real world mileage, diesel vs gas

[chadk66]

Am contemplating an early to mid 2000's Class A. Will be pulling an 18' enclosed trailer. Am leaning towards a diesel pusher. Dealer is trying to tell me a gasser will get as good a mileage and as good a power. I'm a diesel mechanic and I'm not buying it. What are some real world mileages and performances out there on both.

[chadk66]

bshpilot wrote:
if manufactures could (actually) achieve 25% better fuel economy via a tune or injector swap THEY WOULD !

I always chuckle to myself we i hear people in campgrounds claim theyre getting 18 or 20 TOWING their travel trailers. sheesh !

you can believe what u want I guess.

[chadk66]

holstein13 wrote:

chadk66 wrote:
Achieving better mileage comes from a combination of things. Altered injection timing is an important part of it. Also changing the amount of fuel at appropriate times to achieve maximum power output at the correct time. It's rather mind boggling actually

What about emissions and longevity? I'm assuming the changes to timing could have a negative effect on emissions and / or longevity. Otherwise, wouldn't every manufacturer do it?

emissions aren't an issue in ND. If u choose to abuse the power you can tear stuff up. If u mind your business and keep your foot out of it your fine. You aren't gonna do that with motorhome. But yes u can tear a truck up if your stupid lol

[bshpilot]

if manufactures could (actually) achieve 25% better fuel economy via a tune or injector swap THEY WOULD !

I always chuckle to myself we i hear people in campgrounds claim theyre getting 18 or 20 TOWING their travel trailers. sheesh !

[holstein13]

chadk66 wrote:
Achieving better mileage comes from a combination of things. Altered injection timing is an important part of it. Also changing the amount of fuel at appropriate times to achieve maximum power output at the correct time. It's rather mind boggling actually

What about emissions and longevity? I'm assuming the changes to timing could have a negative effect on emissions and / or longevity. Otherwise, wouldn't every manufacturer do it?

[chadk66]

mike brez wrote:
My 7.3 has chip,injectors,turbo,4inch straight pipe exhaust,HPOP some trans work. I haven't checked my mpg in 10 years with this truck but I think I was getting about 15 mpg. I'm also spinning 35 inch tires.

the 7.3 was just never an animal you could improve economy on much for some reason. Not like the 6.0. Or the cummins which is the easiest to help out

[chadk66]

Achieving better mileage comes from a combination of things. Altered injection timing is an important part of it. Also changing the amount of fuel at appropriate times to achieve maximum power output at the correct time. It's rather mind boggling actually

[holstein13]

If you are a diesel mechanic, then you should not hesitate to get the diesel. You already know the differences between a diesel vs gas and you can quickly, easily, and economically maintain and repair your diesel engine at your shop or employer's shop. BTW, where would you get your gasser serviced? I suppose you'd probably work on that as well, but it wouldn't be nearly as convenient for you.

Not to state the obvious here, but if you can improve your mileage even 10% from stock then it's inconceivable that any gasser would provide you better mileage given the same weight, design and speed characteristics as your diesel.

Finally, it's easy to increase gas mileage by 25% or more, just slow down by 15%. You don't even need to be a mechanic to do that. 😉

OK, I know that's not what you meant. But I'd be very curious as to how you'd hope to achieve a 25% reduction in fuel consumption with modifications.

On edit: I read how you hope to increase mileage. Please let us know how that works out for you. Intuitively, I can't see that giving you a 25% increase in mileage with rigs our size and weight, but it might help some.

[mike_brez]

My 7.3 has chip,injectors,turbo,4inch straight pipe exhaust,HPOP some trans work. I haven't checked my mpg in 10 years with this truck but I think I was getting about 15 mpg. I'm also spinning 35 inch tires.

[chadk66]

My assumption is based on what i have done with my own diesel pickups as well as my sons. The older cummins are actually pretty easy and cheap to get better mileage with. My son has a 1999 3/4 ton dodge that has a 5.9 in. When he first got it he was getting 12-14 pulling his 34' toyhauler. Of course he stuck a chip in it after a short while and started getting about 16. Then he decided to purchase 100hp injectors so we threw those in and he started getting 16-18 pulling it. Same thing happened to my 05' ford with a 6.0. Pulling my enclosed trailer it would get twelve constantly. Put a tuner in it and got 14-16 with it. No other mods. It's pretty amazing what they can do for mileage. I have a buddy that has an older cummins also. He went a little more nuts with his and went with bigger injectors yet and a bigger turbo. But then installed methanol injection. He gets mid twenties on the highway just cruising with no trailer. He doesn't pull anything but I'd guess it would be pretty surprising what he would get. Methanol is actually the best gain for the buck and it keeps the egt's down there when pulling a load on hills.

