Poor gas mileage

[Mountain Whiskey]

Not sure it is the etouque as much as just plain wind resistance. I usually stay around 14.3 to 14.5 mpg. This is because 40 miles of my 50 mile (one way) commute is highway. I drive a bit fast and heavy footed on the highway.

When the wife and I went out for a weekend and drove some country roads to go out to the butcher shop, it jumped an easy 2mpg. That was just easy driving from 35 to 55 mph. The truck was not pushing against the wind the whole time. It's just easier driving around town and on the back roads rather than the bloodbath on the highway.

 

[theblet]

I just went from 18.3 to 16.1 while waiting two hours to see a doctor they said I could wait in my truck, so watched some tv on the laptop.

 

[AngelPhoenix]

I finally got up over 17.5...

For like 2 minutes, at 17.2 right now. Was hoping for at least 18 and I think I can get there, just have to take it a little easier on the curvy highways and never ever ever ever idle.

 

[JF19Longhorn]

Holy Headwind!

Trip Friday from South Jersey to BFE PA to visit the inlaws.. zero traffic, but a bad headwind the entire way. Truck actually had to downshift acouple times to maintain speed. ..still on the return trip tank, but there was no wind otw home and it's looking to be in the normal crap mileage this truck gets on the Hwy.. (mid 16mpg)

 

[asgadf/lkjnadsfg]

^^^So if you speak with a British accent, you can immediately get 17.3 MPG? Am I reading that right? Not a bad tradeoff, especially since you don't have to do it all the time, just while you're in the truck.

That's the first time I've ever seen "UK MPG".

 

[MurphBigHorn]

I just went from 18.3 to 16.1 while waiting two hours to see a doctor they said I could wait in my truck, so watched some tv on the laptop.

Better set up that warranty for cracked manifolds. With all that’s idling.

 

[SpeedyV]

Holy Headwind!

Trip Friday from South Jersey to BFE PA to visit the inlaws.. zero traffic, but a bad headwind the entire way. Truck actually had to downshift acouple times to maintain speed. ..still on the return trip tank, but there was no wind otw home and it's looking to be in the normal crap mileage this truck gets on the Hwy.. (mid 16mpg)

View attachment 112452

That's a 3.92 for you

I just wrapped up a 3,300 mile road trip. I have a heavy truck (1,069 payload). I ran on the OEM Falkens, but I did not add pressure. The door sticker says 32 psi, and I typically run closer to 38 psi.

On the outbound leg, I was towing a dual-axle U-Haul trailer carrying furniture with additional gear in the bed, plus my wife and I, two dogs, and luggage in the cabin (near max payload). On the return leg, I ditched the trailer but had a portable generator and other gear loaded in the bed, so I was still near max payload.

Here were my hand-calculated results (tracked with Fuelly):

Towing at or near max payload:
9.5 mpg (91 octane)
9.5 mpg (90 octane ethanol free)
11.4 mpg (91 octane)
10.1 mpg (93 octane)
10.1 mpg (93 octane)
12.9 mpg (93 octane, partial towing)

Not towing but near max payload:
15.6 mpg (93 octane)
15.8 mpg (93 octane)
15.4 mpg (91 octane)
15.1 mpg (91 octane)

I wouldn't read into the octane ratings too much here, as there were lots of variables (hilly sections, wind in all directions, varying speed limits, construction zones, etc.). Honestly, and unsurprisingly, speed was the biggest factor; economy was significantly higher when rolling through construction zones at 50-60 mph and dropped like a rock on open roads with 75-80 mph speed limits.

 

[theblet]

Better set up that warranty for cracked manifolds. With all that’s idling.

I thought the same thing. Was trying to keep my sick kids happy and that’s the only way to keep the inverter running

 

[Mountain Whiskey]

I thought the same thing. Was trying to keep my sick kids happy and that’s the only way to keep the inverter running

Sick?!? What were they doing in the cab then. They can ride in the bed and not spread a bunch of contagion your way!

 

[Mountain Whiskey]

Holy Headwind!

Trip Friday from South Jersey to BFE PA to visit the inlaws.. zero traffic, but a bad headwind the entire way. Truck actually had to downshift acouple times to maintain speed. ..still on the return trip tank, but there was no wind otw home and it's looking to be in the normal crap mileage this truck gets on the Hwy.. (mid 16mpg)

View attachment 112452

Aside from from the Brits not knowing how much a gallon is, , I want to know where you get the electric gas this truck needs to run. We just have unleaded around here!

 

[theblet]

Sick?!? What were they doing in the cab then. They can ride in the bed and not spread a bunch of contagion your way!

Lol. There’s a virus going around (not Covid) and I’m the only one that isn’t sick. Guess my vitamins or the beer kept me good.

 

[JF19Longhorn]

Aside from from the Brits not knowing how much a gallon is, , I want to know where you get the electric gas this truck needs to run. We just have unleaded around here!

It's a special blend made from ferry dust and unicorn ****.

 

[AngelPhoenix]

That's a 3.92 for you

I just wrapped up a 3,300 mile road trip. I have a heavy truck (1,069 payload). I ran on the OEM Falkens, but I did not add pressure. The door sticker says 32 psi, and I typically run closer to 38 psi.

On the outbound leg, I was towing a dual-axle U-Haul trailer carrying furniture with additional gear in the bed, plus my wife and I, two dogs, and luggage in the cabin (near max payload). On the return leg, I ditched the trailer but had a portable generator and other gear loaded in the bed, so I was still near max payload.

