Boosting is powered by accumulated nitro. The juice fills slowly, but you can fill it far faster with Boost Feats. Boost Feasts are nitro bonuses given out for meeting certain in-game criteria. These include Jumper (for making longer than average jumps), and Sniper (for driving or flying through a narrow window or gap). It encourages you to drive recklessly, which I'm all about. http://naildbiter.com/8ZGd2