Old RV gas mileage

I used to own a Revcon Prince that had the Front wheel drive like the GMC motor homes. It was 32' long and had the axles in the back like the GMC. With the 454 and headers and Crower cam and Edelbroc manifold it would get 9-9.5 mpg with dash AC and doing 65-70. Made like an Airstream with fiberglass front and sides by the wheels. Special made and designed by the Grandson of the Airstream inventor. We lived in ours for months while our house was being rebuilt after a water line broke while on vacation. It was really nice.

Interesting.....What transaxle did it have? I've never seen a TH425 with a 90° Chevrolet bellhousing bolt pattern before......BOPC only.
 
Im a little high on that, but not much - closer to 1 GPH to run 2 -15KBTU AC units.

Onan 7000 will drink about 1.2 GPH at full tilt when new

sometimes you can run 1 at night but on an 80-90 degree day you'll need 2 plus the dash air.

but to your point - yeah its expensive.
Our 4k uses .5 GPH to run the AC.. depending on how much the AC runs can be less. We ran the AC and generator in New Orleans few years back 8-9hrs and can't recall exacts but didn't use more than 4 gallons. And that AC ran.. look like a lake around with the AC runoff.

To answer OP's question you don't buy a RV for the mileage LOL .. back when gas was cheap 4-5mpg isn't anything at less than .99. Our 6.0L ranges between 8-10mpg. But we easily save that not eating out every meal.
 
That Revcon had a th750 as I recall with Kevlar lined bands and a FWD tranfer case on the end with a driveshaft forward to the differntial. It was all built on a frame and was bolted to the chassis. You could remove those 5 or 6 bolts and jack up the body and roll the whole drive train out to repair it. It was a very unique designed animal. It had enough guts to leave most cars at a stoplight. When I sold it, I would take the lookers for a ride. Several were plain scared buy its power. It also had Weld Racing wheels on it. I had it for about 5 years but ran out of parking space.
 
Yep, like said above, I've known people with similar and you'd be looking at around 5mpg at best.
 
I had a 2000 Winnebago 38ft with V-10 Ford engine, 4 sp trans, 5:13 rear gears. Would get 6-9mpg on interstate depending on wind. I will say the 9mpg was pretty rare, like no wind or slight tailwind. 75 gal gas tank. I always drove close to posted speed limit in it. It was always downshifting and cranking out high rpm. Was cool for the first 50 miles, then my ears got sick of the engine noise.

BTW my 2018 F150 3.5L ecoboost towing a lightweight (5000lbs) 30ft trailer got 8mpg. But was alot quieter.
 
Once you are under 12mpg.
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Our 4k uses .5 GPH to run the AC.. depending on how much the AC runs can be less. We ran the AC and generator in New Orleans few years back 8-9hrs and can't recall exacts but didn't use more than 4 gallons. And that AC ran.. look like a lake around with the AC runoff.

To answer OP's question you don't buy a RV for the mileage LOL .. back when gas was cheap 4-5mpg isn't anything at less than .99. Our 6.0L ranges between 8-10mpg. But we easily save that not eating out every meal.

When you say 4K are you referring to the Onan "Microquiet" 4000 ?

Were you running a single 13.5K BTU or a 15K unit?
 
OP -

when running a genset in an RV you do not have the capacity of the tank to work with but a subset of that.

the genset pickup is usually somewhere around the 1/4 tank mark so on a road trip or dry camp situation you fuel availability is restricted.
 
70? I can’t imagine that box going 70 but it probably could. I got 10 with a 19 foot class C powered by a four barrel 350 Chev, all 1971 vintage. It never went over 60 at cruise to get that. It had tremendous power though, when the extra two barrels were used. Went up grades like not there. If I went 55 on a flat road staying in two barrels, I think it got to 12 mpg. Maybe. TH400 transmission. A number of people wanted to buy it from me, but donated to St Vincent De Paul along with a Rover 3500S in rust free beautiful shape if the same vintage.
So that one it is going to cost money every way you look at it, a lot of money.
 
I have a 19and 1/2 foot Roadtrek Versatille from 1993 on a Dodge 1 ton chassis with a 5.2 Magnum. Gets 16mpg at 70 mph. Can sleep 2 adult and 2 kids. Keep it for trips out west. My 27 ft Coach House with the 6.8 Ford with full Banks Power headers and all can get 14.5 but usually closer to 11-12. at 68mph.
Shenanigans.
 
Yes and a 13.5k Carrier V.
Thats about what I got running a coleman 13.5.

Lots of people had micro quiet 4K problems. I did not. although I wouldn't call it that quiet.

Not my fav small Rv generator though.

I do like the altitude adjustment on the side of the carb.
 
I've managed to get 12 in my XTerra towing a teardrop trailer with a pair of kayaks on the roof. Honestly at that point, an RV doesn't seem much worse...
 
Our 4k uses .5 GPH to run the AC.. depending on how much the AC runs can be less. We ran the AC and generator in New Orleans few years back 8-9hrs and can't recall exacts but didn't use more than 4 gallons. And that AC ran.. look like a lake around with the AC runoff.

To answer OP's question you don't buy a RV for the mileage LOL .. back when gas was cheap 4-5mpg isn't anything at less than .99. Our 6.0L ranges between 8-10mpg. But we easily save that not eating out every meal.

if you want good MPGs buy a vixen RV,
30mpg at 55mph

Everything else on the market save Westfalias and Mercedes Van conversions are very lucky to hit double digits,
my fathers Oshkosh diesel pusher motor coach was good for 10mpg by itself, towing, city or highway as long as it wasn’t too cold or driving too fast but it was a larger rig.


That said the cost of maintenance and repairs will dwarf your fuel budget unless you get a stellar rig and drive high miles.

Just brakes on most RVs can be a PITA on just the part costs alone.

Any stupid simple but proprietary part on an RV like a custom driveshaft that rattles off will blow more $$$ than you expect (especially on Ford conversions)
Drivetrain parts in general are much more expensive to fix and much more likely to die by rust.
 
Ive stayed with bumper pull... would love a small 5er if there was a chance to upgrade. My wife says she’d prefer some sort of coach, but I don’t want another drivetrain to maintain, or rot while it sits- they really don’t like to sit unused. of course, this also means, as I don’t want to commute in a 3/4 ton, that were in 1/2 ton territory which probably caps trailer weight around 6000lbs or so wet, for practical interstate travel. 22-24 is a really nice size. We have a single axle 19 right now - wife loves it - is wish it were a touch larger but for 2 it’s been easy to live with.
 
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