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Cummins fuel mileage?

Discussion in 'Diesel Tech' started by Mike97ZJ, Jan 15, 2004.


  1. Mike97ZJ

    Mike97ZJ
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    I'm thinking about picking up a late 90's Cummins for a possible plow truck and/or tow rig.



    I was wondering what sort of mileage I could expect to get with a stock extended cab automatic. I just mean during normal driving, btw, not plowing or towing.



    Thanks for any info.



    edit: Maybe I should have read page 2 before posting this. I can't believe some of you guys are getting 20 and over. That's just insane with a truck that big. I've GOT to get me one.



    Fell free to still post your mileage though.
     

  2. FireRescue

    FireRescue
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    Are you considering a dually? What gears are you thinking? The 3.55 gears usually yield 1-2 MPG's better than the 4.10's and the SRW trucks 1-2 better than the DRW.



    It also depends a little on what year you are looking at. The early 24v's (98.5-99) were typically not the best with MPG's. My friends 99, 4x4, SRW, w/ 4.10 gears never got over 17.5, he usually got 15-16. On average the 12 valve motors seem to be a little easier on fuel. Of course there are exceptions to every rule. I have another friend that went from a 1995, SRW, 4x4 w/ 3.55 gears and he typically got 21-23 MPG's with that truck. His 00, SRW, 4x4, w/ 3.55's gets between 19-21.
     

  3. 98ramtough

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    My truck is a 98 srw 12 valve 4x4 cummins 5 speed and I get 20-24mpg on the highway/18-19 in town. The 5 speed will get you better mileage. Look for a late model 12 valve, they get the best fuel mileage and are cheapest to BOMB.....
     
  4. tpruitt

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    I can get about 19mpg with 37 inch tires and 3.54 gears. The mpg is actually around 22mph though because spedometer was never recalibrated.
     
  5. Mike97ZJ

    Mike97ZJ
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    I'd want a SRW truck, I don't need a dually. As far as gears, I have no idea. They come with 4.10's or 3.54's? I guess I'd end up with whatever came in the truck. I'm talking used here. I DO think I'd prefer an auto tranny though.



    After what I've read here, I'd look for a later 12V. What year did they stop making them? I honestly don't know alot about them, which is why I'm asking questions now. I probably won't be in the market for the truck till September.



    Also, if I was to get a truck with 4.10's, would putting on 35" AT's improve the mileage? I know installing larger tires lowers the effective gear ratio, would the 35's and 4.10's get good economy?



    And what do you mean by cheapest to "BOMB"? Do you mean mod? I know diesels can make crazy power, isn't that really big bucks though? Or are there a few low buck mods that can help power and economy?



    Thanks alot for all the advice.
     
  6. jkgdiesel

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    Get the 12v Cummins. The last year they made them was mid 1998. There are 24v and 12v 98 trucks out there so look carefully, but it is not hard to tell the difference. My dually 98 12v came with 3.54s and I have heard after a few forums on here that most of them come with the 3.54s and the 4.10 was an option, so your probably going to find one with 3.54s.

    As for the choice of going to a different gear ratio, I would stick with the 3.54s if your not going to put big tires on it. I am going to go to 4.10s with my 37" tires.

    The 12v are great for power and the mods are considerably cheaper than that of a gas motor. Just give it more air before more fuel. You can get fuel cal plates that go in the injection pump and provide wonders of more power, but they also increase EGTs and smoke, so a pyrometer gauge is necessary. I got the complete Banks Power Pack, it was a little pricey but it gave me over 300 ft-lbs torque and about 130 more HP. I was amazed at the increase in fuel mileage I got to as they claimed.

    Get the 12v, no lift pumps to go out on you and kill your injection pump and a 12v is easier to learn about and work on IMO.
     
  7. Wt Mtn Terror

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    this mileage thing has me all confused, I have a 99 with 4.10's and 315's I'm getting about 14 mpg. according to the computer. I haven't recalibrated the speedo so how much is it off? Also before that I went from the stock 235/85 to a 285/75 and was still getting around 18? :shock: forgot to mention I have an auto too.
     
  8. CSARebel916

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    I have a 99 Dodge 3500 with the 24v Cummins and I get anywhere from 25 to 28 mpg durin the summer and as bad as 19 durin the winter.
     
