Thermodynamics hasn’t changed in 30 years.
People think because of all the advances in computers abd technology, other fields can advance at similar rates. It isn’t so.
If half of our passenger car fleet were diesel powered today, we could slash oil imports by about 30%. We begged George Bush to executive-order boutique diesel fuels out of existence, and it wouldn't hurt to stop the insane gasoline blending mandates that differ wildly from metro area to metro area, either.
What about shoving more air into the intake? Find away to moderate fuel with air intake for max performance. They have this already, but I think it could be made to perform more efficient. Also, like Kenny Bunk says, get rid of the different blends. We should make one outstanding blend that gives you the power you need. The higher octane I ran in my Formula the better the car ran. I ran racing fuel in it a few times and it ran good. I can't tell you the gas mileage, but I can tell you that it ran good.
Hey, I may be wrong. Maybe this is as good as it gets, but I honestly think we could do better.