[Big Dave]

Turbos have little effect on diesels because diesels operate at an "excess air" condition. The combustion event occurs on the surface of the fuel droplets where in a gas engine the fuel/air mixture is (more or less) uniform through the whole combustion chamber.

Otto-cyle engines are married to an air:fuel ratio. Stuff more air in and you have to add more fuel. If you don't have enough load, you'll have to throttle down and that reduces thermodynamic efficiency.

This is why direct-injection is exciting. It generates a local sufficient mixture in the combustion chamber without the thermal losses of a pre-combustion chamber. The "rich" area around the centerline of the injection pattern "blowtorches" the leaner outlying areas into combustion.

Unless you have direct injection or a pre-combustion chamber (Honda CVCC) increased vol eff means increased fuel flow.