An optimally-designed commercial engine will probably NOT have its lowest Specific Fuel Consumption at TO, but instead somewhere down the power curve (an SFC "bucket", if you will.) Thus most of the trip fuel gets burned in the region of greatest engine efficiency.
Additionally, the "overpowered" twin will get to cruise altitude quicker, and thus (additionally) have fewer traffic conficts during climb.
Given these real-world issues, I'm not surprised the LR twin can beat a quad.
Last edited by barit1; 15th Nov 2006 at 00:13.
Reason: clarification