Chaparral 2J

Lore & Background

The 2J was the most unusual Chaparral. On the chassis' sides bottom edges were articulated plastic skirts that sealed against the ground. Two fans adapted from a military tank's ventilation system were housed at the rear, driven by a separate two-stroke engine. The car had a skirt made of Lexan extending to the ground on both sides, laterally on the back of the car, and laterally from just aft of the front wheels. It was integrated with the suspension system so the bottom of the skirt would maintain a distance of approximately one-quarter inch from the ground regardless of g-forces or anomalies in the road surface. The skirting produced a zone within which the fans could create a vacuum producing downforce on the order of 1.25 to 1.50 g when the car was fully loaded. Tremendous gripping power and greater maneuverability at all speeds were produced. Since it created the same levels of low pressure under the car at all speeds, downforce did not decrease at lower speeds. The 2J competed in the Can-Am series and qualified at least two seconds quicker than the next fastest car, but mechanical problems limited its success. It only ran in the 1970 season, during which it was outlawed by the Sports Car Club of America (SCCA). Although originally approved by the SCCA, they succumbed to pressure from other teams who argued that the fans constituted 'movable aerodynamic devices'. Sanctioning body FIA had banned such devices beginning with the 2E. There were also complaints of track debris sucked in and exhausted by the fans, hindering or even damaging the chasing cars. McLaren argued that if the 2J were not outlawed, the Can-Am series would be ruined by its dominance – though McLaren had been dominating since 1967.

In Their Own Story

The pits fell silent as the crew prepared the Chaparral for its final run. The air smelled of high-octane fuel and hot rubber, thick in the California afternoon sun. Dan Gurney climbed into the cockpit, checking the gauges that monitored the vacuum system beneath his seat. With a nod to the mechanics, he engaged the fans. A low hum vibrated through the chassis as the car seemed to flatten against the asphalt, gripping the tarmac with unnatural force. As he accelerated down the straight, the sound was not just of an engine, but of air being sucked from the world itself.

Reader's Guide

The Chaparral 2J only had three gears, being fitted in an automatic transmission, with the first gear providing 110 kilometres per hour (68 mph). The engine overall was capable of producing 680 brake horsepower (510 kW) at 7,000 revolutions per minute, with the max speed of roughly 360 kilometres per hour (220 mph). The weight of the 2J was under 1,800 pounds (820 kg).

Did You Know?

• The fans were adapted from a military tank's ventilation system and driven by a separate two-stroke engine, not from the tank's engine.
• The car's skirts maintained approximately a one-quarter inch gap from the ground regardless of road surface or g-forces.
• The 2J was outlawed during the 1970 season because its fans were considered movable aerodynamic devices.