Take the 2-minute tour ×  I'm specifically referring to the loss
due to the pistons pulling air through a mostly closed throttle
while cruising at highway speeds in a gasoline engine.  To give
an example, I've always wondered why this wouldn't be more
economical fuel-wise:  Add another gear to the gearbox, say a
sixth gear to a 5-speed car. This gear would be useless for
accelerating whatsoever; it would be such a high ratio that at
65 MPH, wide-open throttle, it would hold the vehicle at a
steady pace or only slightly accelerate. This would reduce much
of the pumping losses from making the pistons suck through a
nearly closed throttle, and would seemingly allow for better
fuel economy, due in part from both 1) lower RPM so less
friction loss and 2) less pumping loss.  I am aware other things
may need to accompany this; for example WOT in 6th gear should
not richen the mixture as WOT does normally, etc., so let's say
the car was produced from the factory with the computer and
associated electronics accommodat