Gearloose:

It may sound strange but oddly enough, improving the flow, pressure and subsequently the spray pattern, means a more efficient burn. These engines were designed as a total compromise so any thing you do to improve the burn characteristics can only help to improve the fuel economy.

Moondoggie:

Maybe it would be easier to first convert to liters. Your girlie gallons only contain 3.8 liters while our macho gallons take up 4.546 liters.

Either way the 80% rule is close enough.

Bill