There are mainly 3 types of chargeable boost in this game, boost start, drift boost and stunt boost.
Boost starts appears to be glitched at the moment. you can see it in the other topic.
Drift boosting has 3 levels and it is determined by the length of your drift and the amount of gas applied during the drift. All drift boosts are activated roughly 0.5 seconds after the release of the brake button. Level 1 boost (the weakest boost) takes about 2 seconds to charge. There is no indicater on the screen to indicate a level 1 boost but you can see it from the exhaust pipe of the vehicle and the sound it makes.
Level 2 boost takes longer time to charge roughly 5 seconds. Again, all timing is calculated based on the amount of gas applied during a drift. to get to level 2 boost, you ignore the activation of the level 1 boost and continue to drift further. There is a small indicator on the right of the screen to indicate you have reach level 2 boost.
For level 3 boost, you drift as long as possible, skipping both the level 1 and level 2 boost cues. Expect to take roughly 8 seconds of drifting for a level 3 boost. You can also see a huge indicator on the screen telling you that your level 3 boost is ready.
For stunt boosting, each trick you perform while in air-time gets you 1 boost level if i'm not mistaken. so in theory, 3 consecutive stunts gets you a level 3 stunt boost. Again, this is open for debate as I don't fine stunt boost as fast as drift boost, leading me to believe drift boost takes priority over stunt boost. All stunt boost activates the moment your vehicle touches the floor. If your in the middle of performing a stunt and you touch the floor, you will fail your stunt and all boost you have will disappear and your vehicle will stall slightly. Don't let this happen.
Another thing to note about stunt boosting is that you can do 4 tricks while air-time. The game will acknowledge you have done 4 tricks and will display it. But i'm not sure if the boost you get from doing 4 tricks is faster than the one where you do 3 tricks. --- Driving a PC racer with the keyboard is about as effective as typing an e-mail with your car's steering wheel. ~ Brian Ekberg
Stunt boost and drift boost have the exact same affect. And on certain stages you can get up to at least 7 stunts before landing. The power of your boost won't be greater than 3 stunts when you land but, the announcer will say something different for each stunt performed after landing. And on the Dream Valley stage, if you boost thru the orange rings, your speed greatly increases as long as you pass thru the rings. Alot of people don't know this. --- I'm 2nd. to God's power. I'm the semi-supreme being. XBL Gamer Tag: AboveOmnipotent