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Discussion Starter #1
I filled my tank at 110 miles, drove 325 miles since then and refilled. My calculation gives me slightly over 18 mpg in combined driving (about 1/3 highway.) I know I need a couple more tankloads to even out the readings but the onboard computer tied to that figure almost exactly. And I'm still in the break-in period. This gives me hope that pure highway will give me 20+ mpg, that's quite an improvement from my Ford F150 & trailer combo that was lucky to get 9 mpg with a tailwind. I still haven't introduced the 1,500-2,000 lb. load that I will be hauling around but I have read that it probably won't make that much of a difference (maybe 1-2 mpg.) So far I'm happy with the mpg!


Oh, and btw, I'm very happy with the pep this engine has (unloaded anyway.)
 

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.....cut......

I still haven't introduced the 1,500-2,000 lb. load that I will be hauling around but I have read that it probably won't make that much of a difference (maybe 1-2 mpg.) So far I'm happy with the mpg!
Thanks for update.

That estimate sounds about right to me if you are referring to mostly highway driving at normal speeds. Added weight typically increases rolling resistance by "approximately" 20 pounds for every ton, so the added +/- 20 pounds to total resistance should reduce mileage in that range. One factor that may drop MPG by more would be if the added load causes the transmission to downshift much more often on hills. However, I can't imagine that 2000 extra load would force downshifts often enough that it would impact fuel economy significantly when averaged over 1000s of miles. Not unless you drive mostly in hilly areas.

During city driving increasing your van's mass from around 5000 pounds (empty) to about 7000 pounds should make a bigger difference.
 

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Discussion Starter #3
During city driving increasing your van's mass from around 5000 pounds (empty) to about 7000 pounds should make a bigger difference.
Most of my driving will be highway or at least countryside, with not many stop signs or lights, so I won't suffer too much from having to start from zero with the load too often. It is somewhat hilly tho - we'll see how much that affects the mpg when I am fully loaded.

One thing that bothers me however is how the tranny automatically downshifts on steeper downhills when I don't want it to, I want it to stay in 6th for the best mileage - anybody notice that? My F150 didn't do that...
 

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Your MPG sounds like it is doing pretty well. Its good that it is matching up with what Ram says it should do.

You'll have to report back once you have tried it out with the cargo weight added. I feel like an extra 2,000 lbs must make a bit of a difference.

Can't believe your old Ford got 9 MPG. Thanks gosh you don't have to use that anymore.
 

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One thing that bothers me however is how the tranny automatically downshifts on steeper downhills when I don't want it to, I want it to stay in 6th for the best mileage - anybody notice that? My F150 didn't do that...
Are you worried about downshifts on "downhills", or did you mean to say up hills?

Downshifting on downhills for engine braking doesn't use all that much fuel because the engine, while spinning very fast, has the throttle closed, allowing very little air into engine. And little air requires little fuel.

I wouldn't even worry to much about uphill downshifts as long as you are driving normally. Engine efficiencies are relatively constant over a wide RPM range. What needs to be avoided is running the engine at high RPM and low load. But if van downshifts out of necessity then it can't be at low load, right? Its nothing to worry about as it affects fuel economy.
 

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Discussion Starter #7
Are you worried about downshifts on "downhills", or did you mean to say up hills?

Downshifting on downhills for engine braking doesn't use all that much fuel because the engine, while spinning very fast, has the throttle closed, allowing very little air into engine. And little air requires little fuel.
/QUOTE]

I did mean downhills, it is automatically engine braking when I don't want it to. It suddenly is running at 2,500- 3,000 rpm because it downshifted when, if it stayed in 6th, it would probably be at 1,000 rpm or even below. My F150 never downshifted on downhills like that so on steep downhills that baby would really get moving!

But you say that even tho the engine is spinning fast it's not using much fuel? I hope that's true but I still am using more fuel because now I'm not going as fast when I go uphill on the other side, hence more fuel needed to climb...
 

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Discussion Starter #8
Can't believe your old Ford got 9 MPG. Thanks gosh you don't have to use that anymore.
That was while pulling the trailer. But it never got more than 15 even on open highway, summer, tailwind, no trailer - it really sucked (gas.)


It also was a total rust heap when I traded it in, the bed was virtually gone and the side panels weren't much better. It was a 2002 for those who are curious.
 

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Are you worried about downshifts on "downhills", or did you mean to say up hills?

Downshifting on downhills for engine braking doesn't use all that much fuel because the engine, while spinning very fast, has the throttle closed, allowing very little air into engine. And little air requires little fuel.
I did mean downhills, it is automatically engine braking when I don't want it to. It suddenly is running at 2,500- 3,000 rpm because it downshifted when, if it stayed in 6th, it would probably be at 1,000 rpm or even below. My F150 never downshifted on downhills like that so on steep downhills that baby would really get moving!

But you say that even tho the engine is spinning fast it's not using much fuel? I hope that's true but I still am using more fuel because now I'm not going as fast when I go uphill on the other side, hence more fuel needed to climb...
If the van is downshifting to slow down or to hold a speed below what you want to travel at, wouldn't giving it a little gas solve your problem? If you give it enough gas it should even accelerate downhill. The automatic downshift is there to prevent drivers from having to ride their brakes, but it shouldn't slow your speed below desired by driver.

You are right in that there is no need to slow down excessively and lose momentum if you can maintain a higher safe speed going downhill. I drove a rented Ford RV van with TowHaul and it did something similar which was annoying on some downhills. I got around it by taking it out of TowHaul or else stepping on gas to get going. As soon as it sensed I didn't want to go slow the transmission upshifted.

By the way, as I stated in another thread, I got highest MPG during my 5000-mile trip while driving in the mountains. And the same happened with my own RV years earlier or with my present Ford van. Hills and mountains don't necessarily reduce fuel economy, particularly if road conditions cause average speed to be much lower.
 

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Discussion Starter #11
If the van is downshifting to slow down or to hold a speed below what you want to travel at, wouldn't giving it a little gas solve your problem? If you give it enough gas it should even accelerate downhill. The automatic downshift is there to prevent drivers from having to ride their brakes, but it shouldn't slow your speed below desired by driver.

I got around it by taking it out of TowHaul or else stepping on gas to get going. As soon as it sensed I didn't want to go slow the transmission upshifted.
Thanks Chance, I'll try the slight acceleration thing to try to kick it out of the lower gear to see if that works.
 

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Just turned 55,000 and getting 20.4 by dash calculations. Running it as an expeditor.
2500 with sleeper. New it was in the 18 range.
 
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