Originally Posted by 98CoupeV6
I get my best MPG cruising 75-80. I usually get between 28 and 30. Below that or above that I tend to get 26-27. This confuses me as well.
One trip from NYC to Syracuse I got 30.5 MPG doing between 75-90 the whole way behind fast traffic and I hit 135 on an empty downhill stretch...that was weird
I've noticed the same thing. I used to go a consistent 75 on the highway and once managed 36.8mpg round-trip with some use of the AC and a couple patches of traffic. Now I keep it below 70
trying to save fuel but now I'm between 35-36mpg highway. It's strange because drag forces go up with the square of your velocity.
One explanation I've heard is that engines make power more efficiently as RPMs increase (up to a point). So it takes more energy to move the car at 75 than 65 but the engine makes up for it by getting more energy out of each ml of fuel injected. I couldn't even begin to explain why that happens but I can't think of any other way that mileage would improve as velocity increases. Maybe it's as simple as VTEC crossover changing valve lift which would reduce pumping losses? Maybe I should get one of those embarrassing ricer VTEC lights and test it out.