All you have to do is boost 20 times in a single race and win.
Select Gate Rally, easy difficulty against bots with the minimum 8 laps, it does not matter which map. Start the race and proceed to earn boost by flicking the
up, you can have 5 boost maximum at a time, so flip 5 times use the boost 5 times then repeat 3 more cycles for a total of 20. You must win the race for the achievement but it will not be difficult seeing as how you are boosting so much and will most likely overlap your opponents. Once you win the race the achievement will pop on the post-race screen.