johnr9q

The original poster here again. Many of you have talked about the fact that the Dodge PU is like driving a brick down the road in terms of aerodynamics and weight. I know a couply people that have large class a RV's with Diesel pushers that repeatedly get 12 mpg going 65 on the flats. Talk about a brick, these rigs have to weigh at least 4 times what my rig weighs and aerodynamically are much worse. Why then shouldn't I get at least double what they get? Doesn't make since to me.
In terms of slowing the RPM down some on this thread talk of a "Splitter" Where can I get more info on it? How about putting larger diameter tires and wheels on the rig. Wouldn't want bigger just taller and maybe even less beefy to weigh less? My truck is totally stock except I put an aluminum flat bed on it as I built a pop top cabover camper that I carry on the truck much of the time.

BoostdCTD

Ever see a motorhome catch on fire? Ok how about after the fire went out. There is a frame, and a motor left. Point being they aren't really that heavy, if it weighed 4X a CTD then a CDL would be required to drive it.

Do you know what gear ratio you have? The overdrive unit can be found at http://www.gearvendors.com/ or also usgear has a site as well. Bigger tires are heavier, heavier tires cause mileage loss in stop and go but if they lower the RPMs into the right range the mileage will go up at cruising speeds.

infidel

In university wind tunnel tests there was less aerodynamic drag with the tail gate on and up. Tonneau covers also created more turbulence than an open bed unless the cover sloped from the top of the cab to the top of the tailgate. The sloping cover was the only thing in the test with better aerodynamics than a open bed tailgate up.
I get about 1 mpg less with a cab high fiberglass canopy on than open bed.

Try aiming your tailpipe out the back rather than out the side for added thrust

Eskimo

My Cummins weighs 7600lbs, and my friend's '95 American Eagle C8.3 Class A (40' I believe) is 30k.. No CDL required, and yes, it does weigh 4x what the CTD does..

he gets 9.5 mpg with a 16' car hauler and 4000lb 4wd on that, doing right around 5 over.

Mcmopar

You are joking?? Right?

Personally I think I do pretty well considering a guy I work with has a "Bug" 1.9 Diesel and only gets 44MPG. My 5.9 Diesel with 4 wheel drive and about 2 times the weight gets about 21 on the highway, and about 16 around town!!They way I figure it is he should get 3.1 times the mileage based on engine size alone. Now throw in the extra weight and 4 wd and he should get about 80-100 MPG. Apparently his car gets mileage.

CTD NUT

What we are really talking about here is BSFC.....Brake Specific Fuel Consumption..........or the ratio of how much fuel is used compared to how much hp is being generated.........There are MANY factors that affect BSFC and depending on the actual hp required to move a given vehicle, it is possible for a smaller motor to burn more fuel to make the required hp..........if the smaller motor is way out of it's useful BSFC range to make the required hp but the larger motor is in it's sweet spot, there is a potential for the larger motor to have a much better BSFC and burn less fuel.

96_12V

This conversation is starting to remind me of one i had with another bicycling enthusist. He had just dropped $75.00 for Titanium wheel skewers for his wheels, shaving about 2 ounces off his bike! While this alone was goofy enough (road bikers want to shave all possible weight to minimize resistance and increase thier capacity for performance) he then laughed and said, "Look if I eat a banana before I take off--I've just added half a pound--to myself!" In other words, such expensive fiddling really wasn't gaining him very much. Placing a dime in front of a dollar does not always yield a return.

BoostdCTD

I think it varies per truck design. Here is a link where a Pherd engineer claims 5-10% fuel savings on a Pherd F150. I have personal experience of it helping the mileage out by 1-2mph on a Cheby 4x4.

infidel

The tests I was refering to were done on a '97 Ram. I finally found the link to the website but it was gone. It had pictures in the wind tunnel with red smoke being released. With a tonneau cover the airflow balled up behind the cab, with the tailgate down it balled up under the tailgate. Tailgate up and no cover the smoke made a straight shot from the top of the cab to the top of the tailgate. I've read several times that the flow though type tailgates made of expanded metal or webbing are the worst for messing up airflow.

Raspy

I overheard a guy talking about his new Dodge Ram diesel pickup the other day. He said he thinks the auto manufacturers are in kahoots with the oil companies. And the proof is that all he had to do was put a Banks kit on his Ram and he "doubled the horsepower, the torque, and the mileage. Yeah, right.


Wetspirit

BoostdCTD

I'd have difficulty holding a straight face when someone tells me a claim like that.

Monty

Im having a hard time believing your friend is averaging 12mpg in his pusher. You almost never see an ISB getting over 10mpg in a class A. Let alone a 3126 CAT.

royta

kingofdodge7131

What he was talkin about was completly correct. If you want to think about it. Look at class 8 trucks. Pullin around 60-80k lbs and they get 4-6mpg, depending on many things though. Engines, gear ratios on what not. Unloaded they can pull into the 8s! WHO HOO. But then look at them. huge wind resistance. Not to mention 14 liter engines.

My 83 dodge Class C camper with the 460( i think it is) Gets around 6 mpg. Another guy in my town ( town of around 600 haha) as the same style camper with a cummins out of a 1st gen and he gets around 10.

Can i believe your friend gets 10 with his class A? Yes. But only in certain circumstances. Say at the speed limit. maybe pullin a small car.

I believe there gonna way a bit more than our rams as well. one there long. That 30k weight if you have a full tank of fuel, your LP, water, possible waste waters. generators, tvs computers tables and what not. The empty camper wont way much more but one ready to go could. ( I live in Forest City Iowa where we build all the Winnibagos. Worked there for about 3 weeks cant do factory work :P) But theres nuttin there. its a wood frame on a truck frame.



Now that ive rambled. Basically what im trying to point out is that its all not and eye for an eye comparison.

Semi trucks if empty can get 8. My ram with a 360 gasser gets 10. If I toted around approx 15k in teh back of that 1500 id get a lot less than 8.

my Chevette with a 4cyl isuzu gets around 30-35 My 99 gets 22 or so at 55-60 on the hwy. around 18 in town. now. My 04 with the same displacement gets 19 at exactly 55 if i treat her nice. I use to keep a pretty good record of my mileage with it on a spread sheet but was between jobs for a few weeks and didnt fill the tanks completly. Then lost the computer to a virus so i lost it all anyway. Angers me still today. Bought her new i wanted to know what she got. But i average around 17 compared to the 20 that the 99 averages. Same motor. same Final gear ratio.

I dont know the gear ratio diffrences between the 47re and the 48re. I know the 99 has 3.55 and the 04 has 3.73 Maybe the extra fuel is enough. Or maybe its that darn pilot injection. I hate that with a passion. I dont care if my engines are quiet or not i want my power and mileage. My uncles v10 can get 16 hwy if hes nice to it. i might get 19 but diesel is 25 cents more exp now so im no farther ahead. Both pull great so heres what i ahve to finish with


Hope you get better over worse but dont worry if its not the best because someones always gonna have some sort of beter combo than you do anyway!

fearthedeere

Dude i dont mean to sound like an EDIT but if u want better fuel mileage get a hybrid car.