier video released by NASCAR, Letarte compared the floor used for the earlier season to the one used in short track races this year. The striking difference between the two is the size as the updated one was a lot smaller than the one normally used. A simplified diffuser, in this case, meant that it was shorter and narrower with fewer strakes. This was done to allow drivers to slide around the short tracks and make passing on the racetrack effortless.
But there’s an issue with a smaller floor and diffuser, lower downforce. If there’s no downforce, grip is going to be hard to find. To combat that, NASCAR decided to increase the length of the spoiler from two to three inches. In a sport of such fine margins, that is a big change but the results have been hard to come by on track.
Yes, the Bristol race was exceptional but that was due to tire wear more than anything. Almost every other short track race has been more of the same which once again proves that a lot is left to be done. Maybe a bit of horsepower would go a long way in solving that, according to probably every single driver in the Cup Series right now.
