What do you mean, works harder? it is doing the same amount of work. According to JTK under his usage it was a 1mpg difference--small but there. Less fuel burn = ... well it's the same amount of work done, but arguably the V6 has less internal resistance so it was working less hard. Under load, things do change. At any given load the V6 is using a larger percentage of its available power, sure. Is that what you are referring to? It's been a while but I recall the TFL guys taking two RAM's up Ike under the same load yet getting basically the same mpg--one was a Hemi and the other a Pentastar. Arguably an engine used at a higher percentage of its available power output should wear out faster. But how many of us have really worn out an engine under our right foot?
Originally Posted by alarmguy
The smaller engine has to work harder.