Go to
Practice, then
Solo Run and choose the
Mansion map. Continue forward until you notice a boost pad and an airstream. Stand in the boost pad to fill your boost to max. Use the airstream and swing on the small platform above. Swing back and forth to gain momentum and speed until a small shadow effect appears behind you. Now, swing to the left, use your boost and you'll easy enter super speed for at least 3 seconds. The achievement now unlocks.