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RAM V10 mileage-Any way to improve MPG?

20K views 69 replies 14 participants last post by  cjohhny 
#1 ·
Greetings all...new member...new to Dodge Trucks.

I recently purchased a 99 Ram 2500 V10 (yeah I know...$3.00 a gallon...bad timing on THIS purchase!!) and apart from the usual steering problems you've all covered in excellent detail here, I'm wondering if I can improve the mileage to better than the 7.5 I'm getting now.

It doesn't have stock width tires so I know that getting rid of them will improve mileage but are there any tips n tricks anyone knows of? 
I installed Bosch 4 platinums but I can't say as I like them very much. I lost 1/2 a gallon in mileage with them compared to the OEM Champions and need to get them out of it yet. Filters are all new.

Will going with a limited slip diff and getting rid of the locked posi pumpkin at the rear diff do anything for mpg (and possibly helping get rid of the bunny hopping around corners at low speeds)

I was thinking about yanking out the V10 and trying to shoehorn a hemi in there...is there any reason other than the need to change electronics why that wouldn't work?

OK..that's enough for now from the newbie.  ::)

I love the truck but I only wish it would pass gas stations as well as it passes everything else on the road.

Thanks! I'll be looking forward to your replies!
 
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#2 ·
Attempting to swap a hemi into that rig opens a whole can o' worms.  Besides the electronics, you would also need a tranny, and Tcase if it is a 4x4.  I am not saying it cannot be done, but it would be a loooong time before you paid off teh cost of converting with fuel mileage savings.

My old man managed 8.5-9 mpg around town with his '01 V10 4x4.  The only modifications were true 3" duals and a K&N drop in.

Every time I drove the beast I got comparable mileage to you, 7-7.5.  A light foot may be about all you can do. :-\  That is 488 cubes of fuel thirsty beast....

-SM
 
#3 ·
whiner
that's not much worse than my worn out 318, and it has no power to go with the sucky gas mileage.

Anyways, as suggested a better flowing exhaust and intake could help some.  Even if only 1 mpg improvement, it won't take too long to make the cost back up at almost $3 per gallon.
Skinnier highway tread tires, at max pressure, could help as you mentioned.  And of course, going easy on the skinny pedal.
If it's feeling rather strong off the line, and you wouldn't mind loosing a bit of giddy-up there, going to higher gearing will help too.
Can't see a limited-slip doing anything for mileage.

There's another thread going somewhere (Vehicle Help, Technical, or Open boards.  Can't remember which) with an arguement over tailgate down, full bed cover (hard toneau) or full topper.  may find it and see if any of the theories there interest you too.
 
#4 ·
Thanks guys. Great site! I'm enjoying it.
That's the kind of reply I was looking for...no BS just the Fax. Scrap the hemi idea. The truck has to be a daily driver so can't be down for a month or more to make the conversion. Looks like it's down to skinny tires and gear changes.

Yeah, in retrospect it wasn't the best purchase I've ever made. I got giddy when the kids all grew up and moved out and just wanted a toy. At my age it's either toys or chucking it all for a shiny red Corvette and a 19 yo blonde (or is that blonde 'Vette and shiny redhead..I get confused)  ;D....
I think I would have gotten better mileage from the 'Vette and the blonde..and that's including the cost of Viagra.    ::) ;D

Thanks again. I have some forum searching to do for tranny repairs for the beast in question.
 
#5 ·
RAM10 said:
Will going with a limited slip diff and getting rid of the locked posi pumpkin at the rear diff do anything for mpg (and possibly helping get rid of the bunny hopping around corners at low speeds)
Assuming its a factory set-up and not an open diff, than it is a limited slip. It wouldn't have a locker unless the previous owner installed it. Also, "posi" is GM's name for a limited slip, it's the same thing. ;)

Regardless of what is in your diff now, changing it will not affect mileage.
 
#6 ·
The width of your tires won't adversly affect your mpg either, taller tires will affect it much more.  You could try going with a slightly taller tire and see if your mileage improves on the highway.
 
#7 ·
Dodge 85 RC said:
The width of your tires won't adversly affect your mpg either.....
Wider tires = greater rolling resistance (i.e. friction) which can lead to worse fuel economy. But I do agree the diameter of the tire has a more significant effect.

-SM
 
#8 ·
Slanted_Mind said:
Wider tires = greater rolling resistance (i.e. friction) which can lead to worse fuel economy. But I do agree the diameter of the tire has a more significant effect.

-SM
...and the additional weight of a wider tire takes more energy to get rolling.
 
