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-   -   What's too big for gas. (https://www.irv2.com/forums/f59/whats-too-big-for-gas-489154.html)

GCSuper 05-21-2020 04:45 PM

Two years ago we bought a new 38 ft gas Motor home. Great floor plan for us and we love it. It truly has plenty of power with the way it's geared, but......that power is delivered at a fairly high rpm and going down can be worse. Handling wasn't too bad unless it was very windy and rough roads were just unpleasant. Any one of these by themselves wouldn't be too bad, but combined were enough to make us trade up to a DP. Most of these issues are present regardless of the size. It's just the nature of the beast. Our decision to trade was due to wanting to travel extensively over the next 5 years and we just didn't want to do that in a gas coach. The towing limit was a factor as well.

RI Expat 05-21-2020 06:16 PM

I love my rig, but the mileage sucks and the engine screams at higher speeds under load. I tow a 3400 lb car and have a 900 lb bike in the garage and it marches down the road just fine. No handling issues. But this is probably the max size and weight for a gasser.

AZ RV'r 05-21-2020 06:18 PM

You can see in my signature below I have RV'ed and stayed in all of the lower 48, and been into Canada twice.

Here are some facts and background for my opinion...

My current gas coach, a 2019 Fleetwood Southwind 37F is 38' 9"... just 15" shy of 40 feet long. It has a GCWR of 30,000 lbs and a hitch rating of 800 tongue / 8000 lb. hitch rating. Six speed transmission with a computer controlled top speed of 75 mph. It rides on the 22" Alcola wheels and it's ride quality is far better than my previous two coaches I describe below. It does have a long overhang behind the back wheels but I feel little to nothing when passing semi's or gusty days. It comes with a LONG full wall slide on the DS, and a smaller bedroom slide the PS. Currently its at 16,200 miles, purchased brand new in August of 2018.

My last coach was a 2016 Fleetwood Bounder at 35' 4" long, it was on the 22K chassis and the 5 speed transmission. Towing of 500 / 5000. It rode on the 22" Alcola wheels also. We traded it at 36,000 miles and it was also purchased brand new in 2015. The Bounder was a good coach. No major repairs in the 3 years of owning and it all worked like it should. Anyone that has a good amount of seat time with a 5 speed and then transitions into the newer 6 speed is telling the truth, when they say its a "night and day" difference.

Last... the coach before the Bounder was a 2007 Monaco diesel that had a Cummins 300 hp and was 37' long and we did about 10,00 total miles and we purchased it used. Im not sure about a lot of the specs on this coach as I owned it when I knew very little about rv's. We did NOT like or enjoy our diesel in the 11 months that we had it. Multiple problems...$4500 turbo replacement and about $2000 in other repairs...but just generally a poor quality coach. It probably had the cheaper roadmamaster chassis and only 4 airbags. When we would drive over a bridge, the coach would porpoise 3-4 times, and sometimes we felt like the front would actually bounce over foot or more.... every bridge... every time. Not to mention that every time it crashed down it felt like the front might break the front in half. The engine was too small for the length and weight of the coach and it always felt like it was struggling with or without the Jeep in tow. The weak engine and ride quality was probably 90% of why we got rid of it.

All three RV's towed a variation of the 4-door Jeep Wrangler.

So here is my opinion.... My current coach is the best in all comparisons, even though it is the longest of the three and even when compared to a similar sized coach with a 300HP diesel engine and here is my reasoning for saying that.

I feel if I lined all three coaches up and left from a dead stop, the Southwind would be the quickest from 0-60 and also a rolling start from say 45 up to 70 mph, the Southwind feels like it would definitely be the fastest. Running up a hill I think they would all kinda stink but the Monaco was severely underpowered and heavier. I remember I was always around 35 mph with the hazards on. The Bounder with the 5 speed, although slightly shorter and lighter would be no match for the Southwind with the 6 speed. I believe that the 6 speed is so good it more than makes up for the extra weight and 3 feet of length when compared to the smaller Bounder.

In my opinion after 16,200 miles of driving this coach, my gas surpasses my previous diesel in every way and is not underpowered even at near 40 ft. long. Im not sure, but it's probably close to the longest gas coach available and I believe the power is adequate.

Lastly... yes I do wish it was 600 HP and 1200 TRQ, but.. it is what it is... and it works good enough.

Hope this helps, good luck!

UFO Pilot 05-21-2020 10:26 PM

My gasser is 39', 26,000 lbs and 4,000 towing for a total of 30,000 lbs. It does all I want it to do.

Gary RVRoamer 05-22-2020 08:52 AM

It's not really the engine that makes the difference. It's the overall capability of the chassis to handle the length and weight. Diesel power and the transmissions designed to work with diesel engines show greater advantages as weight and size increases, so heavier duty chassis are near-always diesel powered as well. Along with that you get air suspension and brakes, heftier axles, steering with a high wheel cut angle, etc. All of that combines to make a more robust chassis. A gas-powered heavy duty chassis could be built, but most buyers would also choose the heavy duty diesel engine to go with it.


Ford is building a good front gas-engine motorhome chassis designed to handle coaches up to about 26,000 lbs, which will accommodate coaches up to about 36-38 ft. I'd rather have a diesel-pusher chassis in that range so I could get the aforementioned engineering advantages, but the gas chassis rig will work decently.


