The Chaparral 2J,also known as the ‘fan car’, and also the ‘sucker car’, was the first of only a few race cars to feature fan-assisted aerodynamics. Built during the 70’s, the car was basically a giant racetrack vacuum-cleaner; a movable skirt underneath the car sealed in the vacuum created by two large fans mounted at the back (thus the name “fan car” and “sucker car”).
The 2J was powered by a chevy v8 that was tuned to push close to 700hp. The owner,Jim Hall, also decided to add a snow mobile engine behind the car. The two 17-inch diameter fans were powered by a single 45hp, JLO Rockwell snowmobile engine, which ran at constant speed.
This means that the downforce was always constant at any speed compared to aerodynamic downforce which varies with the car’s speed. The car competed in the Can-Am series which had no max displacement so the snow mobile fan engine was unaffected.
However, like any other insane ideas, the “Sucker” was too good to last. the competitors had no ability to compete with the car, so the FIA quickly found reasons to remove the car from the racing scene.They formulated that the sliding skirts were found to violate aerodynamic rules. They assumed also that the fan assembly had a tendency to suck up debris from the track and spit it back at drivers in the rear -which basically is where other race cars usually ended up, behind the 2J.