Fuel economy bad

[Bob4x4]

The sweet spot will vary with modifications but old man Cummins came up with some excellent nbers years ago-600 degrees for max fuel mileage and 1200 for power

 

[JJPage]

Towing on relatively flat ground (only gaining 1,000 feet in 200 miles and nothing more than 5% for . 75 miles)

AH, I'm believing you obtained this info about the OP's area of travel from some map... when leaving Spokane heading west into the rolling, treeless hills, there is nothing to stop the wind. As you approach to the Columbia River, the hills get longer and higher, nothing relatively flat about it. Ryegrass/Vantage may only be 5% for the last mile, but it is 10 miles long travelling west, and the wind currents coming off the river can create a challenge to say the least.

When I was still driving, I used to meet the other driver from Kent at Vantage to swap doubles, the wind would be blowing so damn hard it could rip the driver's door out of your grasp trying to get in or out of the rig. Lost my hat one night, really had to hang on to bill of ladings or they would disappear. I understand the OP did not realize any wind that particular day, doesn't mean it wasn't a factor.

Ryegrass has been the subject of discussion on this forum in the past, it really is shrugged off as insignificant, but I have seen many vehicles off on the shoulder with either steam or fluids running out of them.

 

[cerberusiam]

As you approach to the Columbia River, the hills get longer and higher, nothing relatively flat about it. Ryegrass/Vantage may only be 5% for the last mile, but it is 10 miles long travelling west, and the wind currents coming off the river can create a challenge to say the least.

HA! Just GETTING to eastern Washington from the Snake river valley is more work than Spokane to the top of the east side of Snoqualime, doesn't matter which way you go. :-laf

The only times I saw less than 10 mpg any time between Boise and Seattle I found a problem causing it. Just sayin'... .....

 

[JJPage]

HA! Just GETTING to eastern Washington from the Snake river valley is more work than Spokane to the top of the east side of Snoqualime

Not sure what you want to dispute, the Lewiston hill is formidable, it is like all of eastern wa. northern id.

I have never acheived 10 mpg towing, if you have, let us in on your secret

 

[NIsaacs]

It did take me 41 days to use 25 gallons however .

Maybe some evaporated in that time frame



Nick

 

[cerberusiam]

Not sure what you want to dispute, the Lewiston hill is formidable, it is like all of eastern wa. northern id.

I have never acheived 10 mpg towing, if you have, let us in on your secret

Not disputing anything just comparing. Either way you go from Boise, up 95 from Payette to Pullman or Ontario to Pendelton, once we got to eastern Washington the pull was always easier. Always saw better fuel mileage in that leg. Comparatively speaking, Spokane to Ellensburg is relatively flat. Thats all. The wind in area west of the Rockies can be a big factor and on a large frontal area trailer it is a drag.

As for mileage, a little power, a little timing, and judicious driving seems to be the ticket for decent fuel mileage. Stock in bad conditions like cold and wind it was less than 10 with loads ranging from 6-12k but I was running 68-70 mph all the time. Even grossing 22k and driving from Seattle to North Carolina on the osuthern route the worst was 9. 5 and that was my wife relying on CC. Once she quit using that and drove the truck it cam right back up around 10-12 depending on terrain and ambient temp.

A dually will make a differnce but not as much loaded as emoty, my experience anyway. Still, an SRW with stock gears, stock tires, stock power at the speeds the OP talks about and the weight SHOULD do better than 8. 7 on the run he was talking about in the conditions he had.

 

[TCDiesel]

Not disputing anything just comparing. Either way you go from Boise, up 95 from Payette to Pullman or Ontario to Pendelton, once we got to eastern Washington the pull was always easier. Always saw better fuel mileage in that leg. Comparatively speaking, Spokane to Ellensburg is relatively flat. Thats all. The wind in area west of the Rockies can be a big factor and on a large frontal area trailer it is a drag.

As for mileage, a little power, a little timing, and judicious driving seems to be the ticket for decent fuel mileage. Stock in bad conditions like cold and wind it was less than 10 with loads ranging from 6-12k but I was running 68-70 mph all the time. Even grossing 22k and driving from Seattle to North Carolina on the osuthern route the worst was 9. 5 and that was my wife relying on CC. Once she quit using that and drove the truck it cam right back up around 10-12 depending on terrain and ambient temp.

A dually will make a differnce but not as much loaded as emoty, my experience anyway. Still, an SRW with stock gears, stock tires, stock power at the speeds the OP talks about and the weight SHOULD do better than 8. 7 on the run he was talking about in the conditions he had.