By todays standards, a 36-38 ft coach that weighs less than 26,000 lbs would be considered lightly built. Most 36 ft gas-chassis coaches are right up against the 26,000 lb GVWR of the latest Ford gas chassis, so a larger coach would either need a diesel chassis or would have to be slimmed down (lighter construction and fewer features) to fit.

MRUSA14 05-22-2020 09:03 AM

Quote:

Originally Posted by A32Deuce (Post 5272370)
10 speed keeps the engine in the sweet spot of the torque curve!

Yes, except that the sweet spot for torque on most gas engines is around 3000-4000 RPM, whereas in diesels it is around 1500 RPM. Which makes for a much more pleasant drive in the diesel.

A32Deuce 05-22-2020 09:46 AM

Quote:

Originally Posted by MRUSA14 (Post 5273329)
Yes, except that the sweet spot for torque on most gas engines is around 3000-4000 RPM, whereas in diesels it is around 1500 RPM. Which makes for a much more pleasant drive in the diesel.

This engine was based on working and the torque curve is fairly flat and not the 3-4000 range you say. Check it out!

TomsMaHauL 05-22-2020 12:27 PM

After 3 trailers, we went with a Fleetwood diesel pusher. We had it for 6 years. Loved it! We now own a Tiffin 37ft gasser (first brand new purchase in '16), and have, thoroughly, enjoyed it. The only time that we've ever had an issue with this gasser in windy conditions, was when there was a 60+mph wind (and crazy dust storm) as we passed through Amarillo. It was time to pull into a local rv park, and stay awhile. Otherwise, no issues with wind, or passing trucks. The front engine noise isn't loud at all. The optional Sumo springs came with this rig. Otherwise, I haven't added any after-market pieces. I haven't driven gassers from other manufacturers, but I've driven 18k miles in this motorhome, and this manufacturer did a great job on the build. I've had great experiences with the manufacturer, and local dealership service, during the time that I've owned this motorhome.

HighDesert 05-22-2020 01:25 PM

The older gas coaches are screamers when pulling grades. The newer coaches are much better and quieter. Probably oa combination of 6 speed and better build. Our 35' Tiffin, with the V10 does a very good job for us. Pulls the passes good towing a JKS Sahara. I'm happy with it and looked at both gas and diesel when we purchased new last year.

TomsMaHauL 05-23-2020 12:37 PM

I agree with HighDesert.
We went from Louisiana to Williams (Az), the Grand Canyon and back home, with no issues. I had to join the 18 wheelers in the right (slow) lane on some stretches of I40 between Amarillo & Flagstaff, but it was smooth sailin' with no issues. I'm never in a hurry. The V10 is the first Ford powerplant that I've ever owned, and I've been highly impressed with it. We're 240ft above sea level here in N. Louisiana, and we ended up 7,000 feet above sea level during that westward journey. The engine performed very well with the 6 speed transmission (using tow/haul mode the entire time). We learned that unopened potato chip bags swell like basketballs, with extreme elevation changes, and when my wife went to use the hand lotion container, the stuff exploded out of the nozzle.

Urban Hermit 05-23-2020 05:10 PM

1999 F53, V10, five-speed (? I think--maybe four -- how quickly I forget) Itasca Sunflyer 34. Feels like it'll run off and leave our just-acquired 2006 Cummins 5.9 rail with 5-speed Allison in a Monaco Cayman 36, but I may be being fooled by the so-much-quieter and heavier coach seeming to move slower than it does. That's on flat road. I haven't formed an opinion yet about hills but I think the Monaco holds speed better. I've only driven it 750 highway miles bringing it home five weeks ago; it's been in three shops since. But: if you can afford it and you're going over, say, 32, I'd recommend a diesel pusher for the quiet. The other is my first experience with a V10, which sounds like a V8 turning 25% faster than it is -- 2500 sounds like 3100 -- and makes me nervous. Much more relaxed and therefore safer in the diesel.

POPPASMURF 05-23-2020 06:08 PM

Almost all gas engines used in MH chassis have been transplanted from pickup trucks, similarly the transmissions that go with them. In no case have any of the big 3 offered an industrial quality gas engine. They were not primarily designed to haul 20plus lbs without compromise. For the most part the transmissions are the same as they offered in their pickup lines, the engines as well. The biggest saving grace is that we don't pile on the miles in our RV's to obliterate the reliability. With the big block diesels, the engine, the transmissions, and the rest of the running gear are designed and built to push around the kind of weight we overload our RV's with. I too have owned many gas powered and diesel powered MH. The one thing i can say for certain, there is a huge disparity in the kind of power gas engines offered make, compared to very similar engines designed for heavy truck applications. The torque produced by the old 427 truck engine as used in tandem axle dump trucks is far superior to that provided by the common 454 from light truck lineage.

twinboat 05-23-2020 06:08 PM

Quote:

Originally Posted by A32Deuce (Post 5272370)
10 speed keeps the engine in the sweet spot of the torque curve!

And diesels don't have sweet spots ?

10 gears is a gas saving gimic for lightly loaded vehicles. Load them up and you'll never see all 10.

A32Deuce 05-23-2020 06:35 PM

I only know what I read about the new Ford V8. I never said anything about oil burners, just the new gas engine and how it is set up from Ford. I could care less about oil burners, drove them go 37 years.


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