Last summer on a drive to Toronto we did it on 40 liters, the RSX-s tank is 50 liters, (40 liter = 10.566 gallons) from our house to our final destination 326 miles...30.85 mpg that's with the car full of stuff for a long weekend and the dog's cage and the dog, she weighs about 90#. On the expressways I drove about 80-85 mph.