Sprint Car Adjustment Guide
Many times, new race fans refer to sprint car wings as "That big thing on top of the car". For the people who do not necessarily know, there are many things that the wings on our cars can do. They help the cars go faster, handle better, and even add a little bit of safety to the race car. Here, we will talk a little bit about how they work, and why racers run them.
Today’s sprint car wings are a 5’ by 5’ aluminum construction belly with two aluminum side boards. However, in the early days it was not uncommon to see guys making bigger wings, smaller wings, even wings out of Plexiglas or plywood! Basically, a wing on top of a spring car is an airplane wing turned upside down, with the same type of shaping that is used on your typical jetliner. The wings started gaining popularity around the early 70s, and they for the most part, became a staple in sprint car racing in the early 80s when Knoxville and many other race tracks mandated them. Below is an example of what a sprint car wing looked like many years ago, you can see how they have come a long ways!
Now that we know what the wings are, well, how do they work? Like I stated above, a sprint car wing is essentially an airplane wing turned upside down. So, instead of creating lift, it creates down force. The down force is created when the air moving under the wing, moves faster than the air moving over the wing. What this does is it creates a low pressure spot under the wing, and a high pressure spot on top of the wing.
Naturally, air wants to move from high pressure areas to low pressure areas, this is also the same principal that causes wind. With the high pressure area wanting to get to the low pressure spot, the air in the high pressure spot moves towards that direction, but the wing is in the way. The air now is trying to force its way through the wing, but it can’t go through the aluminum, so it simply pushes down on the wing creating down force.
The rules these days are regulated so much that it is hard to be able to do much with the wings, as far as the general size and shape. What teams can do however, is move the wing around on the car. If the track gets dry slick and you need to find grip, many teams will stand the back of the wing up. This creates more down force, as well as more drag on the car. When the track is heavy and sticky, a team will keep the rear edge of the wing lowered and keep it forward on the car to help free the car up. Keep in mind, more wing angle will help the car stick to the racetrack, however it will act like more of a wind sail, and create more drag than a wing that doesn’t quite have as much pitch.
The typical starting point for the top wing will be anywhere between 24-28 degrees, depending on the track and the conditions. The nose wing is usually even with the down tubes on the race car, which is approximately 30 degrees. My general rule of thumb on a short track is that you want to be able to lay a straight edge across both your top and nose wing and have it touch the front and back edges on both wings. In theory, that creates the most efficient air transfer from the front wing to the top wing. On a longer half mile track, I will typically drop the back of the top wing to reduce some of the drag with the higher speed track.
Drivers can even move the wing from the cockpit of the car as they are racing. During the race, if the car starts to get looser on the driver they will reach up and grab the wing valve, pulling the wing back. Sometimes a driver will get too happy with the wing valve and pull the wing back too far. If this happens, they will need to wait until a caution comes out to be able to move the wing back forward. That is, unless someone has a Sweet Manufacturing Steering system with their pump, valve, and ram. The Sweet system is capable of moving the wing forward at speed in most cases.
The adjustability of the wing is going to be your biggest adjustment period in a race car. Moving your wing back will most likely tighten the car up more than any adjustment on the race car will once the track goes away. Likewise, if you are trying to free up the race car, moving the wing back forward will be your biggest adjustment you can make to the car. For the most part, any other adjustability is outlawed across the board. The driver is only allowed to control the wing from the car front to back, and the crew can adjust the wing up and down while in the pit area.
The wings on a sprint car are the main reason behind the extremely high speeds of winged sprint car racing, and provide a great safety feature to the race cars. Speedway Motors has a variety of wings available to choose from for your sprint car. I would recommend the HRP Flat Top Wing Kit and the HRP Dish Top Wing Kit. If you have any questions, please do not hesitate to give us a call here at Speedway Motors, we are always happy to help you!