#10 ·
  The tires weight,  and a rear with a tight diff that makes the rear jump in turns or binding WILL effect your mileage quite a bit,  any binding in the drivetrain will effect mileage.
  I would use ac rapid fires over the bosch
 
#11 ·
Evildriver-3 said:
 The tires weight, and a rear with a tight diff that makes the rear jump in turns or binding WILL effect your mileage quite a bit, any binding in the drivetrain will effect mileage.
  I would use ac rapid fires over the bosch
I assume the "bunny hop" he explains is the normal give and grab that a LS will do on a corner while giving a little throttle when there is a bit a loose gravel or dirt on the pavement .
Unless a person drives around corners all day, it won't affect mileage.
 
#12 ·
      That isn't true....you do realize if one tire is at 38 and the other is at 33 it will make a difference and there will be some binding... That means you don't need a turn to bring on added force and most roads have turns in them,  and slight turns in them then they are straight for any period of time.
  If such a thing was true then the syn oil in the driveline wouldn't make a difference either...everything adds up and you might not think it is enough,  but it's enough to add to mpg decreases,  running syn everywhere and over inflating the tires and lighter wheels and lighter driveline parts will always help mpg and power increases... just turning 1 tire rather then both in an open diff will make a difference...
 
#14 ·
    Have you actually checked....i get 20 mpg with my crew...selectable lockers..(read open diffs turning only 1 wheel), over inflated tires, syn oil,  light wheels.
 
#15 ·
Of course I've checked, or I wouldn't have made a claim.

If he is talking about the same bucking that I get with my LS in my 2000, this is only on the tightest corners. There is no "bind" otherwise.

Evildriver-3 said:
over inflated tires, syn oil, light wheels.
These things have nothing to do with the subject. If a LS is going to affect mileage (which I say it won't), it would do it regarless of the PSI of tires, type of oil or weight of wheels.
 
#16 ·
    A diff that powers both wheels will be affected by air psi in the tires not being equal it will have steering effects,  nothing hardcore, but it will have steering effects as in drag...if you can't notice it then there are all kinds of slop in the driveline absorbing it..further effecting mpg..which would be something that is highly possible
 
#17 ·
I can't speak for the original poster, but my tires psi is always the equal in the rear, I would not assume his is otherwise.

As much as I hate to hijack, I must.  :-\

You have an aftermarket OD unit right? I assume it is mouted behind the t-case? If so, do you compensate for speedo error when calculating your mileage?

I still find your mileage claims hard to believe, I'm not saying you are lying, but 20 mpg is still hard to swallow. My much more aerodynamic, lighter, OD equipped, synthetic oil everywhere, 31" tires, 3.92 gears, fuel injected 2000 1/2 ton at best got about 14.5 when new, all highway miles. Now, it gets about 12.5 highway/city driving.
 
#18 ·
  My mileage is calculated  the same way....the miles are counted at the rear of the tail housing which is correct and has nothing to do with the splitter, you have an auto also which takes away from mpg unless it's locked as for the tc which helps.
 
 
#20 ·
Yes,  but it doesn't matter if it's the tail housing of the splitter or the t-case or the trans it's still only calculating the tires and gears to the speed of the driveshaft, the splitter has no effect on anything past it.
 
#21 ·
I don't know anything about your splitter, so I must ask, where is it mounted, after the t-case?

Just for arguments sake...
If it is after the t-case, and if your speedo was still hooked to the t-case (which I now know it is not), then the speedo would NOT be accurate.
 
#22 ·
  The splitter slows everything down before it,  t-case, trans, motor..    The splitters tailhousing has it's own speed gearing
 
#23 ·
Geeze you're vaque. How about yes or no. Is the splitter after the t-case?

Based on your response, it sounds like it most likely is after the t-case, in which (as I said before) if the speedo was hooked to the t-case, it would NOT be accurate.
 
#24 ·
  If the splitter slows everthing down but the driveshaft where would it be...it can't be between anything...i even said it slows the t-case, trans, motor. 
 
#25 ·
KThaxton said:
Based on your response, it sounds like it most likely is after the t-case, in which (as I said before) if the speedo was hooked to the t-case, it would NOT be accurate.
Alrighty then, I stand by my above statement, a speedo connected to the t-case would not be accurate.

Evildriver-3 said:
Yes, but it doesn't matter if it's the tail housing of the splitter or the t-case or the trans it's still only calculating the tires and gears to the speed of the driveshaft, the splitter has no effect on anything past it.
Tell me how a change in ratio occurring after where the speedo is connected would not affect speedo accuracy?
Me thinks this is why they put a speedo connection in your splitter, it would not be accurate otherwise.

Ram10, again, my apologies for the continued hijack. ;)
 
#26 ·
  What change....where is your speedo calculated from.....driveshaft speed...just like mine..just like everyones,  except for some newer vehicles that calculate it from the computer and trans gear x rpm...again the speedo is reading shaft speed and nothing else...the splitter and everything before it is the only thing changing...the speedo is not before or in the splitter,  it is only reading shaft speed from the what the tires are making the rear spin it at 
 
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