Fuel Mileage - Diesel vs Gas

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Bill N

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I have been meaning to ask this for a while.  Never had a diesel vehicle.  Our coach is gas powered.  I notice that there is a pretty large difference between gas and diesel prices these days.  My question is, apart from the other advantages of diesel, is the mileage per gallon good enough to make up for the difference in price?

Bill
 
Bill N said:
My question is, apart from the other advantages of diesel, is the mileage per gallon good enough to make up for the difference in price?

No. At truck stops during a recent trip I noted diesel prices were as much as 45% more than gas. At smaller stations it's typically at least 15-20% more (although I've seen as little as a 10% difference, but rare).

And the cost of a diesel rig is not just the initial purchase price difference, there is also the ongoing maintenance costs. A pusher diesel is a great machine, and can run wide open all day without breaking a sweat. Plus it's nice and quiet with the engine 30+ feet behind you. And you will recover some of the higher purchase price when you go to sell. But I would base a purchase decision on need and perhaps desire, but not because you think fuel savings will reach a breakeven point.

The same goes for pickups. I have a friend pulling with a diesel pickup. He reports 9-11 while pulling vs. 7-8 for my gas truck, and 18-19 while not pulling vs. 14-15 for my gas truck. So while he enjoys 30% greater 'economy', it's pretty much a wash because he pays about that much extra for fuel. But if you're pulling in the mountains, and/or pulling a heavy trailer, diesel is probably the way to go regardless.

(FYI, just moved from diesel Dutch Star to gas powered tow vehicle, not for fuel economy reasons.)
 
Thanks Scott.  You pretty much confirmed what I thought to be the case.  Around here Diesel generally runs .75 to 1.00 higher per gallon than gas.  Diesel pickups never interested me since I drove them on the farm - just flat out noisey and smelly but at the back end of a motorhome they are a delight.  I used to be a drivers license examiner and did road tests on drivers from an MCI bus plant in North Dakota.  Those things were so quiet you barely realized you were being propelled by an engine.  Thanks again.

Bill
 
They have Rene.  Workhorse built one called a Universal chassis that had a rear engine.  Apparently it wasn't a success and they only produced them for a few years.  Didn't know much about them but based on the short history they probably weren't big seller. 
 
A rear engine layout is more expensive than front engine, so rear gas coach is inherently more expensive than front gas.  Buyers with a larger budget want more than just rear engine - they are into the entire package of a diesel pusher - air suspension & brakes, larger carrying capacity, etc.  The rest seem to be driven more by price than capability.  Workhorse & Freightliner Custom Chassis have tried both front diesel and rear gas, but engine differences alone were not sufficient to motivate RV buyers.  They cost more without enough perceived benefit.


Tiffin tried for a couple years to make a success using the Freightliner FRED front diesel, but could not get enough buyers to pony up the extra price.  Most buyers went all the way to a pusher instead.  Winnebago tried with the rear gas, but no luck there either. However, it wasn't a real  good trial because Workhorse never got all the bugs out of their rear gas chassis so most were delivered with a Cummins diesel anyway.
Diesel power comes into its own as the rigs get heavier, say north of 25,000 lbs (dry) or 30,000 lbs GVWR.
 
Rene T said:
I've often wondered why they don't put gas engines in the back of MH's.
Rexhall also did it , big block Chevy and an Alison trans.
 
The question of fuel mileage always cracks me up, it has nothing to do with gas vs. diesel and everthing to do with your ability to afford the cost regardless of fuel type.. Buying fuel for an RV (any type) just aint cheap enough for some folks.>>>Dan
 
Utclmjmpr said:
The question of fuel mileage always cracks me up, it has nothing to do with gas vs. diesel and everthing to do with your ability to afford the cost regardless of fuel type.. Buying fuel for an RV (any type) just aint cheap enough for some folks.>>>Dan

That may be true for some but hardly true for everyone.  There are many diesel owners on this forum who started with a gasser. 
 
I realized immediately that RVing had next to nothing to do with fuel economy. Or a wise financial decision. Or saving money (rarely).  But it has everything to do with adventure, exploring what's around the next corner, freedom to go where and when you choose, and being surrounded with all your own stuff when you get there.  20+ years and I wouldn't trade it for anything.
 
Broke Boater said:
What is the access to those MH with front mounted gas engines? I remember a buddy had a ford van with a v8 and was not fun working on it,,,gregg

You can get to everything, you just have to remember the engine has a bottom as well as a top side.  For example, spark plugs can be a bear to get to from the top, but they're front and center if you crank the front wheels all the way over and sit upright in the wheel well.  Same for things like the power steering pump, etc.

Replacing the water pump may involve pulling the radiator out the front first, then there's plenty of room.
 
In addition to the advantages mentioned above, a pusher diesel can use the truck pumps rather than contorting around the car pumps. That is a significant convenience, but saving on fuel is not a motor home feature.

Ernie
 
Fuel Mileage - Diesel vs Gas. We see this question almost mounthley. There is no real legitimate comparison unless you can compare the same RV with a gas engine or the same with a diesel engine. Moste diesel coaches are heavier than gas coaches. When someone says they get 10-12 mpg in a small gas coach and compare that to the mileage of a diesel coach that is getting 7-8 mpg sounds pretty good till you understand the gas coach may weigh 18,000 pounds and the diesel is 55,000 lbs.
The diesel also produces peak torque at lower rpm than a gas engine.
Bill
 
I started this thread only to ask a simple question about why diesel fuel is so much more than gasoline at the pump.  'Back-in-the-day' if I recall correctly diesel was always cheaper than gasoline.  My main thought was that maybe the increased cost was related to better fuel mileage or whatever. So now I have my answer  - Diesel fuel costs more than gasoline - Period.  I used to think that maybe one reason for the increase in diesel price was due to the government requiring certain specs for highway use diesel fuel (I read that on a sticker at the diesel pumps as I am filling up my gas car).  Anyway, thanks for the education folks.  If I had the bucks I would have a diesel coach but that is not to be.  After another birthday yesterday I am wondering if I will have a coach at all much longer.  Can't justify it just to say I have one because it sat in storage for 11 months this past year and come Jan 1, a new personal tax year begins. Yikes.

Bill
 
I have seen diesel priced about the same as gas in a few areas.  State taxes on the two types of fuel vary greatly and you need to understand that you are buying fuel and buying taxes and keep those figures separate when trying to understand how fuel is priced.  The regulations on sulfur and ethanol has a great effect on the final price as well.
 
Latest price differential, as-of today (GA)
 

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Back2PA said:
Latest price differential, as-of today (GA)

Depends where you buy, as always.

 

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