Here were my hand-calculated results (tracked with Fuelly):

Towing at or near max payload:
9.5 mpg (91 octane)
9.5 mpg (90 octane ethanol free)
11.4 mpg (91 octane)
10.1 mpg (93 octane)
10.1 mpg (93 octane)
12.9 mpg (93 octane, partial towing)

Not towing but near max payload:
15.6 mpg (93 octane)
15.8 mpg (93 octane)
15.4 mpg (91 octane)
15.1 mpg (91 octane)

I wouldn't read into the octane ratings too much here, as there were lots of variables (hilly sections, wind in all directions, varying speed limits, construction zones, etc.). Honestly, and unsurprisingly, speed was the biggest factor; economy was significantly higher when rolling through construction zones at 50-60 mph and dropped like a rock on open roads with 75-80 mph speed limits.

This is good info Speedy, thank you!

I'm starting to get the hang of how not to let her eat up so much fuel. It's definitely a different sort of driving style from everything I've had before. Basically I go a bit slower on average and open her up only about half as much as I'd really like to, but when I give her the gas MAN does she go!

 

[SpeedyV]

This is good info Speedy, thank you!

I'm starting to get the hang of how not to let her eat up so much fuel. It's definitely a different sort of driving style from everything I've had before. Basically I go a bit slower on average and open her up only about half as much as I'd really like to, but when I give her the gas MAN does she go!

I wouldn't worry about it too much, as even a 10% improvement is a difference of <2 mpg.

That said, I wish I'd put 40+ psi in the tires prior to towing. Having just inflated them to 38 psi cold (40-42 warm), I can actually feel the difference in rolling resistance.

 

[AngelPhoenix]

I wouldn't worry about it too much, as even a 10% improvement is a difference of <2 mpg.

That said, I wish I'd put 40+ psi in the tires prior to towing. Having just inflated them to 38 psi cold (40-42 warm), I can actually feel the difference in rolling resistance.

That's sounds about right. Driving it like I did my Grand Cherokee (and Cherokee before that), I was averaging between 15.4 and 15.8. Driving like I do now, I'm up over 18 (my average is like 17.8 now after just a couple more days of driving differently, and climbing). My wallet feels that, especially when pumping 89 at these prices, that will add up over the whole stretch of owning the truck.

And since you mentioned about pumping up the tires for towing, I would think higher is always better but what would you say is the cutoff for 50 max PSI tires? I imagine that lugging around an extra 6K+ lbs of travel trailer, especially in warmer weather, will heat the tires up pretty good. So if you go all the way up to say like 47, 48, you'd be putting yourself in blowout territory no? Would like 42-44 be safe?

 

[IvoryHemi]

That's sounds about right. Driving it like I did my Grand Cherokee (and Cherokee before that), I was averaging between 15.4 and 15.8. Driving like I do now, I'm up over 18 (my average is like 17.8 now after just a couple more days of driving differently, and climbing). My wallet feels that, especially when pumping 89 at these prices, that will add up over the whole stretch of owning the truck.

And since you mentioned about pumping up the tires for towing, I would think higher is always better but what would you say is the cutoff for 50 max PSI tires? I imagine that lugging around an extra 6K+ lbs of travel trailer, especially in warmer weather, will heat the tires up pretty good. So if you go all the way up to say like 47, 48, you'd be putting yourself in blowout territory no? Would like 42-44 be safe?

50 psi cold max means just that, 50 psi *cold*

Sure the tires will heat up over the cold max pressure but your still within the designed tolerances which doesn’t put you in blowout territory.

 

[AngelPhoenix]

50 psi cold max means just that, 50 psi *cold*

Sure the tires will heat up over the cold max pressure but your still within the designed tolerances which doesn’t put you in blowout territory.

It's kind of ridiculous how much I've learned on this forum from ya'll. Thanks Ram Tow Guru!

 

[SpeedyV]

That's sounds about right. Driving it like I did my Grand Cherokee (and Cherokee before that), I was averaging between 15.4 and 15.8. Driving like I do now, I'm up over 18 (my average is like 17.8 now after just a couple more days of driving differently, and climbing). My wallet feels that, especially when pumping 89 at these prices, that will add up over the whole stretch of owning the truck.

My truck won't ever see those numbers here in Texas, where I'm either in city traffic or running 75 mph on the highway. If I drive like a grandpa (and I often do), it makes zero difference. It's just the reality of a heavy truck with 3.92 gearing in this scenario. My 14+ mpg lifetime average beats the 11 mpg my previous truck averaged in the same conditions.

Now up at the lake (Michigan), where I'm rolling on state highways for long stretches at 60 mph, it's a VERY different story. 15-17 mpg is easily achieved.

 

[AngelPhoenix]

My truck won't ever see those numbers here in Texas, where I'm either in city traffic or running 75 mph on the highway. If I drive like a grandpa (and I often do), it makes zero difference. It's just the reality of a heavy truck with 3.92 gearing in this scenario. My 14+ mpg lifetime average beats the 11 mpg my previous truck averaged in the same conditions.

Now up at the lake (Michigan), where I'm rolling on state highways for long stretches at 60 mph, it's a VERY different story. 15-17 mpg is easily achieved.

Need that high-quality blinker fluid.

 

[ABess]

My truck won't ever see those numbers here in Texas, where I'm either in city traffic or running 75 mph on the highway. If I drive like a grandpa (and I often do), it makes zero difference. It's just the reality of a heavy truck with 3.92 gearing in this scenario. My 14+ mpg lifetime average beats the 11 mpg my previous truck averaged in the same conditions.

Now up at the lake (Michigan), where I'm rolling on state highways for long stretches at 60 mph, it's a VERY different story. 15-17 mpg is easily achieved.

Yeah, Houston traffic doesn't play well with MPGs. Its all good. Everytime I jump in the truck I smile, and everytime I jump out of it, I count to 4 thousand like a good paratrooper!