DP owners: does dash A/C use effect fuel mileage?

[dezolen]

If you are so worried about fuel consumption don't run genny or dash ac. But then driving at highway speeds with windows open creates more drag and mileage will suffer.
Perhaps you should stay home and save even more.

[jondrew55]

Ok. Maybe I was wrong

[Spinner]

[QUOTE=DMTTRANSPORT;2563082]

Originally Posted by dlaughlin

I sure HATE when people hijack a thread with statements such as "You own a DP, you can afford XYZ!" or something to that effect...

We are under 35 and we worry about pennies and nickels and dimes when we can. That is WHY we can afford to own a 40' DP and enjoy it. Most folks in their mid-30s are buying their first pop-up campers and financing them for 10 years.

For those of you with more money than God who enjoy opining on others' financial situations, let's play pretend... If you were given the option of doing "A" or "B" with the end result being equal (i.e. everyone is comfortable and cool) would you choose the more expensive option just because?

That said, I will always choose to be comfortable no matter the cost. But, the intent of my question is to gauge my expectations on our first trip. I shared my past experience with a gasser and didn't know how the A/C compressor on DP works.[/QUOT

The A/C in our DP works fine after I did an evac & recharge with the right amount of R13...do not notice a difference in mileage, nor do I worry about it, you purchased a nice Coach, Enjoy!!

It will cost you fuel to run A/C. Whether genny or dash is cheaper? Do an experiment. I'm guessing it's different for every vehicle.

I too, was in my 30's when I got the 40'DP. I'm not made of money, but I'm also on vacation when I use it and when I'm uncomfortable I turn on whatever HVAC is required to be comfortable. If I'm comfortable, I will be a safer driver. That's my $0.02 worth.

Remember, on this and the rest of the Internet, the information is worth exactly what you paid for it.

[DJJ]

Originally Posted by DMTTRANSPORT

Some proof that the Hyd Fan takes 60 hp, hear say!, How much hp to move the steering wheel...same hyd pump...

Sorry, but they are different pumps. At least on my Freightliner Dutch Star with a side radiator.


Jeff
2003 Dutch Star, 3126B Cat.

[FIRE UP]

Originally Posted by dlaughlin

I sure HATE when people hijack a thread with statements such as "You own a DP, you can afford XYZ!" or something to that effect...

We are under 35 and we worry about pennies and nickels and dimes when we can. That is WHY we can afford to own a 40' DP and enjoy it. Most folks in their mid-30s are buying their first pop-up campers and financing them for 10 years.

For those of you with more money than God who enjoy opining on others' financial situations, let's play pretend... If you were given the option of doing "A" or "B" with the end result being equal (i.e. everyone is comfortable and cool) would you choose the more expensive option just because?

That said, I will always choose to be comfortable no matter the cost. But, the intent of my question is to gauge my expectations on our first trip. I shared my past experience with a gasser and didn't know how the A/C compressor on DP works.

Dennis,
Apparently you missed my point. No one "Hijacked" the thread. Statements have been made, obviously including mine, that, if ANYONE purchases just about ANY fueled coach, it's going to cost money TO OPERATE IT, PERIOD. That means moving on down the road, with or without A/C or, with or without a TOAD, or any other variance. And that cost, is going to vary, mile by mile, grade-no-grade, foot to the floor or coasting.

Trying to estimate a fuel mileage difference due to the use of A/C in not only a heavy diesel powered coach or, a small 22' Class C, for about 99.9% of the drivers out there, is basically impossible. There's many reasons, hills, slow driving and acceleration conditions (heavy traffic), head winds, actual speed (higher vs lower) and more.

It really has nothing to do with "Cause you own a diesel you can afford XYZ" The point is, and someone already made it on here, if you're going to purchase a 7 mpg vehicle, running A/C is the least of cost worries. Our rig gets 7-7.5-8 about 100% of the time. Knowing that, I figure the total distance on a trip and divide by the lowest, 7 mpg. With that figure, I apply the max amount I might have to pay for fuel for the total trip which, I estimate to be the highest I'll possibly pay, and, when I come up with that, I basically know what I'm going to pay for fuel, on any given trip.

I will run the A/C on some of it, and sometimes I won't. I might be running the A/C on many, many down hill stretches which, means no throttle at all. But, I may be running it on up-hill grades too which, means full throttle. There is no way on this planet, ANYONE can calculate what the cost of running that A/C with so many variables.

