F-1 Pole Position
Unlimited Fuel
In any grand prix race, set your fuel to 10% before starting to get max acceleration and dont worry- you dont lose any fuel during the whole race! you can go ten laps with out ever dropping below what you set it at, so put it on 10 for the acceleration.
Credit Goes To: Eiksirf via N64cc

 Unlimited Fuel
 Bonus Car
Extra Car
After you've become World Grand Prix Champion, turn on the system and hold A and B when the screen "Now loading the data from controller pak..." appears. Now go to the Driver Selection screen, and you'll notice that the '96 Forti drivers will now have an Ubi Soft Original H-RA V12 Car.
NOTE: You need a Controller Pak to enter this code.
Credit Goes To: Nancy Evans via N64cc