To get the angle right, I found it easiest to line up if you hit the red booster on the turn, then hit the very start of the blue booster while red to slow down. Angle into the wall and jump. It's kind of a blind leap of faith to find the opening, but once you get it down, you can navigate the jump more smoothly.
There's also another shortcut (not shown in this clip) at the very start, where you can jump after the blue boosters, at the crest of the next hill instead. With the speed on laps 2 and 3, this gives you enough air to cut straight to the right and skip the entire wide turn.
by Shadowspaz