To unlock this achievement you must win the Radiator Springs GP race in the game. This is a two lap race that has you traverse through Radiator Springs.
This race will be unlocked in Chapter 4 once you finish the Smasherville Race.
I don't think any of the races are that hard to do but if you want to make things easier and faster I would suggest using the cheat codes (you will still get your achievements). I recommend only doing "VROOOOM" and "IMSPEED" since I am not sure if the others affect achievements and they will not help you at all. The cheat codes are found here:
http://vgstrategies.about.com/od/xbox360cheatsc/a/CarsC....htm