F150 2.7 EB vs 5L V8 towing mpg

If at elevation, the eco boost may have been making more power. It very well could have held speed better.

APT wrote:
Was average speed higher for 2.7L? I expect the Ecoboost maintained speed better in combination with what @ShinerBock listed for effective displacement/fuel

Not likely or perhaps even possible with less power by such a margin.

Lots of missing details, otherwise the MPGs are out of context

Gassers are designed for stoichiometric ratio during open loop and when up to temp, closed loop can vary +/- depending on both temp and whether oxygenators are in the fuel

What is the elevation ?

What is the boost ?

What is the throttle position ?

What are the gear ratios from the tranny to the diff and to pavement vs ICE RPMs at the pavement

Stuff like that is missing...else comparing apples to oranges...IMHO

Was average speed higher for 2.7L? I expect the Ecoboost maintained speed better in combination with what @ShinerBock listed for effective displacement/fuel

Can you provide a link to the test data?

Doesn't surprise me. The 2.7L Ecoboost has a greater effective displacement at full boost(moving as much air as a 5.9L) and is able to move more air at altitude than the 5.0L. The more air you add the more gas you need to keep it around a 14.7:1 air/fuel ratio which lowers fuel economy but increases performance.