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CecilD · 08-06-2017, 10:12 PM

We went from a 6,000# TT to a 10,000# 5er (both tow weights). Average mileage went from 13.6 to 11.2. 66% increase in weight, 21% decrease in fuel economy. Fuel economy with the heavier rig gets worse faster when it turns to stop and go or going up hill.

FTWLino · 08-06-2017, 10:13 PM

Quote:

Originally Posted by CecilD

We went from a 6,000# TT to a 10,000# 5er (both tow weights). Average mileage went from 13.6 to 11.2. 66% increase in weight, 21% decrease in fuel economy. Fuel economy with the heavier rig gets worse faster when it turns to stop and go or going up hill.

Thanks for the info!

sellis1053 · 08-07-2017, 06:55 AM

Quote:

Originally Posted by lynnmor

If you are currently getting 9 mpg, that is close to being a miracle.

Nothing miraculous about it. I have a 2014 with the 6.4 and get between 10 & 11 pulling a 31' travel trailer about the same weight.

guy65 · 08-07-2017, 07:46 AM

Lynnmor- some people just simply know, how to drive and use the power of the vehicle efficiently. I get with my 8000# loaded VIBE thanks to the aerodynamic nose with my 1500 around 11mpg- even up in the Georgia mountains towards Helen. It was just not important enough for me, to make a picture of the computer to show it to everyone.

patriot07 · 08-07-2017, 08:40 AM

An 11,500 lbs 5th wheel is a lot of trailer, even for a 3/4 ton truck. With 3k extra lbs and the extra wind resistance due to height, I think you're probably looking at a reduction down to 7-8 mpg.

The unfortunate part may not be as much related to the cost as it will be your range. 7 mpg on a 31 gallon tank isn't very far. On the flip side, you'll be going through the gas so fast that you'll be able to actively watch the needle drop.

If you want to increase mpg, slow down. Works 100% of the time.

lynnmor · 08-07-2017, 09:03 AM

guy65 - I only get 11.13 to 11.70 towing with a diesel pulling less that you. A diesel should do much better than a gas engine. I cruise at 62 -63 MPH and traveled all of the lower 48 and 3 provinces. It is quite obvious that I have no clue how to drive.

guy65 · 08-07-2017, 09:58 AM

Quote:

Originally Posted by lynnmor

guy65 - I only get 11.13 to 11.70 towing with a diesel pulling less that you. A diesel should do much better than a gas engine. I cruise at 62 -63 MPH and traveled all of the lower 48 and 3 provinces. It is quite obvious that I have no clue how to drive.

just because you do something one way for 30 years, does not mean, that you've done it 30 years the right way.
I learned driving from my grandpa, who was in the trucking business for a long time, in a time, where it was essential to drive fuel saving, because there was not much fuel. Later he opened a driving school (which still is in business today- my cousin has it).
if you drive and use the torque of your engine optimal, you can save over 10% on the same distance.
Also- as tech, I can tell you- and you can even proof it mathematically- the way you drive is, what saves you fuel.
Example: speed up as quick as you can to reach your desired speed. the longer you cruise, the more fuel you save. if you speed up slowly, you use a lot of fuel over a long distance to reach your travel speed- this is, where you loose. Also- if you speed up to little more than desired, and get off the gas, until you have your desired speed, your transmission usually goes into a lower gear earlier and there is another fuel saving possibility.
also- I pump my tires up to the max- even though I pay little more in tires, because they might be done little earlier, the fuel I save is more, than the more I pay on tires, because harder tires have less resistance.
the next thing- lot of people lift their trucks- I bought mine, as it don't even have the elevated height of 1 more inch. might looks poopie, but that's where I save on less air resistance. I drive on the highway with 90% cruise control- in older cars it was not a fuel saver, in newer cars it is. Also, if you feel, the truck could stay in lower gear, just hit the gas for a moment, the transmission will shift up, the rpm goes down and you save fuel. one criteria of the camper was the aerodynamic nose, which also saves gas. If you also take care of your suspension, put hard hd shocks in and improved, progressive springs, this will save you another bit. you see- it's the summary of the whole package- equipment and driving, what saves you gas. Route planning is also part of it- do I take the slight longer route around, or do I drive over the hill. Do I take the short cut with 40mph speed limit, 20 stop signs and 10 red lights, or do I stay on the highway?
Plus- even though they have similar power ratings, not every engine is the same- if you have a ford 6.7 diesel, it will be always more thirsty than a cummins, where the rpm in combination with displacement plays a role. The characteristic from th v8 is completely different from the inline 6. the V8 will have his advantage on high speeds, the i6 on lower end up to travel speed.
There are so many factors- and I only know, because I spent 4 years longer in school than others and combined that with experience by doing.
At the end- the most value to your fuel consumption is in your right foot.