X2, I drive the Rockies and the West ALL winter long with My Toy hauler, Two years Back I had to fight a head wind of 40/50MPH on 90 in SD My mileage was in the 5MPG,it was less cost (We had the Time) to stop and spend the night in Murdo. I have auxiliary fueling and HC every gallon, My Average is 10/12 MPG when Tow HWY, My Summer Construction Mileage is 9/11 city. At 1 time We had Gas V-10s Average Mileage 5/8MPG City.

 

[NIsaacs]

AH, I'm believing you obtained this info about the OP's area of travel from some map...





JJ, I think AH was talking about one of his own hauls, not the OP's.



Nick

 

[AH64ID]

AH, I'm believing you obtained this info about the OP's area of travel from some map...

That was a personal note on mileage towing a 8. 5K TT at 17. 5K-18K GCW.

When leaving Spokane heading west into the rolling, treeless hills, there is nothing to stop the wind. As you approach to the Columbia River, the hills get longer and higher, nothing relatively flat about it. Ryegrass/Vantage may only be 5% for the last mile, but it is 10 miles long travelling west, and the wind currents coming off the river can create a challenge to say the least.

When I was still driving, I used to meet the other driver from Kent at Vantage to swap doubles, the wind would be blowing so damn hard it could rip the driver's door out of your grasp trying to get in or out of the rig. Lost my hat one night, really had to hang on to bill of ladings or they would disappear. I understand the OP did not realize any wind that particular day, doesn't mean it wasn't a factor.

Ryegrass has been the subject of discussion on this forum in the past, it really is shrugged off as insignificant, but I have seen many vehicles off on the shoulder with either steam or fluids running out of them.

I know the I-90 corridor well, and while I haven't towed my TT on it I have towed across I-90 from Bozeman to Seattle at about 15K and the leg between Spokane and Seattle is the easiest.

The wind thru that area is horrendous sometimes, just like here in South Idaho. A lot of people don't realize how much it effects mileage on a car, let alone a trailer with a big frontal area. I have a friend who took his wife's V8 4Runner to Spokane for some bird hunting, and on the way home he got about 12 mpg (4-5 worse than normal) and was ready to spend thousands of dollars because the motor had to have issues. I asked him about the wind, "yeah about 30-40 mph, but that won't hurt my mileage that much will it?" Yeah it will!

Ryegrass isn't that steep, but it is long. It's actually steeper on the E side of the river climbing away from Vantage. Ryegrass does leave many people stranded, but if the rig is mechanically sound its not too hard of a pull, just a long steady one.

To get my rig to dip below 10 towing my TT I have to be doing 70 with a headwind, or crossing Teton Pass. Otherwise I am always above 10.

 

[NIsaacs]

That was a personal note on mileage towing a 8. 5K TT at 17. 5K-18K GCW.



To get my rig to dip below 10 towing my TT I have to be doing 70 with a headwind, or crossing Teton Pass. Otherwise I am always above 10.

Thats about what I find with my '01. On a 2500 mile round trip to Montana in August my average was 11. 82 towing my F250 4x4 about 17,000 GCW. If I am hauling hay, bigger/heavier load, it can go down to 6-8.



Nick

 

[JJPage]

I have never acheived 10 mpg towing, if you have, let us in on your secret

This is only true while pulling my 5ver@14k, I have made 11-14 mpg with my small enclosed trailer(7k max).

Back to the OP's original inquiry, I don't believe his calculations are abnormal, could they be better?, sure. I wouldn't start borrowing trouble or replacing parts just yet...

 

[Edd Wadsworth]

OK, I've been reading this thread with great interest. It looks like I should be able to do a little better hauling. Is there anything I can do to this stock system to increase mileage that will pay me back for doing it? I have a friend that has a '96 that he modified the transmission so that he can have lock up in each gear. Don't know the cost but it sounds inticeing - it seems like making a manual out of an auto.



My old '02 2x4 with a 6 spd pulling the same trailer would make 11+. Sounds like maybe I should have kept it.

 

[cerberusiam]

A little more power and a little timing can make a large difference. Lockup in the lower gears is not going to help your mileage towing much where a better TC will help get the power down and you spend less time in the throttle over all but the bulk of the mileage will be made at steady speeds. You really don't want to add lockup controllers to these trucks without billet input shafts. Stock they have enough TQ to twist OE pieces, powred way more than enough.