It is a modified version of the Winchester P94 plasma rifle. The plasma bolt chamber has been hotwired to accelerate the bolt formation process, resulting in an increase in the rate of fire.[1]
The turbo electric plasma rifle is a upgraded version of the electric plasma rifle, and is found only in the Secret Vault. It is to be manufactured using technology contained in the Secret Vault. It is equipped by the most important super mutants of Attis army and by the champion of the Gladiator Pit in Los, the wasteland stranger.
References
↑In-game description for the turbo plasma rifle in Fallout and Fallout 2. [1][2]