Get better mpg?

[Blu3Rang3r]

Alright,I have a 4.0 ohv 4x4 ranger.The truck has 4.10s and 245/75/16 tires.I get at best 18mpg..at best.It has a fresh tune up,new plugs,new wires,etc and the truck only has 84,xxx miles.If I got the scremin demon( i think thats what the aftermarket coil is called) and change gears from 4.10s to 3.73s with a custom tune what could I expect mpg wise? Not really looking for performance,but its sad when my 07 f250 4x4 gets better fuel economy.

 

[adsm08]

Eh, that seems to be about what the average person gets out of a pushrod 4.0. What's worse is the SOHC's do worse.

 

[notaprob]

On the highway I got 19.5mpg going 70mph. (4x4 single cab long bed with no load 3.73 gears) That is the best I have ever gotten. 17mpg is the usual around town.

this may help also http://www.therangerstation.com/forums/showthread.php?t=107334

 

[Blu3Rang3r]

So 19.5 with 3.73s...i think if i get it tuned I can pull off 21mpg,has anyone had their 4.0 ohv tuned? if so what did you pick up mileage wise?

 

[ronclark]

My 4.0 is around 19.5 to 20 mpg freeway. i am equipped with 30's and 4.10 5 speed.
i keep my speed around 60 mph, if i do 75 i am around 17 mpg.
From what i have read the 4.0 likes the rpm right around 2600 rpm cruising.
gearing up might hurt more than it helps if the engine is working harder.
I know is sucks, but its a 4x4 truck with no aerodynamics

 

[Blu3Rang3r]

Asked around and was told to expect 300-400$ on a diff gear change through a good mechanic(i am very mechanically inclined,but i dont think im good enough to do diff shimming).Then by the time you get a limited slip diff(mostly for winter,I dont really do any off-roading and the 1 tire fire gets annoying during the winter) and the 3.73's im in it for about $1300.I can buy a 4 cylinder car for that.Man this truck just needs to sell

 

[TheBobmanNH]

but its sad when my 07 f250 4x4 gets better fuel economy.

Technology my man. It may not seem like it but we have come at least a little bit forward in the past 15 years

 

[kimcrwbr1]

You can probably do it yourself for around $700 unless you change the carriers also but you will not improve mileage because you will have to press the skinny pedal harder to get it going and keep it going. The 3.73 with 15 inch tires would possibly improve mileage but for a 4X4 you need to match front and rear ratios.

 

[mitch4x4]

I have a 08 auto with 3:73's and with the stock 255 75 16 tires I got 18-19 in town and 23 on the highway all day long. Those days are now gone with the bigger tires, but I can still pull off 18-19. 4:10's are not helping your mileage any no matter what anyone says.

 

[Blu3Rang3r]

So let me get this straight,if I change the rear diff gears to 3.73's I also have to do the front? even though I only use 4wd when there is snow/ice on the ground?Thanks.

 

[ronclark]

So let me get this straight,if I change the rear diff gears to 3.73's I also have to do the front? even though I only use 4wd when there is snow/ice on the ground?Thanks.

Pretty much, if your rear is 3.75 and your front is 4.10, your front wheels will be about 10% slower than your back tires.
If you hit some pavement or high traction surface i would say good bye to the transfer case and what ever else breaks

 

[adsm08]

If you are trying to sell the truck why are you so worried about re-gearing and adding limited slip and all that?

Why not just park it next to the road with a for sale sign and drive the other truck?

 

[Blu3Rang3r]

Alright thanks.And basically I was taking in consideration that if I were to re-gear it and get it tuned if I could squeeze off low 20's mpg that I would keep it.

 

[adsm08]

Ah.