lcboy · 08-07-2017, 06:57 PM

I have a 32 ft vibe 6500 lbs dry and I get around 11.5 mpg doing 65 mph but I use cruise and try to coast as much as possible when I see anything up ahead and try to keep speed steady. Braking and gassing to get back up to speed will kill mileage. I use 100 percent gasoline and keep tires at max pressure. I stay in the slow lane and try to never catch up with the person in front of me. If they do 65 I do 64 so there will be space in front of me so I don't have to hit the brakes and then give it gas to get back up to speed.

guy65 · 08-08-2017, 10:28 AM

Icboy- exactly that's the way to do it. but if you think, you got to show everybody your overwhelming power of your diesel by passing them with 75mph or faster by stepping extra hard into the gas pedal, it ain't working and that's the reason, why a diesel don't get better fuel mileage than a gasser.

patriot07 · 08-08-2017, 08:34 PM

Quote:

Originally Posted by guy65

Icboy- exactly that's the way to do it. but if you think, you got to show everybody your overwhelming power of your diesel by passing them with 75mph or faster by stepping extra hard into the gas pedal, it ain't working and that's the reason, why a diesel don't get better fuel mileage than a gasser.

Diesel and gasser driven the same way - the diesel will nearly always win in mpg.

Driving 65 mph on the highway unloaded, my ecodiesel will top 30 mpg. Towing at 65 mph, I get about 12 mpg towing my trailer @ 6,500 lbs loaded.

mtofell · 08-08-2017, 11:49 PM

I've made a similar jump to what OP is proposing with both a 2006 Duramax (diesel) and my current 6.4 Hemi (gasser) - 8000# TT to 11000# 5th. With both trucks I saw maybe a 1-1.5 mpg difference.

The whole TT vs. 5th wheel debate with respect to wind resistance went around on a thread recently and the opinion of some pretty smart folks was that the 5th isn't much different, if any for the same weight. Yes, it's taller but it's also closer to the truck so the two travel more as a single unit. The air being thrown over the front of a truck hits the front face of the TT and really causes a drag. I'm paraphrasing from what I remember but it makes some sense to me.

Basically, it's closer than a lot of people think for a given amount of weight.

guy65 · 08-09-2017, 06:24 AM

Quote:

Originally Posted by patriot07

Diesel and gasser driven the same way - the diesel will nearly always win in mpg.

Driving 65 mph on the highway unloaded, my ecodiesel will top 30 mpg. Towing at 65 mph, I get about 12 mpg towing my trailer @ 6,500 lbs loaded.

The point is, that if you're used to drive a gasser and apply the way you drive a gasser to the diesel, you will need more diesel. a diesel wants to work and uses less fuel in lower rpm. from this point of view- yes, a diesel supposed to use less gas with the same condition, than a gasser. Both have their advantages and disadvantages. Also- if someone says, that he uses the same amount of fuel with a 1l bigger, turbo aspired diesel engine, than a smaller gasser, then he should not complain, but be happy. and if you would take more fuel than a 2.7l bigger gasser with 2 more cylinders with a way smaller, 2cylinder lesser turbo aspired diesel engine, you would have a serious problem.

trenchmonkey · 08-09-2017, 06:34 AM

Georgia "mountains"?? Now that's funny!!

guy65 · 08-09-2017, 08:10 AM

Quote:

Originally Posted by trenchmonkey

Georgia "mountains"?? Now that's funny!!

well...for someone living in south Dakota, a 100ft hump is already a mountain. so are for people around here the blue ridge and smokey mountains. Of course, they can't compete with the rocky's. Even though in their prime, they where higher and worse... but thankfully we have erosion and they are still high enough to call them mountains.