Fuel Saving Tips
If you have an automatic with a manual feature (such as some newer Mazdas, Hondas, and other vehicles may have) then you can micromanage your gears for better fuel efficiency. The most important thing to figure out is at what RPMs the vehicle starts to get more power out of it. I found on my wife's Mazda 3, its at about 2.8k RPMs, which at 60 mph it actually was cruising at 2.25k RPMs in 5th gear, which meant that it was fuel inefficient climbing even slight hills and in a headwind. Switching to 4th gear, even at 60 mph, brought the RPMs to 3k (halfway to redline), and with it the power to fuel efficiently climb even slight hills or to cruise in a headwind. In fact, in my wife's car, with a slight amount of headwind, 4th gear and 5th gear use the same amount of fuel to cruise at 55mph even though 4th gear uses more RPMs. The catch is, with a light load, such as with a tail wind, down hill, or coasting up to a stop, 5th gear is almost always the most fuel efficient gear since it is the most like neutral; even at low speeds like 35 mph. Note that leaving it in drive it'll often stay in 5th gear even when the car seems to just inhale gas before finally getting some power. As it turns out, the most efficient speed for 5th gear on my wife's mazda 3 is a whopping 73-75 mph, more than most speed limits in the area. Also, when using a car with a manual mode, always let it automatically downshift for you when slowing down unless you anticipate accelerating before you come to a stop. It won't hurt anything.
posted by FBX on July 18, 2010
this tip works for 35% of voting Fuelly members.