July 26, 2009
Race Oddity: Chaparral 2J "sucker car"
Written by Ian Rothwell
Texas racing driver, team owner, and oil man, Jim Hall had become rather succesful in the Can-Am series by the time the Chaparral 2J was put on the track. Hall and his Chaparral cars had become known for pioneering aerodynamic developments from the start and the 2J of 1970 was perhaps the most advanced - if not outlandish - of the time.
The Can-Am series was a perfect test-bed for new ideas as the rules were extremely open to design variances. As Hall already knew, aerodynamic downforce was extremely important to keep a 700+ horsepower race car sticking to the track. Chaparral's previous models had sprouted wings and air-dams already though the 2J sort of "went to hell with the joke".
To create downforce, the 2J used a 2-stroke snowmobile engine to power two large 17 inch fans which literally sucked the car to the track. The suction was comperable to adding 1000 lbs of force to the car's tires. The car was skirted with Lexan to create a seal between the underside of the chassis and the track. The fans ran at a continuous speed, and therefore the downforce of the car remained nearly constant at all times regardless of the speed of the car.
To actually drive the wheels, a Chevrolet ZL-1 Corvette V8 was mated to a three-speed semi-automatic gearbox which was essentially a manual with torque converter rather than a clutch. It was rather similar to Porsche's Sportomatic transmission. Between the massive power and the massive downforce the 2J was a remarkable force to be reckoned with. Though extremely fast, the Achilles heal of the car was reliablity. Despite this, the potential was there, particularly with Jackie Stewart behind the wheel and McLaren in particular was not pleased. Due to complaints from that team, and others, that the car's fans kicked up debris from the track and als violated the rule banning 'movable aerodynamic devices' the SCCA outlawed the car. 1970 was the only season the car competed.