The term downforce describes the downward pressure created by the aerodynamic characteristics of a car that allows it to travel faster through a corner by holding the car to the track or road surface. The same principle that allows an airplane to rise off the ground by creating lift under its wings is used in reverse to apply force that presses the race car against the surface of the track. This effect is referred to as "aerodynamic grip" and is distinguished from "mechanical grip," which is a function of the car mass repartition, tires and suspension.

You may think that downforce has no effect on the handling of a Mini-Z but you would be very wrong as it makes a big difference in handling. The effect of downforce was driven home for us when we started racing a Pan Car Body and saw dramatic improvements in out lap times.

We love racing the Pan Car bodies, but unfortunately, the rules for the Mini-Z World Cup only allow Pan Car bodies to be used in the Pan Car class since it would represent un unfair advantage against regular bodies. In light of this we needed to quantify the effects of downforce that various bodies created to allow us to choose a suitable replacement. Our goal was to replicate the handling that the Pan Car body offered by doing research on the amount of downforce that various bodies, including the Pan Car body itself, produce.

To test this we needed a wind tunnel. We set up a makeshift wind testing rig that consisted of a see through tub with a small scale inside of it. We placed a piece of cardboard on top of the scale so it would be flush with the edge of the plastic box for minimum airflow disturbance. Our plan was to detect the difference in the weight of the body once it was on the scale and with a constant wind applied by a fan. This would show us if downforce/lift was present and how much was generated. First up was the Ferrari Enzo Auto Scale. Surprisingly, the weight of the body reduced by 3 grams under constant fan speed, meaning that an Ferrari Enzo body produces 3 grams of lift. When we put the Pan Car body under the same test, we saw no change in weight, therefore the body had 0 lift. These results were consistent with our experience on the track as the Enzo body tended to slip and slide around in corners, yet the Pan Car body stayed planted in corners like it was on rails.

In an attempt to mimic the Pan Car body’s characteristics we added a fairly large lip spoiler which was cut from the Lexan box sleeve that the Auto Scale Body Sets come in. This plastic is the perfect thickness and consistency for making wings. We secured it with Trinity 6000 Narrow Servo Tape to the rear deck. We were surprised to see that the simple addition of a wing completely solved our problem. The new lip spoiler provided an impressive 3 grams of downforce, which, in a car weighing less than 180 grams, is quite significant.

On the track, the car was now stable in high speed sections and very nimble through the chicanes. It was predictable during quick transitions in speed or direction. Before the addition of the lip spoiler, the Ferrari Enzo body was almost un-drivable on our Modified Team car, with poor traction and control. Now it is resolutely stable and my favorite car to drive.

Through our experimentation, we have learned that downforce is critical for an optimal setup and is easy to measure. You can test for downforce with everyday office supplies and apply it to your car own setup. This is a great way to make dramatic improvements in performance without breaking the bank.