Are large gas motor Rv's underpower?

[invmartyc]

At the risk of getting someone angry for me asking the same question they don't want to see again, that no doubt some people feel has been discussed enough.

Are gas Class A's underpowered to tow a toad in any area with mountains or large hills.

I have read people with gassers say that they are powerful enough for them to tow a toad anywhere. And I have read that no gas motor Class A has the power and that you need a diesel motor.

What is the truth, not opinion on this?

[tatest]

Pounds per horsepower determines acceleration and speed climbing hills. Many A gassers are at 50 pounds/hp or less, the heaviest are just under 100 pounds/hp at full GCWR, rig and heaviest allowable tow.

Small DPs (especially the older ones with 300 hp or less) are often just over 100pounds per HP, and most manufacturers tend to increase power with upgrades in size and weight ratings to stay slightly better than that figure.

Compared to your typical passenger cars and SUVs at 18 to 30 pounds per hp, all RVs are underpowered. Compared to 120,000 pound over the road trucks with 200 pounds per HP, RVs are not particularly underpowered.

People who like diesels like that they generate high torque at low RPM, so they don't need to run at high rpm to get the same power and torque at the drive wheels, which is the place where torque needs to be measured, for comparisons.

[Bumpyroad]

rgatijnet1 wrote:



A lot of progress has been made in 14 years. The newer gas coaches are not near as loud as they were. I have no problem hearing the DW at 65-70 cruise. Maybe I should look for a 2000 model. :B

I had a dreadful noise in the right front of my Chieftain, then I moved her back to the sofa.
bumpy

[rgatijnet1]

tom076 wrote:
I have a 2000 Coachman Triton V-10, power has not been an issue, we are looking at a DP, because of the hope that it will be a quieter ride. We have to shout at each to be heard over the engine. Radio is of no use while traveling at 60-65 MPH on level road, just gets worse on hill climbs.

A lot of progress has been made in 14 years. The newer gas coaches are not near as loud as they were. I have no problem hearing the DW at 65-70 cruise. Maybe I should look for a 2000 model. :B

[tom076]

I have a 2000 Coachman Triton V-10, power has not been an issue, we are looking at a DP, because of the hope that it will be a quieter ride. We have to shout at each to be heard over the engine. Radio is of no use while traveling at 60-65 MPH on level road, just gets worse on hill climbs.

[DanTheRVMan]

rgatijnet1 wrote:
Any coach will get you to point B eventually and once you are enjoying the views, who cares what engine got you there?

Yes

It is about traveling and being there.

[the_silverback]

Getting back to the post, there has been a "rule of thumb" posted on this form several times that if your coach weights less than 100 pounds per horsepower you will be OK. I prefer 90 pounds per HP. My present gas MH and toad are at 83 pounds per HP. 28000 pounds/ 340 HP.

[Daveinet]

I would contend that the longevity of a gas engine mostly has to do with if you run it regularly and maintain it. Biggest problem RV engines have is that they sit for several months in the off season, which allows moister to accumulate, which introduces rust.

A comment a few posts above speaks of mileage comparison. It may have been hyperbole, but there is not that much difference in BTU content between gas and diesel. Its only around 13%. Detonation is a little more efficient, but not enough to double the mileage. I'm pretty sure my engine would do just fine in the place where most diesels are used. Gear ratio would need to be changed to match red line, but it would do the job just fine.

[wa8yxm]

Long Long time ago.. My brother drove a gasser.. A Ford 8,000 Gas Conventional SEMI tractor, pulling a flat, with sides, usually tipping the scale right close to 40 tons (80,000 pounds) (Later in life he upgraded. To a Kenworth, pulling a flat (no sides) loaded with steel, and a 160,000 CGVW plate.

But he drove that Gasser cross country week after week for several years, Delivering to most of the USA. Then picking up stuff coming back toward Detroit,, Lots of power, No problems, just routine service and check the oil.

I can not tell you how many miles he put on it but 100,000 a year would not be far off.

I have seen Gas Cars (Not as many gears means higher RPMs and more engine wear) hit 200 to 300 thousand miles and more. With proper care.

A lot has to do with HOW you drive.. Light turns green, you mash the pedal to the metal, Jet out of there, come up to the next light and stand on the brake,,, Shortens everything life.

Light turns green and you GENTLY press the pedal timing it so you get to the next light just after it gets turns jelous (Green) and the next and the next cruising down the drag without having to mash on the brakes.... Lasts longer

I once drove a stick shift, all the way home from work, without using the clutch.. Several lights,, No problem.. I knew the timing.. Fixed clutch linkage next morning.

