DP vs Gas on Pulling

RVUSA wrote:

psw757 wrote:
on the gas I averaged just about 6.6 mpg

Thats pretty low. I would get 9 - 10 mpg's on my 38.5' v10 pulling a 4000 lb toad.

Probably different years of the V10. The Newest version puts out a lot more power with the same displacement so should be more efficient. You're 9-10 with toad is definitely on the highest end I have ever heard though. I usually get about 7mpg with a combination of flat Florida and "hilly" Florida.

Medico wrote:
The other problem, which has been mentioned briefly a couple of times, is that a gas motor will have to rev much higher to get up that same hill as a DP. That is one reason why oil change intervals are more frequent with gas engines. They have to work harder to accomplish the same thing. Generally this is not a problem if you do good maintenance and the gas engine has lower miles. That same gas engine, as the miles begin to accumulate might need major work much sooner than a diesel engine.
In addition, as has been mentioned, most gas chassis start out much shorter and need to be extended to accommodate larger coaches. The chassis/gas combo was designed and rated for the shorter chassis. Put a longer chassis on it without changing something else (gear ratio for example) and you will shorten the lifespan of the chassis, including the engine.

Medico, I'm a fanboy of diesels but I don't agree with most of that statement. The V-10 is made to work, there are folks over on the class c forum who use this engine for work purposes and have over 500000 miles without significant problems. The e-450 and the f53 chassis are very well designed and are really workhorses for the gas side.

No they won't handle a 60000 lb Coach. But I can tell you that over the lifeccyle of a typical v-10 versus a venerable Cummins (which I love), the v-10 will be cheaper to operate hands down. None of that means I don't like diesel power, I do! And I will switch to a diesel pusher in the next few years because of air ride and comfort as I retire.

Most of the frame design issues have been put to rest over the years and the new Class C's are very capable, Forest River now has a 7500 lb hitch rating.

In my opinion it's a complicated choice, layout , comfort, price point you can be comfortable with, and then drivetrain selection knowing diesel will cost more not just for the fuel itself but on odds for long term maintenance.

RVUSA wrote:

psw757 wrote:
on the gas I averaged just about 6.6 mpg

Thats pretty low. I would get 9 - 10 mpg's on my 38.5' v10 pulling a 4000 lb toad.

Our was a class c coach so there are a few other variables and the 4600lb toad had us fairly close to max weights.

How much does your coach weigh?

psw757 wrote:
on the gas I averaged just about 6.6 mpg

Thats pretty low. I would get 9 - 10 mpg's on my 38.5' v10 pulling a 4000 lb toad.

All this talk of who is the fastest to the top of mt Everest cracks me up!

I know for a fact as I just made the switch from a ford v-10 coach to a 300 cummins diesel that the diesel is just simply smoother and more efficient than the gas.

Yes the gas is a very capable engine but something I can't ignore is the fact the both were pulling a 4600lb jeep for the last 3-4 years and on the gas I averaged just about 6.6 mpg and with the diesel so far 11.8. Huge difference! Yes I hand calculate and keep logs. This is also traveling mainly up and down the relatively flat east coast. We couldn't even make a round trip from Philadelphia to the finger lakes of ny with those small hills on one tank of gas. Just under 300 miles on a 55 gallon tank, not good!

My gasser weighed around 20k gcwr and the diesel just weighed in at a hair below 28k gcwr.

If you read Johnny T FAQ's and go to Choosing Diesel vs Gas he explains it very well in detail with charts and other ref materials, as does Silverback. To further simplify your question, I have never seen a DP and a gas class A that were the same weight. Typically a 38-40 ft DP will weigh over 30k lbs. In gross terms a short gas will weigh half that. 300 hp divided by 30,000 lbs is .01 HP/WT ratio. A 32 ft Class gas A would weigh maybe 18,000 lbs and with 362 hp would have a ratio of .02 and would be much faster than the DP up the hill or on the flat road. Compare 0-60 or 40-60 mph times often posted in MH reviews in MH magazines, that will tell you which will be faster for hill climbing. The choice would have to be based on ride quality, noise level, exhaust brake, higher quality build etc. not power. I have a 18 year old 454 class A with headers etc. that has maybe 300 hp and can out climb my 3 friends DP's because of the above reasons.

The other problem, which has been mentioned briefly a couple of times, is that a gas motor will have to rev much higher to get up that same hill as a DP. That is one reason why oil change intervals are more frequent with gas engines. They have to work harder to accomplish the same thing. Generally this is not a problem if you do good maintenance and the gas engine has lower miles. That same gas engine, as the miles begin to accumulate might need major work much sooner than a diesel engine.
In addition, as has been mentioned, most gas chassis start out much shorter and need to be extended to accommodate larger coaches. The chassis/gas combo was designed and rated for the shorter chassis. Put a longer chassis on it without changing something else (gear ratio for example) and you will shorten the lifespan of the chassis, including the engine.

Another way to fairly evaluate this is the weight of the Coach/ torque. So, mine weighs with my toad, 19000 lbs. 19000/426=44.6 lb per ft-lb torque. My buddies Coach 60000/1250=48 lb per ft lb torque. I think that means the rigs are very similar in the power department.

Not in price of course! His American Heritage would cost 7 or 8 times as much as my Class C. It's a powerful smooth running machine and I hope to own one one day.. But it is much more expensive to maintain. A set of injectors costs more than a new v10.

Not some might say, Mike you left our the final drive ratio and transmission interplay on the Coach performance and I did. But if you are innovative, you can develop a curve using the above for each gear of the respective transmission and compare the two. Ford has done a great job marrying the V10 to just the right transmission. And Cummins has too. It's cool to study it. But the gearing is a big big deal and the newer models have a lot of technology in the Coach's.

The v10 is made to and likes to rev. It's no problem for it to run at 4500 rpm for all of its life but it will suck the gas.

I had no problem following my friend to Colorado this last summer.

But I don't have air ride suspension and all the amenities. It really comes down to what you are using the Coach for and what you want to spend.

I debate the issue myself. Will I really like the bigger more expensive machine over the long haul? Or will I really just like the flexibility of getting into any campground with my Class C.

I don't know the answer. I expect I will spend money to figure it out. Lol

Well said PastorCharlie main reason I own gas. Less cost to purchase, less cost to maintain. This from someone with a 675,000 mile 99 Ford Diesel truck carrying the biggest Lance camper made in 99.

Unless one is constantly on the road the engines do not matter at all; parked in a campground there is no difference between a 10 hp and a 600 hp except the dead weight and the cost of the engines. There the house on those chassis is what is important.