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Question 2024 Dutchstar fuel economy

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kevin,
I have often wondered and come to the conclusion that fuel burn for the generator is not included in the MPG registered on the dash. Do you concur?
No, the dash MPG is only based on fuel thru the engine. You can either go by the dash MPG, or you can do tank to tank vs traveled miles and guestimate generator and oasis consumption based on operated hours and published approximate consumption rates.
 
kevin,
I have often wondered and come to the conclusion that fuel burn for the generator is not included in the MPG registered on the dash. Do you concur?
Yes I do!!!
 
No, the dash MPG is only based on fuel thru the engine. You can either go by the dash MPG, or you can do tank to tank vs traveled miles and guestimate generator and oasis consumption based on operated hours and published approximate consumption rates.
This! I really had not concerned myself with in my answer. However that also, makes a very large case for using the computers display for fuel mileage, as generator use and oasis heating would skew MPG numbers caused by using fuel fill calculations.

That said the two calculations could be used to determine house energy usage!!!
 
Fuel economy is a nice to have number. When an application starts to vary from average with no obvious change in use, it might be that something needs attention.
Using more fuel for the same work is not a “good thing”.
This is the primary reason I follow fuel economy closely. When fuel economy starts to trend down something is wrong.
 
I don't know how much "space" foam displaces but IMHO if you want to get an accurate mileage assessment, you should slow fill to full avoiding foam, drive a route that's near level and get the fuel level as low as you can stand, then slow fill again to avoid the foam, then measure your result. I think we all know it's something around 7 for these beasts, beyond that I stop counting or worrying. The biggest thing is trusting your fuel gauge. This last leg home I had to put that trust to work and arrive at the fuel station in "ding" mode (low fuel alerts) and even still, I had 20 gals (out of 100) remaining after a slow fill. Mine calibrated/checked good. I did have to have a sending unit (or something along that line) replaced about two years ago from the fuel gauge going wonky on me.
Not exactly apples to apples,but my prior coach with the isx,started brand new around 6.7 mpg average,by the time it was broke in,and at 45k miles,the tripometer b that had never been reset,actually moved to 6.8 mpg,and by that time checking each tank of fuel,I was averaging about 7 mpg….by far the biggest factors I’ve noticed….how heavy is your right foot,and even more of a factor wind…ive found a sidewind hurts mileage much more than a headwind…and of course hilly terrain…..if my computer said I had used x amount of gallons,assuming little generator,oasis run time…..it was accurate within 1-2%…unbelievably accurate,often exact in fact…..
 
Hi Joe! If I reset my mileage meter when I start out, and I drive for 5-6 hours (in Florida), I'll finally get to where the meter is showing 7. So I would say you're probably getting pretty good mileage. :)
I hope you folks aren't depending on the display mpg. These are seldom accurate and usually show more mpg than what is real. Hand calculations are the only way to get your true mpg.
 
I hope you folks aren't depending on the display mpg. These are seldom accurate and usually show more mpg than what is real. Hand calculations are the only way to get your true mpg.
Well crap, there went any hope I had, however delusional, for breaking the big 7.
 
I do my own calculations so I can apply a calculation curve so I feel better. :geek:
 
I hope you folks aren't depending on the display mpg. These are seldom accurate and usually show more mpg than what is real. Hand calculations are the only way to get your true mpg.
I fully expect this from any four wheel vehicle sold by pretty much anyone. They lie and despite the fact they could be made to read true, they don't, lack of accountability does a lot in empowering auto manufacturers to constantly lie to their customers. I expect more from a company like Freightliner, their customer base is only shopping for one thing, not like the masses that could be cross shopping a Civic and a light duty "Super Duty" truck.
 
I hope you folks aren't depending on the display mpg. These are seldom accurate and usually show more mpg than what is real. Hand calculations are the only way to get your true mpg.
Over the years my display has consistently read right at 5% high on mpg reading. When it says I got 7.4 in actuality I got right at 7.
 
The only number I watch, and think important is the DTE, I travel in the mountains most the time, out west mileage is good before noon, then the winds pick up, everyday is different, it seems accurate enough for me, I always make it to the next stop, if I was that worried about MPG, I wouldn't be driving a DSDP, It's no worse than my F-450 pulling a 40' fifth wheel, guess I figure it comes with the territory
 
I ignore what the LBCU tells me and just calculate it. I don’t account for the gen and oasis either because in the long run its all mpg, but at least my way I have some control over how things are figgered.
 
I use 7 as a rule of thumb for calcs. In fact I divide my tank readings into miles. I have a 100 gal tank, that means 1/2 tank gives me 50x7 miles left. I start reaching for the brown paper bag at 1/4 tank, typically avoid getting to this point unless I know I have options such as the last leg of my last trip which went down to 20% remaining. So again, 1/4 tank, for me, means 150 miles until kaput. The low fuel warning dinging is so annoying you don't want to be in that below 1/4 zone. If you think you're going to calculate any distances based on 6.8 or 7.4 and rely on that, good luck, waiting for your story :)
 
Stuck in traffic with 1/4 tank😬

IMG_0928.jpeg
 
I'm in the school of not really thinking about my mpg. Whether I get 6.8, 7.2, or xx doesn't make much difference. I'm not changing my driving habits to get .01 mpg more or less. We all knew or should have known when we bought these beasts they are fuel hogs. I am towing a GMC Canyon p/u and I guess I could have chosen to tow some micro vehicle but I'm willing to pay the piper for the comfort of my truck. How many of you have been asked, "Is it cheaper to travel in your motorhome than flying and staying in hotels"? I usually stop them before they even finish with my answer, "There is nothing cheap about traveling in a motorhome".

We're leaving this morning for 4 days staying at various Harvest Hosts locations in the Texas Hill Country Winery areas. Whether I get 5mpg or 15mpg, we're still going.

I truly dread the day I have to hang up the keys so as long as I have my health and a few dollars in the bank, I'm going to enjoy what I believe is the greatest lifestyle there is.
 
I hope you folks aren't depending on the display mpg. These are seldom accurate and usually show more mpg than what is real. Hand calculations are the only way to get your true mpg.
Couple things here! It has been proven some economy car manufacturers mess with odometer so they can claim higher than real MPG! That said, In my previous post I included GPS in my argument. It is very important when calculating MPG that you calibrate your speedo!!! This can be done professionally, or comparing speedo numbers vs. GPS mile numbers. Keep in mind that tire wear will also change odometer readings.

For fuel injection controls accurate fuel numbers must be logged. Yes the O2 sensors and MAP/MAF sensors are always monitored as the biggest control values. However the computer also has many sensors it uses to adjust mixture for optimum performance, including odometer. It does this not only to keep your engine running right, but also to flag issues with the system for timely service.

The display of MPG is a reflection of this data, unmanipulated, and displayed.

Like mentioned in when do you add oil, no one can judge a perfect fill, and may be off by several gallons. No one I know today top of their tank to the top of filler port, so they can get a accurate reading. The flow sensors are much more accurate, so I trust them more for accuracy.

This is of course, is moot in the grand scheme of things. If MPG is going to break your bank, I must ask why you have an RV???
 
Our DS4369 was similar; High 6 to Mid 7's.

A few factors I've found that make a difference...aside from a 40mph tailwind LOL, are:

1. Driving 65 or under (HUGE difference; up to 20% on our 45')
2. Using PS DIESEL KLEEN (small difference...not convinced how much, but sure makes the starting easier)
3. PDI Tuner (maybe a slight bump of .5mpg)
 

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