[Sully2]

Bumpyroad wrote:

I don't plan on hitting that hill at 30 mph. probably speed up to 60 or more at the base.
bumpy

AMEN...that makes 2 of us

[rgatijnet1]

Mr.Mark wrote:
Rgatijnet1, one thing that I want to point out is anytime there is a comparison of gas and diesel, which is not what the OP was asking, so I know I'm off topic.

There is no way you can put a gas engine in the size motorhome that usually has a diesel engine. Referring to what John S. wrote and your response, a gas pusher would get 4 mpg in the same size motorhome that John S. is getting probably 8 mpg.

As we all know, it's about weight when you start seeing diesel engine's installed. So, in your example, the cost difference of diesel is a wash-out when comparing the fuel mileage of a gasser.

A good example would be the sprinter diesel compared to a similar sized Ford V-10.... 18 mpg vs. 10 mpg.

MM.

You are absolutely right when it comes to overall weight of the coach. He did seem to be inferring that at 163K miles a gas engine coach was near the end of it's life, which I disagreed with. If I did have the fictional gas engine coach, and had put 163K miles on it, compared to his coach, which was granted heavier, longer, etc, I would still be happy with my coach, hence the 163K miles, and be $10,000 ahead. Not everyone wants a longer and heavier RV and are perfectly happy with a shorter lighter gas powered RV. We all still get to see pretty much the same sights as we travel around the country and everyone has different requirements on how we chose to travel. One sizes does not fit all when it comes to RV's. Any coach will get you to point B eventually and once you are enjoying the views, who cares what engine got you there?

[Mr_Mark1]

Rgatijnet1, one thing that I want to point out is anytime there is a comparison of gas and diesel, which is not what the OP was asking, so I know I'm off topic.

There is no way you can put a gas engine in the size motorhome that usually has a diesel engine. Referring to what John S. wrote and your response, a gas pusher would get 4 mpg in the same size motorhome that John S. is getting probably 8 mpg.

As we all know, it's about weight when you start seeing diesel engine's installed. So, in your example, the cost difference of diesel is a wash-out when comparing the fuel mileage of a gasser.

A good example would be the sprinter diesel compared to a similar sized Ford V-10.... 18 mpg vs. 10 mpg.

MM.

[rgatijnet1]

John S. wrote:
I would say the issue is not underpowered but longevity. I just turned 163k on my coach. I am not concerned about the drivetrain. If I had a gasser, I am sure I would be thinking of a new engine or transmission sooner or later. Now some people put a few miles on but the old diesels of the early 90s are still running strong on the original drivetrain. If you are going to travel 5k a yr and keep it under 10 years either works but mine is now 13 years old and I totally remodeled the inside and it is good for another 13 years at least. Friends took a 93 up to Alaska this summer. The other thing people forget when they say floor plan is the deciding factor is how you are going to use it. I have 110 gallons of water and a 110 grey and 80 black tank. I can boondock pretty easy and for a while and my fuel rank is 200 gallons too. Means I can drive across country filling up at the cheapest locations.

It is all relative. If I were you, at the age and mileage on your coach, I would be worried about the radiator going bad, which from reading the numerous posts on this forum about DP radiator problems, can easily cost as much as a rebuilt long block for a gasser.
I also agree that you probably have a longer range but figuring that you pay 50 cents or more a gallon($100/fill-up) the extra fuel cost for your 200 gallon tank, that is not really all that good.
Using your 163,000 miles, at 8 MPG, you spent an extra $10,000 for your fuel then the same gas engine would have spent. That is more than enough for a new gas engine, even tho both the Ford and GM engines were designed for 250,000 miles. There is no doubt that some DP's are superior to some gas powered coaches but the question was whether the gas RV was underpowered, which as many gas owners have stated, they are not.

[John_S_]

I would say the issue is not underpowered but longevity. I just turned 163k on my coach. I am not concerned about the drivetrain. If I had a gasser, I am sure I would be thinking of a new engine or transmission sooner or later. Now some people put a few miles on but the old diesels of the early 90s are still running strong on the original drivetrain. If you are going to travel 5k a yr and keep it under 10 years either works but mine is now 13 years old and I totally remodeled the inside and it is good for another 13 years at least. Friends took a 93 up to Alaska this summer. The other thing people forget when they say floor plan is the deciding factor is how you are going to use it. I have 110 gallons of water and a 110 grey and 80 black tank. I can boondock pretty easy and for a while and my fuel rank is 200 gallons too. Means I can drive across country filling up at the cheapest locations.

[prstlk]

A thought through the fog. Gas engines are less expensive than diesels to produce. It is less expensive to make a gasser then a dp. There are advantages to both. Research based on what you want and it will lead you to your answer. There is help here when you decide.

Never argue with an idiot. ..those watching may not be able to tell the difference

[hanko]

its getting deeper.