3.58 rear, 7.2 to 7.8mpg. Lower RPM is part of the fuel economy equation, but more important is how hard the motor has to work. You can leave it in high gear with your foot in the middle of the turbo and climb a hill at 50mph and 1100rpm, or you can downshift, climb at 1400rpm/45mph and half throttle. You will get better fuel economy with the lower speed/higher RPM because the engine isn't working as hard. If you have a turbo pressure gauge, watch what it's doing. The lower you are able to keep that number, the better your economy will be. This flies directly in the face of most mega-fleet pencil pushers. Their claim is lower RPM, better fuel economy. That only works on flat land and low, gentle rolling hills. It does not work in the mountains. BW9's engine is able to get good economy because he has it tuned to not have to work hard under most circumstances. And he knows how to drive it.