Driving a 2.4 iVTEC Honda Accord with a 65 ltr fuel tank. I always fill with super. Best tank I've had was 90% motorway driving cruise control at 70mph or there about. Refilled after about 430 miles, probably could have gone to 450 though. The paperwork for the car says the best possible tank I could expect to get is just over 400, so I was very chuffed with that indeed. Although, we all know that manufacturers (at least Japanese manufactures) tend to be conservative with their paper based claims.
For sure, high speed cruising, big engines are better. I'll sit at 70mph at little above 2000rpm in a car that redlines at 7000rpm. Whereas if I was driving a little poky car I might be high up the revs to get 70mph. Meaning I'd be burning more fuel.
Some big cars are marketed as
great motorway cars. Mine is one of these for sure, the diesel version even more so. I believe you'll get well over 600 miles from a tank with the Diesel Accord. That's their newer DTEC range by the way. With the 7th generation of accord, Honda ventured into making their own Diesel engines for the first time instead of fitting Isuzu Diesel engines. They could be a diesel to watch I reckon. But enough about Diesel.
100% round town driving, my worst tank, I got 270 miles before the fuel light came on. I reckon if I ragged it and really enjoyed it's potential, I could get as little 200 before needing a refill
. But that's never gonna happen really.