Well, my 2018 SVTC used to get about 42 highway (65-70mph), but I’ve been exclusively in Sport Mode and running a bit faster at 75-80mph. At those speeds I’m seeing about 37-38mpg. That’s not bad for 1900cc.
Now that I have Ivan’s tune in my ECM, I’ve been told I should see high 40’s at 65-70mph. I did note that when cruising the Blue Ridge at 45mph I was getting 57mpg. On a 6.6gal tank that’s quite a distance.
My crf230l get over 70 average on my ~50 mile round trip commute. But I have my limits. When it's warming up I'm generally on the AT or CBR, but when it's triple digits I'm driving my ~14mpg Yukon! I want my A/C!