Fuel mileage

 

On the way up to Colorado from Texas we drove in 5^th gear a lot because we had that shudder in 6^th gear.  I got to wondering how much that was costing us in fuel; driving at higher rpm in 5^th gear.

 

With our monitoring system, we can track multiple trips, so I set up two different trips, one for 5^th gear and one for 6^th gear.  I tracked these trips while we were driving on wide open fairly level roads.  I set cruise control on 65 and alternated the trip tracking, 10 minutes in 5^th gear, 10 minutes in 6^th, then back to 5^thand so on.  I alternated to eliminate the variable of terrain as much as possible.

 

The result?  How much was it costing us in fuel economy to drive in 5^th gear instead of 6^th?  A counterintuitive result.  We got a full mile-per-gallon better in 5^th gear than we did in 6^th!