Just went from Pacifica ca to Chillicothe mo and averaged 12.5 hand calculated ... He351cw turbo held well and power on demand with juice hot. Will be doing studs , 62 ii turbo and a 15 gallon methanol tank in back soon. ... Maybe a cam10000 pounds loaded .... 5th wheel ... Only had to downshift due to egt most of time ... ;)

What speeds were you running?

What speeds were you running?

Mostly 60-65 Need to get my methanol setup so I can stay in OD longer !!! Didnt have it tuned in properly - so didnt run it.

My last big haul a weighed 22.7k ran 65, occasionally 70(55 when the limit drooped), and got 10.2 hand calc. i know the weight is a factor, but i cant help but believe pulling that billboard thru the air is the biggest factor. i came over the Blue Ridge mountains and had to down shift to 5th for the grades but mostly stayed if 6th. my egts stayed in check, the Banks is suppposed to monitor that and no let go over 1300*. i mostly saw on longrades egt's of 1100 to maybe 1200. but i would take 12.5 mpg any day. I am not unhappy with 10.2 beings my 5th wheel is almost 13' tall.

Dave, I have a friend with an 08 F450 pickup truck with the 6.4 diesel. He would die and go to heaven to get 10.2 RUNNING EMPTY. He gets an average of 8 mpg (empty). He paid $55K for it and refuses to sell it because he doesn't want to take a huge loss on it. (wakey wakey, it's already happened) He loves the way it looks, hates the fuel mileage so much that he won't drive it. I guess that is the definition of a true "Love, Hate relationship" Back on topic...These old trucks do very well on fuel considering what they pull, and how many miles are on some of them.

Dave, I have a friend with an 08 F450 pickup truck with the 6.4 diesel. He would die and go to heaven to get 10.2 RUNNING EMPTY. He gets an average of 8 mpg (empty). He paid $55K for it and refuses to sell it because he doesn't want to take a huge loss on it. (wakey wakey, it's already happened) He loves the way it looks, hates the fuel mileage so much that he won't drive it. I guess that is the definition of a true "Love, Hate relationship" Back on topic... These old trucks do very well on fuel considering what they pull, and how many miles are on some of them.

No need to get rid of the truck, just the motor!

If you can find it under the plumbing:lmao2:. That is another reason i love it, open the hood i can see the engine front to back, both sides. it runs, pulls, and gets better milage than when it was new. Upgrades have provided the mileage, but the rock solid engine has provided the foundation for that.

Dave, I have a friend with an 08 F450 pickup truck with the 6.4 diesel. He would die and go to heaven to get 10.2 RUNNING EMPTY. He gets an average of 8 mpg (empty). He paid $55K for it and refuses to sell it because he doesn't want to take a huge loss on it. (wakey wakey, it's already happened) He loves the way it looks, hates the fuel mileage so much that he won't drive it. I guess that is the definition of a true "Love, Hate relationship" Back on topic... These old trucks do very well on fuel considering what they pull, and how many miles are on some of them.

We have pretty much the same truck at work, 08 F450 4dr with a flatbed, i reset the avg mpg calculator (not sure how accurate it is) and drove it about 60 miles 90% highway unloaded the whole way and showed an average of 7.6mpg when i pulled back into the yard at work -Jordan-

something seems way wrong here, i towed a 14,000lbs empty 5th wheel camper and averages almost 15mpg?(well 14 and change):tongue:im really curious as to if the transmission makes a difference.:shrug:And if my 99 got 12.5mpg ide retire it for my 08 dodge that gets the same towing 20,000lbs

I have never seen over 10.3 in mine since it was new. How fast are you driving to get 15?

My last haul of the season I was pulling 14.1 MPG hand calculated for the trip with 16,080# GCW. (~7,800# Trailer)Speed is still a huge factor in trailer hauling wind drag is still wind drag and RV is a huge box rolling down the highway cutting through the wind. I normally tow at 55-60 MPH. I know that Idaho laws states that no trailer maybe towed any faster than 65 MPH (PERIOD!). This is utility trailer, RV, or semi-trailer... Also Idaho laws states that there is no minimum speed limit so I may travel as slow as I personal want or what is safe for weather / road conditions. Also most all trailer tires (ST's) are rated for only 65 MPH beyond this your asking for a blow out! So what is it going to hurt cutting 10 MPH off my speed and relaxing while I haul my RV to it next destination? Less chances of a tire blow out. Better MPG's. Lower EGT's. Less stress on the driveline...

