But the success in the long-distance races hid the shortcomings of the Lola chassis and Hall decided to take one last stab at car-building. He commissioned up-and-coming designer John Barnard to realize his vision of a new kind of Indy car based on the ground effect principle introduced on Colin Chapman's Lotus 78. The resulting Chaparral 2K, nicknamed the “Yellow Submarine” thanks to sponsor Pennzoil's brand colors, changed the face of Indy car racing. The first Indy “tunnel car” dominated the 1979 Indianapolis 500 in Al Unser's hands until sidelined by a transmission issue. It came back the following year and not only won the 500, but captured the 1980 CART PPG Indy Car World Series championship as well with Johnny Rutherford at the helm.