Nitro, short for Nitrous Oxide (N2O), is a part that can be installed on modifiable vehicles in the three available Mod Garages in GTA San Andreas. When installed on a vehicle, if the Nitro button is pressed, the vehicle's speed increases dramatically along with a motion blur effect. Bright blue flames spew out of the exhaust pipes when Nitro is turned on. Nitro is meant to give the player's vehicle a short burst of speed. After a few seconds the nitrous exhaust ceases and the vehicle may revert back to its normal top speed. A Nitro boost is followed by a delay that won't allow a player to use another Nitro boost right after a prior boost.
Tip: To know when you can fire a Nitro boost again is to look at the exhaust after a depleted boost. If the fumes are colored blue, the boost is still in its "delay" state. If the fumes revert back to the normal, grey fumes, then the Nitro is ready to be fired again.
All Mod Garages have Nitro as an available part. Nitro comes in three "strengths:" 2x, shown with a small tank; 5x, with a large tank; and 10x, with 2 small tanks. Each option determines how long you can use a Nitro boost.