I do agree with what you are saying. That is why I asked pepsi how fast he was driving. If I am traveling the Interstate I run the speed limit, be it 55 or be it 70. I know slowing down will help with the mpg with less wind drag and speed. Most of my trips start on Friday afternoon and have to be at work on Monday morning so a sacrifice of mpg for less time on the road is personal choice i am willing to make.

As Mike stated, both speed and aerodynamics play a role in fuel mileage. Speed because mathematically the drag coefficient of a vehicle increases exponentially. Meaning it takes four times the HP to double the speed. So you can only imagine how much more fuel it takes to go from 55 to 75 MPH. This is all exaggerated while towing because of increased rolling resistance from the combined weight and the extra drag from whatever you're towing. TT's and 5th wheels are generally anything but aerodynamic so you're really just shoving them down the road. The more aerodynamic the trailer is and the amount of energy it takes to move it along will reduce. I can tow a heavy boat down the freeway and not even know its there but when towing a travel trailer, I rarely need to use the brakes because letting off the throttle slows me fast enough. Now some engines are simply more efficient at a certain work load and the Cummins excels in that department which is why we get such great fuel mileage. All engines can tow but how hard they have to work to accomplish the same task is whats important.

Now some engines are simply more efficient at a certain work load and the Cummins excels in that department which is why we get such great fuel mileage. All engines can tow but how hard they have to work to accomplish the same task is whats important.

god bless the inline 6! they are inherantly torque monsters! my bmw323i was an I6 and it had gobs of torque!

I have never seen over 10.3 in mine since it was new. How fast are you driving to get 15?

typically 58-60 in 4th gear. or 50-54 in 3rd. (i don't have a boost gauge but i try to keep my pyro's around 800-900. now going up hills or accelerating are different, but in general that is where i stay.

I tend to leave the smarty on level 3-5 depending on what im hauling it helps alot against the downshifts.

My last haul of the season I was pulling 14.1 MPG hand calculated for the trip with 16,080# GCW. (~7,800# Trailer)

Speed is still a huge factor in trailer hauling wind drag is still wind drag and RV is a huge box rolling down the highway cutting through the wind. I normally tow at 55-60 MPH. I know that Idaho laws states that no trailer maybe towed any faster than 65 MPH (PERIOD!). This is utility trailer, RV, or semi-trailer... Also Idaho laws states that there is no minimum speed limit so I may travel as slow as I personal want or what is safe for weather / road conditions. Also most all trailer tires (ST's) are rated for only 65 MPH beyond this your asking for a blow out! So what is it going to hurt cutting 10 MPH off my speed and relaxing while I haul my RV to it next destination? Less chances of a tire blow out. Better MPG's. Lower EGT's. Less stress on the driveline...

This:smart:

Yeah I have never tried slowing down to 55 -- mainly as in od I am lugging the engine at that speed guessing around 1400rpm ...

Yeah I have never tried slowing down to 55 -- mainly as in od I am lugging the engine at that speed guessing around 1400rpm ...

if im running 55 i'll usually be in 3rd and drop down to 50-54 ish, anything over 58 i find the truck has no problems. then again im running about 1,600 rpm's at 55, and almost 1,800 at about 60. in 3rd i run about 1,800-2,100 rpm's. i find it pulls very hard around here and you can still make headway, i tend not to run in this gear unless i need to or reasons require it. i suspect once my dtt trans wears in the rpm's will change when i start hauling with it. i already like the way it drives.

From about 1,500 to 2,000 RPM's is your torque curve pass 2,000 RPM the torque start heading down hill on most trucks and the HP starts to flatten out some. Remember this is just rule of thumb guys/gals... I know some of you can provide dyno sheets with torque going well into the 3K catagory.

1800 to 2100 is a good cruising rpm for me. i will go higher when pulling a grade, maybe 2500 or 2600. It all just depends on the situation I find myself. No dyno sheets here, Ijust do what feels right.

I find mine pulls the strongest at around 2200 RPM which happens to be around 55-60 mph in 4th. Thats not to say that 1700-2199 isn't also impressive but just noting where it will pull just about any hill with any load (I've had) without much, if any, speed loss.

saw on a CF thread someone disconnects the front driveshaft on their 4x4 to pickup another 1;.5mpgwonder how that helps if the TranCase is in 2 hi ?