Fuel economy and additives
I drive a Forest River Georgetown w 4 slides an a V10 Triton gs engine. Typically i drive 62-65 mph on the hwy. I will be doing a gas log of my fuel economy, but I think it is 7.5 mpg fully loaded. I...
Forum Discussion
1320Fastback wrote:
Also your best miles per gallon should be in the highest gear possible at peak torque.
Not really; peak torque is probably where the engine is most efficient, but that does not mean it's the most efficient speed for the vehicle as a whole. Usually the most efficient speed would be about as slow as you can go while still staying in the top gear and not lugging the engine too much.
Air resistance, a major contributor to the frictional losses of a vehicle (and especially so for one as aerodynamic as a barn or brick), increases with something between the cube and the fourth power of speed. A relatively small increase in speed requires considerably more power, and hence a greater rate of fuel consumption.
I haven't done much study with my motorhome, but I can definitely say that with my car 45 mph or so is noticeably more fuel efficient than 65 mph, while the peak torque in the top gear would be at some speed above 75+ mph. (I don't know precisely what its torque curve looks like.)
