After heading down the road to score time on a local Dynojet, John tickled the keys on his laptop until he netted 501 hp and 490 ft-lb of torque, with the twin-turbo GN maxing out at 20-psi boost. | 
That was an improvement of 128 hp and 74 ft-lb at the wheels from the previous pulls with a single TE62, 24-psi boost, and comparable downpipe/intercooler combo (but with the benefit of XFI). The power improvement was across the board, from the lowest rpm to its 5,200 to 5,500-rpm peak. |
Due to the GN's stock bottom end, John tried to keep both the tune and boost fairly conservative. At WOT, the air/fuel ratio hovered from 10.75:1 to 12.00:1, averaging out to the 11.5 target. The intake air temps stayed a consistent 80 to 81 degrees on the dyno. Spark was kept at 24 degrees at WOT, and the injectors never surpassed 62 percent duty cycle. | |