Set a record lap time one any track. Then, enter one of the following names at the lap record entry screen to activate the corresponding cheat function:

All tracks

Enter "TEAMPEEP" as a lap record name.

All Grand Prix Challenges

Enter "IMHRACING" as a lap record name.

Ace difficulty setting

Enter "REDJOCKS" as a lap record name. Alternately, successfully complete championship mode to unlock the "Ace" difficulty setting.