Crummy fuel economy

carringb wrote:
I imagine you must have had some really bad head winds. Or even cross winds. The effective drag from cross winds is almost as bad as head winds!

Yes, that is crummy, and is certainly worse than I AVERAGE with my v10 pulling my monster trailer. But mine has dipped down that far on occasion, when the winds are so strong I can't hold OD.

In this case no wind, level ground and not a lot of weight. Just a very big drag chute I guess.

I imagine you must have had some really bad head winds. Or even cross winds. The effective drag from cross winds is almost as bad as head winds!

Yes, that is crummy, and is certainly worse than I AVERAGE with my v10 pulling my monster trailer. But mine has dipped down that far on occasion, when the winds are so strong I can't hold OD.

Dragged our wee TT (about 5,000 lbs, but full height/width) into a 50 mph headwind across Oklahoma once with our little 2.8 liter Jeep Libby CRD (diesel) and it was all I could do to maintain 50 mph on the flat. But I did get 9 mpg! So, not a GM or Dodge, but also not 6 mpg.

Tvov wrote:

4x4ord wrote:
At 75 mph I would have been pumping diesel but I kinda figured 60 mph was fast enough....The implement I was towing was fitted with 30.5 x 32 combine tires rated for a top speed of 25 mph.

I, as usual, am a little confused. You were towing something at more than twice the speed that its' tires were rated for? Why?

I had to tow the thing 280 miles, 25 miles per hour would have been painfully slow as well as being a nuisance on the highway. The tires were only carrying about 5500 lbs each, so running them a little over the rated speed wasn't a big concern.

4x4ord wrote:
With a 5.9 Cummins....wow you must have had your foot into to it pretty good. Were you able to maintain 60 mph?

No problem maintaining speed..........65mph EGT/1200* 4:10 gearing

Could have gone faster but above 65mph EGTs would climb quickly above 1300*F and fuel was getting sucked up fast enough.
SO to keep EGTS at/below 1200*F and try to save some fuel I kept speed to 65mph max.

4x4ord wrote:

Cummins12V98 wrote:
Towing with 11 RAM Dually combined weight 29k into 40mph head winds at 75mph I was 6mpg.

Did you ever pull your '07 MS with your 2015 Ram? I'm curious as to how much more power it takes to pull a 29000 lb RV vs a 20k lb unit?

I did but not any real distance. The 07 scaled about 19k and 11 truck about 10k. I documented speeds on certain grades. The 15 is about 10 and 16 Rv is 23k. Some grades the 11 performed better like thre the Syskious in northern CA. In eastern wa west bound 90 on Vantage pass the 15 did better. 11 had 3.42 with basically same rpm as the 15 with 4.10 running one gear lower. 11 was 350hp 15 is 385.

4x4ord wrote:
At 75 mph I would have been pumping diesel but I kinda figured 60 mph was fast enough....The implement I was towing was fitted with 30.5 x 32 combine tires rated for a top speed of 25 mph.

I, as usual, am a little confused. You were towing something at more than twice the speed that its' tires were rated for? Why?

You titled your this thread, "Crummy fuel economy."

RV'ing = Crummy fuel economy . That's the way it is.

Cummins12V98 wrote:
Towing with 11 RAM Dually combined weight 29k into 40mph head winds at 75mph I was 6mpg.

Did you ever pull your '07 MS with your 2015 Ram? I'm curious as to how much more power it takes to pull a 29000 lb RV vs a 20k lb unit?

At 75 mph I would have been pumping diesel but I kinda figured 60 mph was fast enough....The implement I was towing was fitted with 30.5 x 32 combine tires rated for a top speed of 25 mph.