[bshpilot]

WILDEBILL308 wrote:

Ok I will bite. Tell me about how you are going to get 25% better mileage chipping a diesel pusher.
Bill

from snake oil & PURE BS !

[WILDEBILL308]

chadk66 wrote:
the reason I want to talk mileage is because I'm pretty confident I can make the diesel produce 25% better mileage and far more power for a rather low price.

Ok I will bite. Tell me about how you are going to get 25% better mileage chipping a diesel pusher.
Bill

[Kidoo]

I got 10.5 average on a 7000 miles trip, some flat road, some head wind, some Colorado high pass, some town and country. No toad, motorcycle on the back rack with a 300 HP Diesel 34 feet MH.

But fuel is allways around .50 cent higher than gaz. The DP is very quiet, it just wisper and is has a very smooth Alison trany, up or down hill. The gene is quiet and quite efficient in term of gallons per hour.

I got 12.1 average with a Bigfoot 10.4 truck camper on a Ford 6.0 Diesel 2006, two 13000 miles trips to Alaska.

1.6 MPG on 26000 miles would have cost about $650 more each trip if I would used the MH instead of the TC. There is also the cost for maintaining the MH which is important to consider, and in my country, it cost me 800 a year for licence plate, the TC cost no plates at all, it does cost 375 for the plates for the pickup, but I need another vehicle with the MH, no choice.

The difference in $$ is not what's important for me, the type of MH must match your type of travel. For me, the TC was the most versatile camper to go to AK, different story when I go south for long time camping, I much much prefer the MH.

[SS_Slacker]

5.9 Cummins 300hp stock and I never cruise over 65mph . Average over the past 65,000 miles is 8.4 towing a 3,200 pound boat and trailer. Not towing the average is 9.5 mpg and I reach the 10's if I have a good tailwind.

[tropical36]

chadk66 wrote:
Am contemplating an early to mid 2000's Class A. Will be pulling an 18' enclosed trailer. Am leaning towards a diesel pusher. Dealer is trying to tell me a gasser will get as good a mileage and as good a power. I'm a diesel mechanic and I'm not buying it. What are some real world mileages and performances out there on both.

He's most likely correct, except that most of the DP's are a lot bigger and a lot heavier. If fuel is a real concern and I don't know why it would be, keep in mind that diesel fuel usually costs more.
Biggest concern with traveling costs and not what you were asking, is depreciation per mile, so picking the right used coach can go a long way in this regard and make it seem like you are getting free fuel for years on end.

[JetAonly]

chadk66 wrote:

JetAonly wrote:
I logged 20k miles at 8.3 mph without a towed. Its about 7.6 with 5k miles of a 6k towed. I pull Eisenhower west bound tunnel at 28mph. It is 9% at 11000 ft at the approach to the tunnel. Total weight is about 39,000lbs. I normally run 68mph on the cruise…but I digress.

Unless you start running 50-110k miles a year fuel mileage is a red herring and you focusing on one of least important aspects of Class A ownership. Some B motor powered MH have 5k tow restriction. You will never see 12mph as a long term average. You don't say how much your trailer will weigh. The other concern is every hill you go up you, have to come down. You will need and exhaust or Jake brake, or a transmission retarder.

for all intents and purposes it's really flat where I'll be running. The trailer will only weight 5-7K I would suspect. just a light 18' cargo with a couple motocross bikes and a little gear and tools. Nothing real heavy. As a couple stated on here they can push close to 10 mpg with a cummins. And those I'd assume are stock. I should be able to make twelve with that same setup with injectors and a chip. I'm not concerned with the transmission they are built to withstand far more than I would be asking for it to do. We are making pickups put out 600 hp with stock trannies with no issues and pulling 40' toy haulers with them. I just like the idea of having everyone under one roof so they can move about and eat going down the road. I honestly don't care if I get better mileage than a gasser, it'll just be fun to try to see how good I can make it in that regard.

Good luck!