[hayden55]

If you guys watch engineering explained videos he has a good contact with mazda. Hes commented multiple times saying the engine will have a peak efficiency of 43% vs the current engine at around 35%, but average thermal efficiency should be way up. And as all of us racing types know its avhp and avtq over the operating range that wins, not peak horsepower with no meat. Should be interesting. I forsee a couple numbers up on the highway but a nice jump in the city mileage. They also noted that it may not sound like a huge change but when you actually hit the gas it should have a huge advantage in efficiency over your typical prius which has a low of 2% thermal efficiency.
Next gen engine after the X is rumored to hit 56% from Mazdas very optimistic mouth so fingers crossed. This is more beneficial to saving energy than electrification if more manufacuters can get their lineups to start utilizing 50%+ efficient engines.