I can't say as I am expert...but have had 4,6,8 cyls, gas and diesel, and can drive a tractor trailer...I started here with mechanical injection, 350 cummins, 425, 475, 500, 550...
I learned something about fuel, someone tell me if I am wrong.
As standards go, as oe, body to engine power and weight are all similar, unless the engine is famous..(like a 3 main boxer in a 3000 pound vehicle)..
even if the engine is unique in less friction, greater casual balance.. something stays the same for 87 octane...asone climbs though tunes and performance and gears..attempoting to maximize potential for the given drivetrain and body.
on a recent trip, I am proud of for speeeding (it is very rare mind you)
I could not wait to decipher 92mph for approx 80 miles-100 miles... and realized...it was 27mpg.
Now I do have alot of tinkering the past 20 years..and realized my v8 monte carlo with 2.73 rears and a 200r4 tranny...did very very similar, I mean within a mile a gallon... 90mph...25-27 mpg...
it occured to me... if near oe specs for power to weight, and tuned by backyarders like me... all cars will do the same thing with 87 octane, unless the engine is famous for being bad,(like inline fours....)
anyone else notice?
even the tractor trailers I evolved with on behalf of my dad... all the same. 5-6mpg...40tons...designed around power to weight by oe..it shows even diesel does it.
I am reminded once and awhile via vids on you tube explaining tunes etc...