Diesel Motorhome MPG-- Honest Answers Please

[manholt]

Then there is the rotation of the Earth...kid you not...I get around .4 mpg (6.8) better between West Coast and FL., than the opposite direction (6.2)!!!  Fuel now is avg., $2.75 in Texas!  6 weeks ago, it was $2.27..

[wayne77590]

The previous 2008 Winnebago Destination was between 8.2 and 8.9 consistently as averages depending on the wind.  Cummins ISB 340, Alison 2500. GVW 27,400, Towing 2007 Saturn and then 2013 MKX

The new to us 2015 Winnebago Tour 42qd, Cummins 450, Alison 3000, GVW 45,660, on the few trips taken, has been between 7.2 and 7.9, towing 2013 MKX.

The palm tree was cut down yesterday.

 

 

[wildebill308]

Nice, You are lucky to be able to park at your house.

Bill

[punxsyjumper]

2 hours ago, manholt said:

Then there is the rotation of the Earth...kid you not...I get around .4 mpg (6.8) better between West Coast and FL., than the opposite direction (6.2)!!!  Fuel now is avg., $2.75 in Texas!  6 weeks ago, it was $2.27..

That would be reversed if you were south of the equator

[wayne77590]

MPG is real good sitting there, but I'm ready to hit the road and see if I get better mileage.

It would be in the back yard if I could convince DW to cut down the very large oak tree.

[jleamont]

Wayne that MPG is good, probably get better as it breaks in. coach is beautiful, love the property also. 

[wayne77590]

Well not much to do with MPG, but, while we had the 2008 I had the driveway redone as it was all cracked. Early 1960's cement and the support was chicken wire and all of it was on the bottom of the driveway.  Had 3/8" rebar and 6" of cement for the new one. Expanded it 26 inches on the sidewalk side and 19" on the edge of the house side. Had 8" piers on the edges.  Now when I park with the new one I can leave 6-8 inches on the sidewalk side and extend the driver slide with a little left over before center of garage. DW can move her car in and out and I can leave the slide out.  Very happy with the outcome.  I have 50 amp outside the garage.

With only 14,000+ miles on the MH I'm happy with the 7.2 to 7.9 and hoping that once it is really broken in it will increase a little. I'd be happy with between 8.2 and 8.9.

Jim S and I went to Gaffney several years ago and before we hit the hills of Alabama there was a segment where we got 12 MPG on our old coaches.

[desertdeals69]

14 hours ago, manholt said:

Then there is the rotation of the Earth...kid you not...I get around .4 mpg (6.8) better between West Coast and FL., than the opposite direction (6.2)!!!  Fuel now is avg., $2.75 in Texas!  6 weeks ago, it was $2.27..

I think there is more headwind when you go west.

[wayne77590]

Oh yes!

[five]

The winds at altitude are always west to east...that's why the flight times from LAX to ATL are faster than ATL to LAX.

[TimeTraveler]

On 4/21/2018 at 10:59 AM, Punxsyjumper said:

That would be reversed if you were south of the equator

I notice when I jump off the hill which is facing west I get to the bottom a little further out before busting my bottom too.

May be on to something here. Maybe we could travel west at night when the moon is going full and its pull cut fuel consumption

[wildebill308]

On 4/21/2018 at 1:18 PM, wayne77590 said:

MPG is real good sitting there, but I'm ready to hit the road and see if I get better mileage.

It would be in the back yard if I could convince DW to cut down the very large oak tree.

Wayne, try using Diesel Kleen to improve the cetane rating of your fuel. I can tell the difference of how smooth the engine runs with it.

https://powerservice.com/psp_product/diesel-kleen-cetane-boost/, "Diesel Kleen +Cetane Boost is loaded with cetane, detergent and lubricity improver to provide peak diesel performance."

Bill

[kaypsmith]

On 4/21/2018 at 8:51 AM, manholt said:

Then there is the rotation of the Earth...kid you not...I get around .4 mpg (6.8) better between West Coast and FL., than the opposite direction (6.2)!!! 

Carl, you just have more hot air going in that direction, not many beans in Florida!!!

[struthers495]

I've only ran a few tank fulls thru of my 'new to me' RV but we have documented 13 to 15 mpg.  2011 H/R  Trip with a 260 hp front engine diesel, no DEF, not towing, cruising at 60 mph.  Weight = 22,200 lbs.

