Quote:
|
Originally Posted by M3Armand
While on the highway, the car downshifts while you are passing. When you get to a toll booth, you do some stop and go's. I was surprised to see how much this mattered. When you go on slight uphills, it also downshifts. When you shift yourself, you have control over whether or not you want to downshift out of 6th gear.
No, technically speed is NOT the biggest factor in determining mpg while "cruising" on a flat highway. It's drag coefficient and weight. It's RPM (i.e. - how fast your engine is spinning, and therefore, consuming gas) and any acceleration. If you keep both on the low end; i.e. - slow acceleration while keeping RPM's low, you would get the best mileage.
|
OK, I thought when you said "highway" you meant relatively flat Intertate w/o significant traffic, and no toll booths etc. that required you to stop.
As to your second point, since the other factors you mention (drag coefficient, weight) are basically fixed, then speed IS the one variable that makes a difference in mileage. (you also mention RPMs, but it should be a given that you're not cruising highway speeds in less than top gear) In fact, aerodynamic drag increases at a rate equal to the square of velocity (i.e. a 20% increase in speed means a 44% increase in drag). So speed is a mileage killer......unless you're on the moon.
