On Sun, 09 Dec 2007 17:41:37 GMT, Jere Lull wrote:

In particular, check the difference in fuel usage at the same cruising
speeds, as I've found it's easy to set the same RPMs, benefit from
increased speeds, but suffer from decreased mileage.

Since it inevitably takes more net horsepower to increase speed,
increased fuel usage should be expected. There's no free lunch... :-)