mpg of new gas motorhomes

[cosmic]

So i have mentioned in the past that I had a buddy who worked at a big RV dealership 6 year ago and would drive different rigs from one dealer to another and one RV show to another, sometimes 250 miles away.
He would say to me that i should not kid myself that the new ones  get any better milage then my old 440.
He said the v10 was worse. now keeping in mind weight and aerodynamics, are the new rigs getting much more?

What do you think a 24 foot 2008 gets for milage? much better then our old 70's with a properly tuned carb?
I mean we know its better but how much better?

any of you long road trip guys have buddies you do long trips with, that have newer rigs (gas) who have to fill up along the way and cant lie that there making 15 mpg. what are they really making?

just love to here whats the real truth on milage of newer rigs?

[Lefty]

I know somebody with a 32' Class A on the Ford V-10 powered chassis... they get between 6 and 8mpg...no better than the old Winnie's..but is a bit larger.I have some friends who have a 40' Holiday Rambler that's a diesel pusher... they get 10-12mpg.

[Wantawinnie]

It's not "new" but my dad's 1996 32' Winnebago Itasca has a fuel injected 460 Ford with overdrive. I drove it on a 3000 mile trip to Florida and averaged a little better than 7mpg on the trip. I was mostly travelling interstate speeds of 60-65mph the entire trip.

[bluebird]

If you guys think that a modern fuel injected rigs don't do better, your fooling yourself. My 1980 Itasca 26 fter pulling my race car and trailer got 4 to 6 mpg, with a properly tuned 454/ 400 turbo. My 95 Damon Challenger with a injected 454/ 4l80e trans does 10 mpg average. On a real windy day she'll do a little worse. Last year on one of my trips down to Tenn., running 65/70 without the genny running I averaged 11.8, running the engine air. I really think my old winney was heavier than the challenger, and it's 4 ft longer. I'll tell ya one thing, longer wheel base and 19.5 tires sure makes a big difference in handling. My Itasca had 4.56 gears and the Challenger has 5.38, with  the lower gears in the 4l80e trans it pulls the race car with ease, and in OD. I don't have a tach in it but it doesn't take much throttle to run 65 mph.

[cosmic]

So Bluebird.

Would it be fair to say that your better milage could be from your overdrive transmission and gearing as well as you believe the newer rig to be lighter?

Or would you say it has more to do with the fuel injection (as i don't think the 454 platform changed all that much)

As i said earlier to everyone. we know its better but how much better. (bluebird says double better milage)

Others say 6 to 8 mpg same as the old ones.

more testimony needed here!!!!!!!

[LJ-TJ]

Well there seems to be a bracket of 5 to 10 miles to a gallon with the old rigs. Sure there are those who claim to get 10 and up to 15 but I believe them to be the rare exception usually at midnight down hill with a tailwind. But for Newbees trying to decide weather or not to buy one of these rigs based of mileage, plan on getting 5 to 10 miles to the gallon.My personal experience is with both a 1975 21' Brave. One with a 318 and currently one with a 440 in both cases depending on road conditions and driving technique I average between 5 to 10 even with the 440. The 440 makes all the difference in the world in that it's easier to get the rig rolling and once rolling it seems effortless to keep her at speed and great for going up hills.

[cosmic]

For my 1975 d21 440 i can say that 6 to 8 is the norm. 6 if im in a rush and 8 if i take my time. Thats on an average day. not to windy, and flat roads to the most part.

I once posted that I got 10mpg. I was drinking that day and it turned into a fishing story. LOL.

So back to the newer rigs.....  no fishing stories. LOL

[ClydesdaleKevin]

A friend of ours bought a brand new Damon with a Ford 460 in it.  Its 32 feet long or so.  Fuel injected.  When he got it right off the lot it was only getting 5mpg!  After extensive tuning work including a brand new Banks header system...the whole shebang...he's still only getting 6mpg, and that's on a good day. 

I'm thinking gearing and overdrives and whatnot would have a much more significant impact on gas mileage on a big block gasoline engine...only so efficient a gasoline engine can be, no matter what kind of exhaust you have or how well tuned.  Driving habits probably effect our friend's mileage quite a bit as well, since he tools down the highways at 70mph.

