What is a recommended sedan car cruise speed to achieve the best performance in terms of gas consumption?”
I have been experimenting with this a few months. I found car manufactures like 70 mph, because it uses fuel, so do the gasoline companies. I work for a large oil company and they do not tell us this but tell my congressman to back the higher speed limits. This tells me the higher limits uses more gas. I have a large auto and it gets 4 miles to the gallon better at 65 than it does at 70. I have a full size truck also and the same results. For the extra 10 to 15 minutes it causes in travel I save large amounts of fuel cost be just slowing 5 mph. I would support a 5 mph reduction in speed to conserve fuel today easily. The last few months and the Green Channel on TV have shown me conservation can be achieved without any sacrifice in comfort, in fact it can be a lot of fun getting there.
The real question is what variables can you control to improve mileage: Tire Pressure – did you get your gauge from McCain? It can really make a huge difference in mileage if you have under-inflated tires. Running them up toward the high end of the recommended pressure is your best bet. Wind resistance – here, you bought the farm if your car is not aerodynamic. No plastic foil on the hood will deflect the wind enough to cut drag. What does save though is cutting the wind – following a truck from a safe distance, or even an SUV can improve mileage. I have seen a 5% improvement as measured by the instantaneous mileage gauge on my dash. If the truck is going faster than 60, then your most economical speed is his speed. Slope: Downhill, you can go faster because you are using gravity, not gas, to gain speed. Uphill, don’t accelerate. Let yourself loose a little speed, without going too much slower than traffic. Make it seem like you are being polite by following the truck uphill, letting o
The smart answer is zero. But that defeats the purpose of having a car. The best mileage is usually at the engine’s torque peak. That information might be available somewhere in the car’s tech info. Plan B is to install a vacuum gauge and look for the maximum vacuum at cruise speeds. Plan c is to buy a fuel mileage meter. It won’t be accurate but it will tell you relatively the fuel mileage. There are a lot of ifs an buts. If there were an easy answer, the car manufacturers would tell you.
