Diesel vs Gas

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jwilson32

jwilson32

Member
Joined
Nov 21, 2009
Posts
7
Location
St. Louis
I'm in the market for a Class A motor home and still can't decide if gas or diesel is the way to go. I like the air ride, mileage, etc the diesel offers although the upfront cost, maint and fuel is a lot more.
I will be driving it 3-8K miles per year I'm guessing....

Thanks in advance,
Jordan
 
At 3-8k miles per year, you won't get any economic advantage from the diesel. But you will get the air suspension and other good attributes of a diesel pusher.  Gas chassis coaches from about 2002 on are excellent performers (GM 8.1L V8 or Ford v10 with 5 or 6 speed transmissions) and decent on gas (7-8 mpg). I'd look for a top end gas unit such as Fleetwood's Pace Arrow & Southwind or Monaco's LaPalma (gas) & Monarch SE.

Are you looking new or used?
 
3-8,000 miles isn't enough to reap many financial benefits but where will those miles be driven?  If you plan on going out west, you would appreciate the diesel more, I think.  Also, what size class A do you want?  Gas engines stop at about 37-38' which is pretty good sized but it you want 40' or more, it would almost have to be a diesel.  Would you plan on keeping the unit for a long time?  Diesel would be expected to be more valuable in ten years if you went to sell it. 
 
I couldn't afford the price of admission for a diesel with the floorplan we wanted vs a new 38p gas.  I definantly prefer how the DP's feel with their suspension & all that stuff but since we also figured we would put well under 10K miles a yr on the coach we went gas.  The only time I regretted not going gas was going up some of the mountains out west however it's a RV so no matter what I will not be able to climb the mtn as fast as any of my other motorized vehicles :) 

I talked to a few people in some of the camping areas we stayed at & it seems like many in the big DP's get about 8-8.5mpg & they all stated at any speed vs. 6-8mpg depending on my speed in the gas.

 
...it seems like many in the big DP's get about 8-8.5mpg & they all stated at any speed vs. 6-8mpg depending on my speed in the gas.
Click to expand...

No late model "big DP" is going to get that kind of mpg (though maybe it depends on what you call 'big") and speed is still a factor.  The newer diesel engines get poorer mileage, due mostly to pollution controls. The older mechanical diesels in smaller sizes (275-300 hp) and the lighter rigs on the mid-late 90's did better and do indeed consistently turn in those kind of numbers.

I can get 8-8.5 mpg with my 2004 Cummins ISL in a 40 foot, 37,000+ lb coach & toad, but only at 62-64 mph and steady cruising on an interstate. Anything else, higher or lower, and it drops to 7.2-7.6 mpg. Even larger and newer rigs are likely to be in the 6.0-7.0 range.
 
There are literally dozens of previous conversation threads on this topic.  If you want to read lots of debate on the two styles, click the "Search" button above, type "diesel vs. gas", and then enjoy!  :)
 
yeowch.... I do not remember the years of the coaches people had that I talked to...... didn't realize their mpg was that low on the newer ones......
 
RV Roamer said:
No late model "big DP" is going to get that kind of mpg (though maybe it depends on what you call 'big") and speed is still a factor.  The newer diesel engines get poorer mileage, due mostly to pollution controls. The older mechanical diesels in smaller sizes (275-300 hp) and the lighter rigs on the mid-late 90's did better and do indeed consistently turn in those kind of numbers.

I can get 8-8.5 mpg with my 2004 Cummins ISL in a 40 foot, 37,000+ lb coach & toad, but only at 62-64 mph and steady cruising on an interstate. Anything else, higher or lower, and it drops to 7.2-7.6 mpg. Even larger and newer rigs are likely to be in the 6.0-7.0 range.
Click to expand...

My 2006 39' Fleetwood Providence, with 350 horsepower routinely got between 8 and 9 miles per gallon.
 
2KViggen said:
didn't realize their mpg was that low on the newer ones......
Click to expand...

A bit of news for you: expect the mpg to be that "low" on ANY motorhome you shop for.  ;)  Many times lower.  My gasser averages 7.5mpg, sometimes as low as 6.5 and once I saw it over 10.  ONE TIME.  I still wonder if I did that math wrong that time.  :)

None of us are involved in the RV lifestyle for the fuel economy, so it's one of those things you just have to accept if you are looking at big rigs.
 
scottydl said:
A bit of news for you: expect the mpg to be that "low" on ANY motorhome you shop for.  ;)  Many times lower.  My gasser averages 7.5mpg, sometimes as low as 6.5 and once I saw it over 10.  ONE TIME.  I still wonder if I did that math wrong that time.  :)

None of us are involved in the RV lifestyle for the fuel economy, so it's one of those things you just have to accept if you are looking at big rigs.
Click to expand...

During my last trip of a couple of thousand miles, mine (see below this message) averaged just above 9 MPG and got just over ten a couple of times. Less than 9 only once (8.5).  Much better than I expected.  But my RV isn't all that large and I wasn't in a hurry. Four speed auto tranny.

This RV gets better MPG than the old 1984 GMC 3/4 ton Class B van I onced owned with a 350 CID.

My old  1978 Class C RV (too feet shorter) was lucky to get 7 on the freeway, but it was an old three speed auto tranny. Revved high on the freeways.  But even it got 10 MPH if at less than 45 MPH all day, such as a drive through Yellowstone. It too, only got the ten MPG that one time, but I don't think I made a mistake on the math. ;D

-Don- SF, CA​
 
scottydl said:
A bit of news for you: expect the mpg to be that "low" on ANY motorhome you shop for.  ;)  Many times lower.  My gasser averages 7.5mpg, sometimes as low as 6.5 and once I saw it over 10.  ONE TIME.  I still wonder if I did that math wrong that time.  :)

None of us are involved in the RV lifestyle for the fuel economy, so it's one of those things you just have to accept if you are looking at big rigs.
Click to expand...

very true however when I plan a trip gas prices do come into the equation on how far I can go but it was not a deciding factor for the coach I purchased.  There is no way I could of afforded my 5,000 mile trip this summer if gas was $5.00 a gallon but at $2.20-2.80 we could afford the 3-4week trip out west
 
Thanks for the help guys. I think I have narrowed it down to two. Both are late 90's. One with the 300cummins and other w/ a 330 cummins...
 
If you like the two equally well, take the larger engine.  The more horsepower, the better!

ArdraF
 
Drove my 94 Country Coach Affinity back from Indiana a month ago, 1,000 miles, got 9.5 mpg on 350 HP Cat, averaging 65 - 75 mph the whole way
 
1999 34' ISB 5.9L 275 HP with Banks Powerpack that will give over 33 lb of boost to the turbo.
Gross weight with toad 26,170 lb.
Average MPG 10.215 over 42,827 miles

Last summer slowed down to 55-58 MPH average 10.781 MPG

Every drop of fuel put in it is on a spreadsheet.
 
kevin03278 said:
Drove my 94 Country Coach Affinity back from Indiana a month ago, 1,000 miles, got 9.5 mpg on 350 HP Cat, averaging 65 - 75 mph the whole way
Click to expand...

Kevin03278:

Tailwind all the way? ;D
 
I guess a tailwind ;D mine(350cat) ain't even close to that (we get6-6.5) running around 70-75. but there is a big difference between that and averging? 65-75 I guess
 
kevin said:
I guess a tailwind ;D mine(350cat) ain't even close to that (we get6-6.5) running around 70-75. but there is a big difference between that and averging? 65-75 I guess
Click to expand...

Sorry Kevin, got my Kevins mixed up. ;D  I'll correct the other post.
 
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