There are people out there that say that, running with their headlights on costs more money. Yeah sure it does. Again, there's so many variables in and on a trip, that trying to calculate that kind of miniscule difference, IS IMPOSSIBLE.

So, if you want to save money, I wouldn't worry too much about running the A/C. I'd keep the family as cool and happy as possible and find cheaper camp spots, or, no camp spots at all and stay in Walmarts. The kids won't like that too much but, you'd be saving money.
Scott

[dlaughlin]

Originally Posted by dezolen

If you are so worried about fuel consumption don't run genny or dash ac. But then driving at highway speeds with windows open creates more drag and mileage will suffer.
Perhaps you should stay home and save even more.

Mr. Dezolen - Thank you for your most valuable insight. I NEVER thought about staying home. I will certainly do that from now on. I'm never going anywhere, ever again! Will you next teach me how to become a curmudgeon?

I just don't understand why some folks feel the need to be rude. "...stay home and save more."

The purpose of the question wasn't to be a cheapskate, although I am one. I am not worried about fuel consumption, per se.

I simply wanted to know how the dash A/C compressor is powered. If it truly takes 60 horsepower to power the A/C as some have stated, well, then of course a significant amount of power, thus fuel, is robbed from moving the coach forward. However, if it is 100 degrees outside, all A/Cs will need to be running.

Nowhere did I say that I would sacrifice my comfort to save a penny. IF comfort levels being equal, I will choose the more economical option of dash versus generator (whichever is better). But c'mon folks, I didn't set out to be lambasted by people that have utterly nothing of value to add to the thread.

For those of you that offered valuable opinions and insight, thank you! Your assistance was appreciated.

To the few curmudgeons like Mr. Dezolen...

[dlaughlin]

Originally Posted by FIRE UP

Trying to estimate a fuel mileage difference due to the use of A/C in not only a heavy diesel powered coach or, a small 22' Class C, for about 99.9% of the drivers out there, is basically impossible. There's many reasons, hills, slow driving and acceleration conditions (heavy traffic), head winds, actual speed (higher vs lower) and more.
...
There are people out there that say that, running with their headlights on costs more money. Yeah sure it does. Again, there's so many variables in and on a trip, that trying to calculate that kind of miniscule difference, IS IMPOSSIBLE.

Scott - these are two very good points, especially the variables you referenced. Whereas with our old gas rig, running the dash A/C, as I stated, made a noticeable difference. It doesn't seem like there's much of a difference, if any at all, on a DP. I knew I couldn't seek empirical data from here, rather, I was searching for anecdotal evidence which I have certainly received!

[FormerBoater]

Originally Posted by dezolen

If you are so worried about fuel consumption don't run genny or dash ac. But then driving at highway speeds with windows open creates more drag and mileage will suffer.
Perhaps you should stay home and save even more.

Folks, we have a winner!

Award: 10+ points for rudeness

Award: 10+ points for a Gasoline Powered Class A owner responding to a topic that he/she knows nothing about

Award: 10+ points for giving a virtually new member of this forum some reticence in posting good questions on this forum and likely leaving a bad taste in their mouth.

To the OP, you will not notice a difference in available engine power when running your dash A/C under most conditions. Now, if it is a long 6% grade like Fancy Gap in August..you might just want to depend on the roof A/C's as you pull the hill.

[Davdeb1]

I see you bought a 300 HP diesel. If your gasser had a marked decrease in fuel mileage, I'm sure your diesel will also have a decrease. Fortunately, in your manual for the Genny it will show how much fuel you will use at different loads. Running down the road at 60mph with a coach that gets 8mpg, a 10% decrease in mileage is .8 or .8gph if you stay at 60 mph. I'm sure you could do the math, I use this to explain my logic. My Onan 7500 uses about .5 gph. At 60mph I'm saving about .3 gallons of fuel every hour.
Diesel engine will give about 25-40% better fuel consumption. Its probably logical to assume that your new unit running the air will probably do better than 15% loss by 25-40%. This should come to somewhere between a 9-11% reduction instead of the 15%.
My logic and could very well be flawed. My short answer is no matter what fuel mileage you get, conditions and speed will never affect the gph on your Genny. In extreme heat, headwinds, hilly terrain or stop and go traffic, the Genny will always be more economical to run. I do not feel a DP with the length of the hoses required could be more efficient running an AC compressor than your front engine gasser was.