  9. GotSmoke

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    Right now my fuel mileage just sucks. Im gettin under 15mpg. But that's also due to 38's and 3.54 gears with no fuel mods. During the summer/fall i was gettin close to 18-20mpg. Once taxes come in i'll be bumpin her up pretty good with mods so hopefully that'll get my mileage back up.
     
  10. kingofdodge

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    as far as BOMB/Mods go, The 12v is cheeper, i mean to pick up a quick few free ponies poke some holes in the air box and move the stock fuel plate forward, But, It all comes down to mechanical ability. The 12, to adjust timing you need soem special tools, and some time, and your stuck at that particular timing and HP rating, plus you have to know how to change it. With the 24 V Its all run by computer. So all ya do is plug in a box and it tells the engine to up the timing and fuel to make the more power. Most boxes out there will let ya choose between something like 40 hp and 90 fttq, all the way up to 160hp and 360fttq at the flip of a switch. So its kinda nice. And both will yeild aboutthe same mileage.
     
  11. Tango

    Tango
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    what do you get towing?
     
  12. BadAssBarbie

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    Automatic '98 24v and I get under 15 mpg normally...sometimes a lil' more out on the open road.

    My dad, on the other hand, with a 12v manual is pushing around 20 mpg. Go 12v... easier mods, too.
     
  13. frmnjj82

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    Do Cummins usually get worse mileage in the winter and better in the summer. Ever since it has been cooling off, I thought I would get better because I am not running my AC. With my truck in the summer I got 17 avg and now I am lucky to keep it above 16. I am reading on some sites here that other people are getting more than I am with the same truck. Could it be my lift pump or injection pump?
     
  14. BigGreenCTD

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    I got a 95 reg cab long bed srw 4wd ctd with 4.10s what could i expect milage wise? i just got it haven't filled up yet to check it.
     
  15. Boz

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    Winter fuel. In the summer the fuel is straight #2 but in the winter it is blended to help the fuel not gell. Winter mpg's are almost always less.
     
  16. steved

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    They get worse because they change the fuel characteristics to prevent gelling...called winterized fuel.



    My dad got mid 20s in his 95 and a high of 28mpg (4wd, auto, 3.55s, highway)...it was a dog in stock form though...his 99 24-valve gets 21mpg all the time....my 99 got between 17 and 26mpg (14.5mpg towing 10,000 pounds)...my 2004 gets between 15 and 20mpg (18mpg towing 5,000 pounds)...



    And I wanted to correct FireRescue's response...the SRW (2500) typically get better mileage than the DRW (3500)...if I read that right...



    3.55s are good for the average person, if you plan on towing/plowing get 4.10s...you will hate an auto as they will not hold up under these trucks without some serious $$$ in a rebuild.



    And as stated, 3.55 was standard, 4.10s were optioned...you will NOT find many dodge trucks with 4.10s and an auto unless someone special ordered it...I looked for about 6 months for a 4.10'd auto before I bought my 99 with 3.55s.



    And IMO, while the 12-valves were easier to BOMB, the 24-valves are becoming easier to mod anymore...what can be easier...plugging in a chip and having fun. TST offers an extreme chip for my 04 that would yield around 550 HP and 1200 ft-bs of torque, if their statements are correct. Plug and play for around $800.



    steved
     
  17. BigGreenCTD

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    wow so then i got lucky finding this auto with 4.10s. Its got plow bracket on front guy used for plowing before me i guess its also got some trans temp light by wait to start light. Manual said that was plowing option.
     
  18. steved

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    All the auto CTDs have the trans temp light...that is normal...but yeah, auto with 4.10s is not common at all.



    What do you get for mileage with the 4.10 auto??



    steved
     
  19. OnE54ToN

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    I get like 17-18 cruzin with 4.10s :bigthumb:
     
  20. BigGreenCTD

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    im not sure if its my timing which is off i believe or what but this the milage im getting is piss poor im calculating like 7 mpg something is totally outta wack, and i thought my old z71 was bad on gas this thing sucks a$$ and its not like im racing it around because it aint got no balls to do that :bluecry:
     

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