A C&D mag not long ago showed cars/trucks from 20 years ago compared to now. Time and time again, HP/TQ we vastly increased, and MPG was flat-lined.
Diesels pre-2006 we mostly true diesels and could deliver good power with good fuel economy. Today they deal with tough emission standards and have a scary and costly array of components to scrub and chemically clean what comes out the tail pipe. It's insane, and it doesn't result in loss of power exactly, it results in less fuel economy. They might beat gassers still, but the gap has closed drastically as I'm seeing real world towing reports that average only 10% better than gas, if that. Then enter the debate of cost to own.
Regarding MPG of various HP motors...first of all no one is using all available power unless they are WOT. Which SO many people are afraid to do, for fear they are hurting their motor. I am not afraid of WOT.
For more than 2 seasons each, I towed the very same aero shape TT weighing 4300lbs loaded, with a Honda Pilot and Toyota Sequoia.
The Pilot has a 3.5L V6 and the Sequoia a 5.7L V8. Roughly 250hp (Gen2 Pilot) vs 380hp.
They both returned the VERY SAME MPG AVERAGE while towing.
Not towing, I would commonly see 20-22mpg. The Sequoia I commonly see 15-16mpg.