If your gasser was getting 6mpg, and you had a 15% reduction, your mileage was 5.1mpg.
Conversely, with 25% better mileage your DP will get 8mpg, with a 10% reduction from the AC you will get 7.2mpg.
Your gas engine will cost your .9mpg while your diesel engine cost you .8mpg.
I'm using these figures because my 330 HP 40ft DP gets from 9-10 depending on conditions. I suspect yours should get similar.

[DMTTRANSPORT]

Originally Posted by DJJ

Sorry, but they are different pumps. At least on my Freightliner Dutch Star with a side radiator.


Jeff
2003 Dutch Star, 3126B Cat.

So you have a tank for hyd and one for PS fluid?? The Spartan has one tank that runs the Fan, Jacks & PS....I see no one will comment on the 60 hp loss from the fan..don't know where people come up with this merda!

[DMTTRANSPORT]

Originally Posted by Davdeb1

I see you bought a 300 HP diesel. If your gasser had a marked decrease in fuel mileage, I'm sure your diesel will also have a decrease. Fortunately, in your manual for the Genny it will show how much fuel you will use at different loads. Running down the road at 60mph with a coach that gets 8mpg, a 10% decrease in mileage is .8 or .8gph if you stay at 60 mph. I'm sure you could do the math, I use this to explain my logic. My Onan 7500 uses about .5 gph. At 60mph I'm saving about .3 gallons of fuel every hour.
Diesel engine will give about 25-40% better fuel consumption. Its probably logical to assume that your new unit running the air will probably do better than 15% loss by 25-40%. This should come to somewhere between a 9-11% reduction instead of the 15%.
My logic and could very well be flawed. My short answer is no matter what fuel mileage you get, conditions and speed will never affect the gph on your Genny. In extreme heat, headwinds, hilly terrain or stop and go traffic, the Genny will always be more economical to run. I do not feel a DP with the length of the hoses required could be more efficient running an AC compressor than your front engine gasser was.

If your gasser was getting 6mpg, and you had a 15% reduction, your mileage was 5.1mpg.
Conversely, with 25% better mileage your DP will get 8mpg, with a 10% reduction from the AC you will get 7.2mpg.
Your gas engine will cost your .9mpg while your diesel engine cost you .8mpg.
I'm using these figures because my 330 HP 40ft DP gets from 9-10 depending on conditions. I suspect yours should get similar.

....And the BOOK is always right!

[jondrew55]

Originally Posted by Davdeb1

I see you bought a 300 HP diesel. If your gasser had a marked decrease in fuel mileage, I'm sure your diesel will also have a decrease. Fortunately, in your manual for the Genny it will show how much fuel you will use at different loads. Running down the road at 60mph with a coach that gets 8mpg, a 10% decrease in mileage is .8 or .8gph if you stay at 60 mph. I'm sure you could do the math, I use this to explain my logic. My Onan 7500 uses about .5 gph. At 60mph I'm saving about .3 gallons of fuel every hour.
Diesel engine will give about 25-40% better fuel consumption. Its probably logical to assume that your new unit running the air will probably do better than 15% loss by 25-40%. This should come to somewhere between a 9-11% reduction instead of the 15%.
My logic and could very well be flawed. My short answer is no matter what fuel mileage you get, conditions and speed will never affect the gph on your Genny. In extreme heat, headwinds, hilly terrain or stop and go traffic, the Genny will always be more economical to run. I do not feel a DP with the length of the hoses required could be more efficient running an AC compressor than your front engine gasser was.

If your gasser was getting 6mpg, and you had a 15% reduction, your mileage was 5.1mpg.
Conversely, with 25% better mileage your DP will get 8mpg, with a 10% reduction from the AC you will get 7.2mpg.
Your gas engine will cost your .9mpg while your diesel engine cost you .8mpg.
I'm using these figures because my 330 HP 40ft DP gets from 9-10 depending on conditions. I suspect yours should get similar.

I guess if we're counting pennies here and comparing diesel to gas we should include the fuel cost difference between the two. I'll leave the math as an exercise to the reader

[FormerBoater]

Originally Posted by DJJ

Sorry, but they are different pumps. At least on my Freightliner Dutch Star with a side radiator.


Jeff
2003 Dutch Star, 3126B Cat.

Not so on the Spartan Chassis built for American Coach in the 1998 model year.

[CampDaven]

All arguments aside....How far are you going?
If you get 7.5 without and 7.0 with, over 1000 miles at $2.50/gallon the diff will be about 24 bucks.
Just sayin.....