This would be a turbo that used up half as much energy, and made your ship go the speed between its max speed and max turbo speed (e.g. (65+220)/2=143 for most ships). Also, turning, and strafing movements would be cut in half, instead of disabled entirely like in normal boosting.

The reason for this is that regular boosting is a very large change from going slow to fast, and its hard to use in a fight since you lose control. Also, its sometimes hard to cross an entire sector if you're using a heavy battery, or not in a ship with infiniboost.

Gradient throttles of turbo was suggested in a dev. topic requesting comments. (please search for it)