A rare question related to how to play a game.
- (R)+(Dpad) to start drifting into a turn. Dust and maybe blue sparks should be visible.
- While drifting -- still holding (R) -- alternate between "←" and "→" on the dpad. The blue sparks should eventually turn red.
- Release (R) after the turn (red sparks must be present). A mini turbo boost should be the result (and the counter increases).
You must be successful on all turns in one lap to get the 4 mini turbos.
It requires some practice, but becomes natural after some time in normal gameplay.
Good luck!