Kev

[Wantawinnie]

The Ford F53 chassis under my dad's 1996 Itasca is setup with smaller 16" wheel/tire combo and deeper rear end gears. I don't really care for it and overdrive rpm on the highway was only slightly lower than my '73 Winnebago. I can tell you that the best it has ever done was 8mpg between fillups, average over the trip was closer to 7mpg. Even if the fuel injection doesn't help with mileage it still makes for a nice smooth running engine.   

 

[Oz]

Let's keep in mind that the subject question cited 2008 as an example.

Rather than, what mileage a 1996 gets or what mileage a diesel motor RV gets...

... I would reasonably assume what we are looking for is info on gas mileage for motor homes from like 2005(?) and newer so, if you've got accurate info on this, please post it!

[ClydesdaleKevin]

Yep.  My buddy's Damon Intruder is a 2011...and he gets 6 mpg driving highway speeds of 70 or so.  Gasoline engine, Ford 460, fuel injected, Banks system, the whole nine yards.  And he tows a little Saturn with not much weight in his compartments.  Its got power...he can go up the mountains at highway speed limits...but it doesn't have any better fuel economy than our old rigs.

Kev

[bluebird]

Well I don't know anybody that has a NEWER motor home then. And I don't think there will be anyone with one lurking on a Classic site to get you the info you desire. I do have several friends at the track with mid 90s and early 2000s. Some of the larger coach's with Ford power don't do real good, but still gets better than my old Itasca.

Cosmic, I think it is the total package that made the improvement. I do know the injected engines run much smoother, and with the computer constantly adjusting has to help mpg. I also know guys that only get 8 to 10 but don't know their driving habits. I drive mine the same as my Itasca, and wouldn't change even if it got 5. I didn't buy them for mpg.

I sure wouldn't drive 50 mph just to get a little better mpg. If it's hot I run the genny, don't care. I bought this rig to be comfortable when racing or camping.

[tmsnyder]

Oz, is there an appropriate place to post mpg's for 'old' rvs?

[BrianB]

There is some good "New RV" gas mileage information on this blog post: http://www.gonewiththewynns.com/bounder-gas-rv-fuel-economy-mpg


Be sure to read through the comments. As you can see, modern gas RVs aren't any better than our older units.

[Oz]

Oz, is there an appropriate place to post mpg's for 'old' rvs?

Yes, on each of the chassis boards is a topic for each specific engine.  I.e. Dodge - 440, 318 -  Chevy 454, 350.
Just look at the FAQs and they're on the list.

[udidwht]

Renton, Wa. - Sedona, Az

Total miles - 3099 (US) miles

Total days - 18 (Dec 21, 2020 - Jan 7, 2021)

Total oil consumed - ~ 1/2qt (454 TBI 7.4L w/4L80E) 1994 Fleetwood Southwind Storm 28ft (using Valvoline full synthetic 10w-30)

Total fuel cost - $1008.XX

Odometer on RV currently - 68,295

MPG - low of 7.77mpg and a high of 9.70mpg

High MPG was between Livermore, Ca. and Bakersfield, Ca. On the overall trip I hit the 9.XX range (3) times. After Sedona, Az. I headed south and skirted Phoenix then onto Huntington Beach, Ca. (real home). There for a few days then headed north back to Renton (home away from real home).

The only issue I had was I started hearing a clank up front (on rough road) near drivers side. Crawled under and noticed that one of the sway bar bushings was missing. Bought (2) and replaced both the outer front ones. The other crumbled in my hand into (3) pieces upon removing. 20 min fix.

[tmsnyder]

A friend of ours bought a brand new Damon with a Ford 460 in it.  Its 32 feet long or so.  Fuel injected.  When he got it right off the lot it was only getting 5mpg!  After extensive tuning work including a brand new Banks header system...the whole shebang...he's still only getting 6mpg, and that's on a good day. 

I'm thinking gearing and overdrives and whatnot would have a much more significant impact on gas mileage on a big block gasoline engine...only so efficient a gasoline engine can be, no matter what kind of exhaust you have or how well tuned.  Driving habits probably effect our friend's mileage quite a bit as well, since he tools down the highways at 70mph.

Kev

They quit making the 460 in 1998 btw, I guess it was brand new then?

[tmsnyder]

Here's two 'old' motorhomes mpg data. 

