In 2266, the normal intermix formula used on the warp drive of Constitution-class starships required thirty minutes, or twenty two if hastened, to regenerate the core when it was initialized from a shut down state. The USS Enterprise became the first starship to test a theoretical new formula based on the relationship between time and antimatter. It involved a complete cold start of the core, without regeneration or heating of the antimatter. The crew were forced to use this theoretical formula when they attempted to avoid a crash landing to the Psi 2000 planet.
The formula worked, and the ship did not explode, even though there was only a ten thousand to one chance of success. It also had the side effect of generating more engine power than was possible to read with the ships instrumentation, and a warp speed greater than was theoretically possible to achieve in normal space. The ship escaped this time warp by simply reversing power. (TOS: "The Naked Time")