I don't know that much about diesel engines and I'm attempting to educate myself. In reading the forums here I've picked up two things.
First: Diesel fuel has a higher energy capacity than gasoline based on the BTUs per unit weight.
Second: Diesel engines are more miserly on fuel consumption based on the combustion ratios (14:1 air:fuel for gas engines, at least 30:1 for diesel engines.)

So, why in general do diesel engines in trucks get lousy mileage? Is it the high horespower numbers? ...or is it something else I'm not getting? ...or do diesel trucks get great MPGs and I'm being unrealistic?

 

My neighbors gasser F250 15 mpg, my 3500 dually 18.8 mpg. He has to use medium grade @ $1.65 gallon to my $1.45 gallon. I had a gasser Chevy 2500 that towed my smaller trailer (6000 lbs) at about 5 to 6 mpg trying to keep up with traffic. My 3500 towing bigger trailer (8080 lbs at the scales) 12.8 mpg doing 75 mph. I’m happy.

 

bobomonkeyboy I am not sure where you get the lousy fuel milage thing. Many of the members are getting 18+ mpg on a 7000 lb truck. and to boot the fuel milage in many cases is double that of a gasser when pulling a load. the H.P. is not exceptonaly high on a diesel but the low end torque is where a diesel really has the advantage. I don't think anyone buy's these for milage untill you start pulling a load then the difference is considerable. Put 6-10,000 lbs in back of your diesel and run it up a hill now you know why you bought it

 

To put it in your words, you are being totally unrealistic. I have a gas van here and my diesel grossing 30,000 gets better mileage. I have a four cylinder Jeep pickup here also and it gets 16 reliably because it is a 4x4. The near 8000 pound dodge gets around 20 and it is a 4x4. Where in tarnation are you coming from?

 

7000# 4X4, 15.6 MPG per the computer with only 4500 on the ODO. I got 16 MPG with a 5.3ltr Chevy and it only weighed in at about 4800 and was a 2wd.

If this is lousy milage, I'll take it, it's only gonna get better from here!

 

It comes dwn to weight.....my semi can get 14 mi per gal if no trailor is hooked up to it...........as soon as that happens I get 6,or 5 or4 or ?????????/Know what I mean vern?????

 

Hey BoBo, are you just monkeying around with us??

 

I just saw your Signature 2004.5. You haven’t had a chance to break in your truck yet. It will not get good mileage until after break-in. Here is how Cummins answers this.
http://www.cummins.com/na/pages/en/p...4A0004AC33EA57
Here is the link to all this info.
http://www.cummins.com/na/pages/en/p.../faq/index.cfm
Give it a little time and break it in as Cummins says and don’t baby it. Soon you will be bragging about how great your truck is.
Good Luck with the new truck.

 

Some trivia: Efficiency is the no of btus that come out at the crankshaft in relation to what went into the engine. The higher btus per gallon/pound/dollar don't matter for efficiency. (They will do for fuel mileage thoug, and for fuel economy)
The mileages you read here are sometimes quite low because dragging a big trailer and drag racing will need lots of btus per mile.
I think that the average diesel driver tends to stand on it much more than the average gasser driver since it won't bankrupt him. Diesels are frequently used commercially to pull trailers or haul heavy weights.
AlpineRAM

 

I've come to my senses with a little bit of thinking (and a lot of help from the posters ). I guess I'm still in a little bit of shock coming over to the truck world from a VR6 Jetta getting 30+mpg. I never compared gas truck to diesel trucks. Duh!

 

Just compare a gas powered Jetta to a TDI Jetta at 70mpg(The new 2004's)!

 

Hey Haulin in Dixie is tarnation north or south of the line? my mother is from the south and always where in tarnation I had been, I also had the tar beat outa me a couple times.
BoBo How many lbs would that Jetta haul ? ya see if you haffta make 30 trips to haul as much as 1 trip with the CTD then you are really only getting 1 mpg or thereabouts (just east of tarnation)

 

Blackjack--actually, my jetta is/was set up to tow. I have a 6x12 utility trailer that I would use to haul my tractor, leaf shredder and misc. down to my Dad's to clean up in spring and fall. About 900 lbs. My mpg dropped to about 25 or so on those trips doing 75 the whole way. Not to bad for a little gasser.

 

Tarnation is just over yonder a piece.

I'm transplanted from central New York in the mountains.

 

Bobo's sig:

ON ORDER STILL!!!:
2004.5 2500 HO CTD 6-spd 3.55 rear
Still stock but fully loaded Laramie
4X4 SWB

Don't you mean the 3.73 rear? Also, you're truck is still on order, and it's still stock? You haven't bombed it while it's working it's way down the assembly line?

(And isn't it Marlboro? I know, it depends on where you look. )