1976 GMC Motorhome, 26', 455 BB Olds, TH425 (no overdrive):  4,000 miles logged, average mpg:  8.80 after 2% odometer correction
https://www.fuelly.com/car/gmc/tze/1976/tmsnyder/963498

1989 Chevy P30 chassis 1990 Holiday Rambler AlumaLite XL 31' 454 BBC, TH400 (no overdrive):  19,000 miles logged, average mpg: 7.4
https://www.fuelly.com/car/chevrolet/p30/1990/tmsnyder/454843

So you can see mileage is actually trending _downward_ with newer rigs!  LOL

My brother has a 2005 E350 Class C, 25 feet long, V10 with OD and he got about 9 on a recent long trip. 

But as you can tell from the above, I don't trust anyone's mpg claims unless they have a fuelly account and have logged their actual miles and gallons for at least 1000 miles.  If you look at the tank to tank variability, you can see it's easy to get a single apparent high mpg value.  To get actual accurate mpg you need to log every drop, and every mile for 1000s of miles.   You can't get the mpg from a single tank of fuel, not with any confidence.

[tmsnyder]

In terms of mpg data for modern motorhomes:

Here's some data for 2015 Winnebago Forza motorhomes. These are 34' diesel pushers and they are getting 9-14 mpg:   https://www.fuelly.com/car/winnebago/forza/2015
Diesels generally get 30% better fuel mileage than gasoline, so the same motorhome in gas would be around 7-11 mpg.

Here's a 2014 25' Sprinter based Winnebago VIA, he's only getting 6.1mpg and that's diesel!:  https://www.fuelly.com/car/winnebago/via_25p/2014/newmar/913178
This seems to be an outlier though b/c other 2019 diesel sprinter RV's are getting 14-16mpg:  https://www.fuelly.com/car/winnebago/navion
These small Class C Sprinter vans do seem to get pretty good fuel mileage.  You should get 14-16 but then you're stuck in a small Class C and the buy-in cost is high.

I don't think this is b/c it's a modern motorhome though, I think it's b/c of the smaller frontal area.  I've read that 1970's GMC motorhomes repowered with a 6.5L diesel get 14-15mpg.   And so does a 70s FMC motorhome repowered with a Duramax/allison OD combo.  These are small frontal area motorhomes but they are 26 and 29 feet long.  I don't have any actual mpg data though, just word of mouth.

These 2002-2004 Chevy Gas with OD Workhorse based Class A's are only getting 7-8 mpg based on over 30,000 miles of data:  https://www.fuelly.com/car/workhorse/p30

If you get an older, vintage motorhome and properly maintain it; clean the carb, give the engine a tune-up, make sure the timing is right; you should get similar mpg as a new IF you keep it below 60mpg.

I've read that installing a efi system should get you a little more mpg possibly, but the payback time is going to be extremely long;  not worth the investment.   

So long answer short;  No.  Fuel mileage hasn't improved significantly

[Schmitti]

As you know, I sold our beautiful '76 Chieftain four years ago . Since then we've been driving a Thor Hurricane from 2000. This has a maximum weight of 6.8 tons and a 454 Chevy V8. We manage about 9.4mpg on gasoline, but that is almost impossible to pay in Europe, as a liter of gasoline costs 1.45 €. That is why we drive with Liquid Petrolium Gas. Here the Chevy needs 7.84mpg, but the liter of LPG costs only 0.64 cents

Greetings from Germany
Thomas

[Oz]

Good info, Thomas.  Helps us in the US realize how good we have it.

[tmsnyder]

Thomas are your gallons US or Imperial?

A US gallon is 3.78 L

[Schmitti]

I've been in this beautiful US forum too long for that, knowing the difference. Accordingly, of course, I used the US gallon for the conversion.
Something off topic ... The gasoline prices in Germany have been raised to 1.60 € / liter precisely because of the "great" CO² tax. How much does gasoline currently cost on average in the United States?

Thomas

[tmsnyder]

My brother is near Albany NY and tells me that it has hit $3.00 per gallon there.  A recent trip to Florida from NY in my motorhome and I saw prices from $2.60 to $2.90

In Liters that's around $0.79 / L

People in the US really start to complain if it goes above $3!

I believe just across the border in Canada it is well over $1 a L , maybe $1.50?

[Elandan2]

Here in Niagara Falls Ontario gas is running about $1.20/ litre CDN. Unless it's Friday. LOL