Yahoo Autos These Cheaty Scoops Are What Really Made the Dodge Charger Daytona Spectactular
Whenever people look at the winged cars from Chrysler–the 1969 Dodge Charger Daytona and the 1970 Plymouth Superbird–they often don't pay too much attention to the pair of rear-facing scoops which sit squarely in the middle of the top of the fenders. After all, the huge wing and the nose cone are the real features of the car. But, what is the deal with those scoops? At the time, Chrysler told anyone who would listen that the scoops were for tire clearance.
On the street version of the Superbird, there was nothing beneath the scoops so they served no function. The street Daytona had small holes cut beneath the scoop; air could pass through them but they added no tire clearance. The racing versions of the cars, however, had large holes cut out beneath the scoops. And, they served a distinct function that had nothing to do with tire clearance.
The tire clearance story had to be told to keep NASCAR's Czar, Bill France, from deeming the cars illegal. At the time, NASCAR rules only allowed body modifications for certain situations, one of which was for tire clearance.
In wind tunnel testing conducted by Chrysler during the design phase of the car, engineers tried a variety of modifications and made careful note of the effect of each modification, by itself and then in combination with the others. Nose cones were tried of varying shapes and sizes. They likewise tried out different wing setups. Somewhere along the line, they tested the effect of cutting holes in the fenders and placing air extractors over the holes.
The bulk of the design of the Daytona–and then the Superbird–was aimed at getting the air in front of the car to go over and around the car. Air that went under the car was a problem: it created a situation where the car lost traction. And the air under the car was "dirty." That is, the top and side surfaces of the car were smooth and blended together. The underside of the car was cluttered with exhaust pipes and tubing, suspension and the lower extremities of the engine. Air that went beneath the car or into the engine compartment slowed the car down. The exhausters relieved some of this pressure build-up by giving the air somewhere else to go.
The results of the various aero treatments were duly noted in internal memos drafted at Chrysler–memos that would not come to light until many years after these cars were retired. A "long" nose decreased drag by 9.5 percent, a "short" nose decreased drag by 12.5 percent. "Exhausters" mounted over the front tires reduced drag by a further three percent. The final "Package" recommended to the higher-ups listed the "short nose," along with "exhausters on front fenders," with the notation that this package, along with the wing and other modifications, would deliver a drag reduction of 19 percent. The original goal of the program was to find a 15 percent reduction in drag, so the numbers had been met with room to spare.
One aerodynamicist told me, "The least amount of air you get underneath the car, the better off you are." Of course, at the time, the Chrysler designers insisted that the fender scoops served no purpose other than to allow for more tire clearance.
Dodge, its drivers, and everyone who was in a position to know stuck to the party line that the scoops and the holes they covered were merely to allow tire clearance at high speeds. Even so, some people figured it out. One magazine reviewed the Superbird before the 1970 model launch, describing the scoops as "air exhaust ports . . . to relieve air pressure buildup behind the front spoiler."
Amazingly, Chrysler even occasionally let the secret slip. While they told the press and NASCAR that the scoops provided tire clearance, the scoops were referred to as "fender cooling vents" in sales materials sent to Dodge dealers. Which was closer to the truth. But not quite.
The beauty of it was that the scoops were in plain view of every other race team at the track, none of whom thought to copy the design unless their tires were bottoming out in the corners. Strangely, that wasn't a common complaint with other brands of cars–and if it was, why hadn't anyone else chopped holes in the tops of their fenders for tire clearance?
Steve Lehto is a writer and attorney from Michigan. He specializes in Lemon Law and frequently writes about cars and the law. His most recent books include Preston Tucker and His Battle to Build the Car of Tomorrow, and Dodge Daytona and Plymouth Superbird: Design, Development, Production and Competition. He also has a podcast where he talks about these things.
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