Quote:
Originally Posted by lovemysan
I can tell you that unloaded the car has a modest amount of usable accel from 50mph in 5th. On ramps are FE killers. Loaded full of family you pretty much set the throttle to 20% and wait for accelleration to occur.
From a strictly efficiency perspective the engine is most eff at 2500rpms. My understanding(small brain here) is at max efficiency its producing the best ratio of BTU's used vs work produced. Unfortunately at 73mph a lot of work is wasted on aerodynamic load.
I believe the best FE is attained around 39-42mph for the MP2 equipped saturn. I have one tank at 62mpg, where at didn't really exceed 50 mph.
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Yeah, you're right in general about slower being more efficient, but I was talking about driving in top gear at a useful speed. At 39-42mph I would think 5th gear would be useless.
It's always a compromise. Could we get better hwy mileage with P&G at a very slow speed? Yep. But most of us will probably sit and drive at a tolerable highway speed, loading it more on the uphills and coasting down the back side when convenient.
Realistically, I probably wouldn't drive slower than 50mph for any amount of time on the highway, and with the right gearing, wouldn't feel too badly about doing 60.
-Chris