My brother and I met in Jacksonville once to swap cars. My brother's S13 with tuned SR and 4.3, and my completely stock S13 with fully maintenanced KA. Both cars went 250miles. We both filled up. I got 26mpg, which is what it's rated for. He got a hair over 30mpg.

On that Tennessee trip, I was averaging 25mpg in my full weight plus sub/amp S14, with 245's, 4.3, and stock KA. That's only 1 mpg less than my S13 would do with the same motor, but with a much heavier car, shorter gear, and higher rolling resistance tires.

I like that plot up there, greenman. I knew things like that existed, but never searched them out. Behind all that math, you should probably punch in (4.363-4.083)/4.083. Roughly 7%. Pick a spot on that graph. Now divide tq by 7% and multiply revs by 7%. Ain't exactly a big shift. Especially considering that the 2 islands that make up most of that plot only differ by 10%.