Attention: TDR Forum Junkies 
Fuel Economy in order of importance
Truck Spec for a given year of production:
Worst:
4WD, Auto, DRW
Best:
2WD, Manual, SRW
2). Climate:
Southern US beats all else.
3) Topography
Prairie best.
Mountains worst
4). Driver motivation
Few are motivated. And I mean one in 100,000.
Most want some magic device so as to continue
ignoring childish habits. It’s all about feelz.
Kenworth found where all else was absolutely identical the difference between best and worst drivers was .33
The “problem” with highway driving is also feelz
- spending more on fuel in a shorter timeframe
- really poor discipline.
The old rules are two:
- Don’t exceed 80% engine load
- Best results are
600F EGT
6-psi
60-mph
60-mph is the aerodynamic wall. Exceed that and FE drops like a stone.
62-64 returns best results while keeping with traffic flow. Cruise control ON 100%. All stops planned in advance (2-hr max apart).
Those who wish to understand will use Engine Hours against Odometer to get AVERAGE MPH.
That average is tracked against AVERAGE MPG. An annual figure. Keep records, or go home. FUELLY phone app, for instance.
Increases in the average MPH on a trip burn a helluva lot more fuel than cut travel time. Really, on trips under 300-miles, there is no time savings worthy of note. (If you want to argue, produce first the numbers. Not feelz).
Besides, on the Super Slab is the need for vehicle spacing. 300’ is a minimum. No one gets to travel a perfect set speed.
That spacing and it’s maintenance (managing overtaking traffic by cancelling cruise and sliding under 60-mph) results in you and the truck just gliding along. All day.
Ever hear the phrase, Can’t fix stupid? That’s anyone who allows vehicles ahead, behind and next to them. Ever.
The left lane is ONLY for a short hard pass. Never a travel lane (that’s the design criterion: keep the right lane moving). Left lane has no ROW. Cannot ever block access to left lane. Etc.
Safety & FE track each other most of the way.
And, there no such thing as a pickup that is safe above 65-mph. (Already a stretch, as 55 is where it’s ready to roll over. No worse highway vehicle).
Since traffic volume will dictate highest average speed (speed limit is irrelevant), travel in lowest volume works. That’s daily from 2300-1100 nationwide.
Plan to cross major metros at best hours. They “start” a minimum of 75-miles from city center (the distance most regional delivery takes place for a round trip; plus commuters).
Those two factors can argue for a pretty far detour in terms of miles. Works for me all the time (I drive over 100k per year).
FE will always be steady-state. Cruise control. No lane changes. Brakes used only once on exiting road. Zero idle time. Etc.
And, no magic device will increase steady-state mpg. Call and ask the manufacturer. I did. (Other benefits may apply).
If you want to spend money to save money:
1). Highway Rib, closed shoulder tires at proper inflation (and new shocks). Nothing else will do more.
2). Zero steering slop. Nothing less than this is acceptable.
3). Perfect alignment
4). Zero brake drag
5). Posture, glass and mirrors all ideal. Prescription sunglasses. Water & snacks at hand. Meals planned.
A diesel truck is expensive to own and operate. Get a plan. Learn discipline.
My 13L 21,500-lb Peterbilt will hit 14-mpg at 67-mph with no adverse winds while bobtail. Think about that. 12-mpg long distance is a norm.
. And 10-mpg isn’t unusual with as much as a 60k gross. Usually in the 8’s as most routes have hilly terrain.
My pickup hasn’t ever seen less than a 24-mpg Highway average solo. Towing my 35’ travel trailer it’s 15-mpg. 19-city.
I spec’d The highest MPG truck and have a fully (true) aero TT. I knew what I was doing before I bought either. And I live in the South Central US. And have a plan.
So the numbers aren’t just the magic of spec and locale. It’s driver motivation.
Don’t assume mech spec is okay on your truck. VERIFY. Besides bad tire choices and not knowing how to drive (you don’t), it’s too much slop in the truck. Body bushings, steering, etc. It all adds up.
