Enhanced warp drive was the term used in the 24th century of advanced warp drive propulsion technologies that allowed a starship to reach and sustain extremely high warp factors and travel quickly between distant parts of space. (VOY: "Course: Oblivion", "Equinox, Part II")
In 2375, the Silver Blood biomimetic lifeforms invented an enhanced warp drive based on modifications to the class 9 warp drive technology of a Federation Intrepid-class starship. In the isodynamic design of the enhanced drive, the dilithium matrix was active and running hot all the time and the deuterium manifolds were never opened wider than 600 microns. The dilithium matrix and the isolitic converter had to be monitored constantly. A new type of subspace radiation was emitted by the warp drive that affected the whole ship.
The drive could be in constant active operation for years at a time, allowing a starship to safely reach and sustain extremely high warp factors, crossing from the Delta Quadrant to the Alpha Quadrant for example in only two years, eleven days and six hours. A warp field was emitted from the warp core itself. In main engineering, the subspace radiation produced by the core was at its highest level. While exposure was safe for Humans, other humanoid lifeforms and all the systems of an Intrepid-class starship, it had the effect of destabilizing the molecular cohesion of Silver Blood, causing its molecular bounds to break down. (VOY: "Course: Oblivion", "Relativity")
The modified warp drive powered by nucleogenic energy, invented by the crew of the USS Equinox stranded in the Delta Quadrant in the 2370s, was also referred to as an enhanced warp drive. With the enhanced warp drive, the Equinox successfully traveled over ten thousand light years in less than two weeks. The energy extracted from the corpse of a single nucleogenic lifeform was only useful in increasing the ship's warp factor by 0.03 percent for a single month. The crew began to systematically murder more lifeforms and perform the procedure repeatedly, presenting them with the possibility of returning to the Alpha Quadrant in mere months. (VOY: "Equinox, Part II")