Boost

Boost is one of the primary game mechanics in the Burnout series and is present in all games. For as long as it is active, the player's vehicle has improved acceleration and top speed.

Throughout the games, the player's current boost level is indicated by a bar in the bottom left of the screen known as the boost bar. Performing actions such as drifts, near misses, and air time fills the boost bar, while using boost drains it. In Burnout and Burnout 2, boost can only be activated when the bar is full and refills either partially or fully when emptied; refilling it fully is called a Burnout. In Takedown, Legends, and Revenge, boost is activated on demand and the bar is extended by taking down opponents or depleted by crashing. Dominator uses a mix of both systems while in Paradise, either system may be used depending on the vehicle's boost type.

Prior to Burnout Paradise, Boost is activated by pressing and holding the R1 button on PlayStation, the A button on Xbox, or the R button on GameCube. In Paradise, boost is switched to the cross button on PlayStation and the left shift key is used by default on PC.

= Burnout, Burnout 2 = Boost in the original Burnout and Burnout 2 is not usable until the boost bar is completely filled. When activated, the soundtrack fades out in the original game and the mix changes in the second game. Fully depleting the boost bar results in it being refilled by a certain amount depending on the player's boost earning actions. This is called a Burnout. If the boost bar is fully refilled and fully reused, it results in a Burnout chain. If boost is deactivated at any time, it does not refill. Crashes also deplete the boost bar.

= Burnout 3, Burnout Legends, Burnout Revenge = Boost in Burnout 3, Legends, and Revenge can be activated at any time provided there is boost available. In addition to the prior games' boost earning actions, takedowns fill the boost bar and, if not yet at the maximum, extend it up to x4 length. Similarly, crashing or being taken down shortens the boost bar. There are no Burnouts, so when the boost bar does not refilled when empty; the player is expected to refill it via boost earning actions.

= Burnout Dominator = Burnout Dominator uses a mix of the prior entries' boost types called Dominator boost. Like in Burnout 3, boost can be activated at any time as long as there is boost in the boost bar, but it does not lengthen or deplete when crashing. When the boost bar is filled, it turns blue and takes on characteristics of the boost used in Burnout 2, allowing for Burnouts and Burnout chains to be performed. This mode is referred to as supercharge and depletes faster than normal boost.

= Burnout Paradise = Boost in Burnout Paradise is split across several boost types which vary depending on the vehicle being used. Like in prior entries, flames are emit from the exhaust when activated. The color of these flames depends on the type used.

Though each boost type is used on a particular type of vehicle, the type itself does not impact any attributes of the vehicle. This has been proven in gameplay by mods such as the Vanity Pack, which allow boost type to be switched on the fly.

Speed
Speed boost, originally called Danger boost and internally called, is functionally identical to the boost type used in Burnout and Burnout 2. In addition to other earning methods, boost can be earned by smashing props around Paradise City.

Unlike in Burnout and Burnout 2, flame particles are emit from the exhaust pipes when activated. These flames are yellow and, prior to version 1.6, would begin forming smoke trails as the boost ran out.

Aggression
Aggression boost, internally known as, is functionally identical to the boost type used in Burnout 3, Legends, and Revenge, with the exception that it can only grow to x3 rather than x4.

Aggression boost is orange in color and, like Speed boost, would form smoke trails when about to run out prior to version 1.6.

Stunt
Stunt boost, internally called, is similar to Aggression but does not lengthen or shorten with takedowns and crashes, instead maintaining a constant length. It was altered after version 1.0 such that it could be stopped immediately after starting to boost, whereas the other types keep boosting for a short time before stopping.

Stunt boost is green in color and does not have smoke trails prior to version 1.6 like the other types do.

Development
During development,  was functionally the same as Dominator boost, where boost was usable at any stage and would turn blue when filled, becoming capable of performing Burnouts. This type is the only one present in Burnout 5 (2007-02-22 build).

Unverified rumors, citing an anonymous developer, claim this was originally developed for Paradise and was scrapped after EA UK co-opted it for use in Dominator. The type was not present in Paradise in in 2006 and it is not clear how this would have been achieved in such a short timeframe.

None
Boostless vehicles include the Hunter Olympus, Nakamura Rai-Jin Turbo, and all bikes. As the name suggests, boost is not present on these vehicles, though the two cars gain a grey boost bar when entering Showtime. Bikes use leaning forward as an effective replacement for boost, gaining both acceleration and top speed by doing so but limiting their turning capability.

Locked
Locked boost is used on the Carson Extreme Hot Rod. When activated, it locks on and never runs out. The only way to deactivate it after activation is to slow down with the brake or handbrake.

Switchable
Switchable boost is used on the Montgomery Hawker Mech. Pressing L3 on PlayStation, LS on Xbox, or the siren button on PC switches between speed, aggression, and stunt boost. The size of the boost bar may differ from the normal types.