Areodynamic,  light on the pedal.  I do use a cetane additive.

[desertdeals69]

26 minutes ago, struthers495 said:

I've only ran a few tank fulls thru of my 'new to me' RV but we have documented 13 to 15 mpg.  2011 H/R  Trip with a 260 hp front engine diesel, no DEF, not towing, cruising at 60 mph.  Weight = 22,200 lbs.

Areodynamic,  light on the pedal.  I do use a cetane additive.

Is your odometer certified accurate?

[wildebill308]

3 hours ago, struthers495 said:

I've only ran a few tank fulls thru of my 'new to me' RV but we have documented 13 to 15 mpg.  2011 H/R  Trip with a 260 hp front engine diesel, no DEF, not towing, cruising at 60 mph.  Weight = 22,200 lbs.

Areodynamic,  light on the pedal.  I do use a cetane additive.

What is your average for 10 fill ups? 

Bill

[manholt]

No DEF on a 2011 coach?  Did you buy a 2009 Cummins and swap out engines?  Cetane don't do much, since you don't get enough of it, in a bottle of additive.  Believe that was discussed and proven early last year!

 

[wayne77590]

Carl, I'm not sure but I don't think twin turbos need DEF. 

Looked a a Knight, later than 2010 and it did not have a DEF tank but it had twin turbos.

Someone enlighten me on this.

Struthers runs a twin diesel.

[jleamont]

8 hours ago, manholt said:

No DEF on a 2011 coach?  Did you buy a 2009 Cummins and swap out engines?  Cetane don't do much, since you don't get enough of it, in a bottle of additive.  Believe that was discussed and proven early last year!

 

Its an International Maxxforce 7 V8 diesel. Those MPG's are impressive in a motorhome when the pickup truck that engine was in couldn't get 9

[rsbilledwards]

Late to the party but now back home after 9,000 miles of pure unadulterated freedom of being on the road since the first of January. Typical mileage towing the Chevy Tracker 3,300 pounds, rolling between 62 and 65, RPMs in the 1325 + - range, C12 425 HP CAT, Allison 4060, weight under 31,000 pounds, so 34,300 + - pounds equalled 8.5 MPG average. One 300 mile section across Texas on I 20 we saw double digits as high as 15 MPG. Add in the propane and we averaged 9.6 with the 1 gallon per 100 miles as advertised when I had it on. Some what of a guess as the frige was useing it too and for a while it used more than it should have. I filled the tank 3 times, about 100 gallons. 

[manholt]

BillE.  Welcome back to our Family Forum!  Sorry we where unable to connect in March, Linda was hoping to be with your better half again!

[jleamont]

11 minutes ago, rsbilledwards said:

Late to the party but now back home after 9,000 miles of pure unadulterated freedom of being on the road since the first of January. Typical mileage towing the Chevy Tracker 3,300 pounds, rolling between 62 and 65, RPMs in the 1325 + - range, C12 425 HP CAT, Allison 4060, weight under 31,000 pounds, so 34,300 + - pounds equalled 8.5 MPG average. One 300 mile section across Texas on I 20 we saw double digits as high as 15 MPG. Add in the propane and we averaged 9.6 with the 1 gallon per 100 miles as advertised when I had it on. Some what of a guess as the frige was useing it too and for a while it used more than it should have. I filled the tank 3 times, about 100 gallons. 

Hey stranger! You noticed an increase with the propane injection?

[wildebill308]

Interesting, Propane is the only mod that I haven't tried. Where is that section in Texas with a long downhill and a big tailwind.

Bill

[rsbilledwards]

20 across the state was very flat and the section was about 300 miles long could have been favorable wind? I do not recall any hills large or small on 20 running west but it was pretty and green. I did not expect that border to border. I did just finish reading a book Empire of the Southern Sun about the comanche Indians and their rein of terror across Texas during the settlement of the West., fascinating and now I understand.   It was a pulitzer Prize finalist and well documented. 

Yes there was a difference and the exhaust much cleane when you but the foot down.

 

[five]

All things considered, a strong head wind is the worse detriment to good MPG...it's like having a ping pong table strapped to the front.