The nitrocar mod applies to the Scorpion and Hellbender.

Fire toggles the nitro mode. When on, the exaust will flare. A nitroed car has a massively overpowered engine, sacrificing stability for sheer speed. It'll go very, very fast, but takes practice to handle at such speed.

Additionally, a nitrocar destroyed while nitroed will explode with redeemer-level force, or if left abandoned long enough. This makes it an effective suicide bomb if driven into walls. Friendly fire from the last player to occupy the vehicle will cause damage, so you can remote-detonate in that manner when an enemy comes near, or abandon it next to a powernode or core.