the infamous gas milage question

[whoad00d]

ok i did the search forums and didn't quite get what i was looking for so here it is. I have a 94 mazda b4000 4x4 with a 4.0 4 inch lift and 32'' tires, and i only get 14.6 on average i do mostly hiway running, but i live in kansas with alot of hills but still i think i should still get about 17, anyone anything everything on the engine exhaust all stock.

 

[Dweano]

What's your gearing? Is it tuned up? Any dragging brakes or anything?

 

[whoad00d]

no brakes are draggin i just did the standard tune up myself a month ago i wanna say 3.83 gears.

 

[joecool85]

no brakes are draggin i just did the standard tune up myself a month ago i wanna say 3.83 gears.

Probably 3.73. You could use a set of 4.10, but 3.73 shouldn't kill your mpg that bad. Are you driving stick or auto?

Auto 4.0s are known to get ~15mpg.

 

[Jay FX4]

That lift is killing your aerodynamics.

 

[Big Jim M]

32" tires killed your vacume.. Your truck is lugging everywhere it goes. Lack of vac keeps the timing retarded to stop clattering. Change back to stock tires or change gearing in the rearend. Guys think tall tires look cool...never giving it a thought as to what is happening to their ride.
Big Jim

 

[whoad00d]

yeah its auto and i mis typed that its the 3.73 gears i understand the hole lift and big tires messing up the areodynamics and everything, if i where to go and do the 4.10 gear ratio how much and i looking and what would be some of the affects of going with the higher gear ratio?

 

[ForOffRoadDriving]

going with taller gears is going to make your truck more peppy and will be easier on your engine. regearing the axle you have in there is going to run around 400 or better, or you could get a junkyard axle with 4.10s installed (need to know what axle you have) or find a genII explorer with 4.10s and disc brakes which would get you better gearing and better brakes to help slow down those 32s.

 

[Big Jim M]

yeah its auto and i mis typed that its the 3.73 gears i understand the hole lift and big tires messing up the areodynamics and everything, if i where to go and do the 4.10 gear ratio how much and i looking and what would be some of the affects of going with the higher gear ratio?

The first thing to do is to MAKE sure which gears you have in there.. 3:07 is a more likely gear for your ride from the factory..
BTW 3:07 is a higher gear than 4:11.. The gear numbers tell how many times the driveshaft turns over compared to the wheels.. The wheels being ONE and the driveshaft being 4:11 times.
So what you need is more driveshaft turns. 4:11 would be a good number for 32" tires.
Jack up one wheel and put the vehicle in neutral.. with a chalk, mark both the tire and the driveshaft.. turn the wheel by hand, zackly ONE TURN.. while counting the turns of the driveshaft. You will find 3:07, 3:54, 3:73, or 4:11 turns and that will be your present gearing. Easy ain't it?
Big JIm

 

[Dweano]

Hey big jim you seem knowledgeable so im going to thread jack a bit (sorry) did a ranger even come with a 4.10 gearing in a D35 in 96? And question two....a 93-97 D35 should work in a 96 right?

 

[BlackBII]

Dweano-
Yes
Yes - Although, they did get twin piston calipers in '95, but if all your changing is the pig, you'll be fine.

Also, watch out for the D28/35 Hybrid:
http://www.therangerstation.com/tech_library/4wd_Front_Axles.html

In my BII with a 4.0, 4.56 gearing and 33"s, I usually get 18-20mpg.

Its you gearing that's killing you.

 

[RotorFX4]

If you jack up the tires and measure like big jim says, make sure you jack up and rotate both rear tires. I may be wrong but I think lifting and rotating only one tire with an open diff may cause the tire to spin twice as fast as the gearing would indicate resulting in some strange ratios like 2/1 or so.

 

[Dweano]

BlackBII...thank you. I was sure that was the case except my junkyard guy said "you cannot swap 4.10's into your 96 from a junker. If you want 4.10's you need an aftermarket ring and pinion" I was sure they came with 4.10's and any third gen pig would work. But i didn't wanna agrue with junkyard man so i just left. Now i think i'll go with 4.56's and hope to increase my mileage. Wierd thing tho...235/75/15 tires and 33x12.50x15 tires...get me the same mileage. I get like the same mileage i did when i bought it stock as i do after i lifted it and put on bigger tires. I'm hoping the 4.56's and 33's combo will get me better mileage that the stock 3.73's and 235/75/15 AND the 33x12.50x15 tires? I have a 4.0 too btw. Sorry to thread jack again but I'm having the same situation.

 

[AllanD]

a Gen3 with 4.10's will usually have a Hybred unless you sumble across
one of the ultra rare R7 coded 4.0 trucks

Though a hybred will work fine in anything other than a 4.0 Ranger
people dislike them for some reason.

Fact is the D28 itself was entirely adequate with any stock gearing
until ford started putting 4.0's in Rangers, what failed was the shaft yokes
But since the hybred D28/35 uses the larger D35 U-joints and Yokes
(which are in point of fact the same U-joint as used on the F-150 D44)
this is a non issue.

To swap in a Hybred you'd need the inners hafts or both sides.

But on your 4.0 truck... the junkyard guy was right, more or less,
He just didn't explain himself well.

I've personally seen many Hybred diffs with 4.10's
To date I've seen exactly ONE 4.0 Gen3 with factory 4.10's

By comparison I've seen atleast a dozen 1990-92 2.3 4x4's with
REAL D35 and 4.10's

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[Big Jim M]

Howdy roto

If you jack up the tires and measure like big jim says, make sure you jack up and rotate both rear tires. I may be wrong but I think lifting and rotating only one tire with an open diff may cause the tire to spin twice as fast as the gearing would indicate resulting in some strange ratios like 2/1 or so.

You sir, are incorrect in your thinking. One tire will do just fine.
Big Jim