Good luck
.
Truck Spec for a given year of production:
Worst:
4WD, Auto, DRW
Best:
2WD, Manual, SRW
2). Climate:
Southern US beats all else.
3) Topography
Prairie best.
Mountains worst
4). Driver motivation
Few are motivated. And I mean one in 100,000.
Most want some magic device so as to continue
ignoring childish habits. It’s all about feelz.
Kenworth found where all else was absolutely identical the difference between best and worst drivers was .33
The “problem” with highway driving is also feelz
- spending more on fuel in a shorter timeframe
- really poor discipline.
The old rules are two:
- Don’t exceed 80% engine load
- Best results are
600F EGT
6-psi
60-mph
60-mph is the aerodynamic wall. Exceed that and FE drops like a stone.
62-64 returns best results while keeping with traffic flow. Cruise control ON 100%. All stops planned in advance (2-hr max apart).
Those who wish to understand will use Engine Hours against Odometer to get AVERAGE MPH.
That average is tracked against AVERAGE MPG. An annual figure. Keep records, or go home. FUELLY phone app, for instance.
Increases in the average MPH on a trip burn a helluva lot more fuel than cut travel time. Really, on trips under 300-miles, there is no time savings worthy of note. (If you want to argue, produce first the numbers. Not feelz).
Besides, on the Super Slab is the need for vehicle spacing. 300’ is a minimum. No one gets to travel a perfect set speed.
That spacing and it’s maintenance (managing overtaking traffic by cancelling cruise and sliding under 60-mph) results in you and the truck just gliding along. All day.
Ever hear the phrase, Can’t fix stupid? That’s anyone who allows vehicles ahead, behind and next to them. Ever.
The left lane is ONLY for a short hard pass. Never a travel lane (that’s the design criterion: keep the right lane moving). Left lane has no ROW. Cannot ever block access to left lane. Etc.
Safety & FE track each other most of the way.
And, there no such thing as a pickup that is safe above 65-mph. (Already a stretch, as 55 is where it’s ready to roll over. No worse highway vehicle).
Since traffic volume will dictate highest average speed (speed limit is irrelevant), travel in lowest volume works. That’s daily from 2300-1100 nationwide.
Plan to cross major metros at best hours. They “start” a minimum of 75-miles from city center (the distance most regional delivery takes place for a round trip; plus commuters).
Those two factors can argue for a pretty far detour in terms of miles. Works for me all the time (I drive over 100k per year).
FE will always be steady-state. Cruise control. No lane changes. Brakes used only once on exiting road. Zero idle time. Etc.
And, no magic device will increase steady-state mpg. Call and ask the manufacturer. I did. (Other benefits may apply).
If you want to spend money to save money:
1). Highway Rib, closed shoulder tires at proper inflation (and new shocks). Nothing else will do more.
2). Zero steering slop. Nothing less than this is acceptable.
3). Perfect alignment
4). Zero brake drag
5). Posture, glass and mirrors all ideal. Prescription sunglasses. Water & snacks at hand. Meals planned.
A diesel truck is expensive to own and operate. Get a plan. Learn discipline.
My 13L 21,500-lb Peterbilt will hit 14-mpg at 67-mph with no adverse winds while bobtail. Think about that. 12-mpg long distance is a norm.
. And 10-mpg isn’t unusual with as much as a 60k gross. Usually in the 8’s as most routes have hilly terrain.
My pickup hasn’t ever seen less than a 24-mpg Highway average solo. Towing my 35’ travel trailer it’s 15-mpg. 19-city.
I spec’d The highest MPG truck and have a fully (true) aero TT. I knew what I was doing before I bought either. And I live in the South Central US. And have a plan.
So the numbers aren’t just the magic of spec and locale. It’s driver motivation.
Don’t assume mech spec is okay on your truck. VERIFY. Besides bad tire choices and not knowing how to drive (you don’t), it’s too much slop in the truck. Body bushings, steering, etc. It all adds up.
Good luck
.
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