Lasted edited by Andrew Munsey, updated on June 15, 2016 at 1:30 am.
'''Higher speed, lower millage? - not so
I will disagree with the statement that higher speed reduce fuel consumption.
From basic physic law you can see that higher speed increase air drag (specially between 50-70miles).
The numbers presented above look very suspicions. I am not saying that they are wrong for the car that the author used.
I suspect two things:
1. Something wrong (technically) with the author car.
2. Or, the car design is not optimized for efficiency.
I will not be surprise that same model of Nissan produced for European market have much better millage. In 2000 in US no body did care about millage, however acceleration from the marketing point of view was very important.
In most cases the car transmission is optimize to operate with best efficiency with optimum engine speed. If the manufacture of the car like better acceleration, then the final ratio (usually in differential) will be to set to lower speed higher torque.
If the efficiency is the goal the approach will be reverse.
The latest approach is just use CVT (continuously variable transmission) or transmission with 5-6 or more gear, so best option can be choose (economy or performance)
With automatic transmission it is difficult to experiment, however with manual transmission it can be done.
If you will switch to higher gear ration at lover engine speed you should get better millage.
The penalty is acceleration.
The author is right about the city driving, or better not driving during idle cycle.
Driving 11 miles in 2.5 hours (most of the time staying in traffic) will not give you good millage even with the best conventional car. Hybrid cars are much better in that regards.