To access the cheat mode, first press CTRL-TAB when a race has started. This will bring up a slidey puzzle game which needs to be completed. When this has been completed, CTRL-TAB will remove it from the screen. Now enter any of the following codes during gameplay:
Alt-F1: self destruct
Alt-F2: enemy sweep
Alt-F3: max fuel
Alt-F4: max ammo
Alt-F5: max shield
Alt-F6: add lap
Alt-Y: autopilot on
Alt-C: autopilot off