To get more FE...drive faster?

[lovemysan]

I have a relatively small aerodynamic car with a long overdrive. At 70mph its turning just under 2500rpms. Peak torque is 2400rpms. I have found that the slower you go the better mileage you get. In rolling country hills two lane roads I can average about 60mpg. I limit minimum speed to 35mph up hill.

I can get around 50mpg at 60-65mph. I can get 60mpg at 42mph. Last tank was 62mpg scangauge reported 29mph average. Thats the nature of the beast.

I find that on a busy freeway I can ease in with a large group of semis doing a 2.5-3 second draft and get 50 mpg at 68-72mph. I was also able to drive out of KS city last weekend for 200 miles at 70+mph and held 49mpg for over 200 miles no drafting. It was a tailwind.

Conclusion, although driving slow puts the engine well outside its most effiecent range I still net better FE.