91 ranger,4.10's,33's-what would get better mileage?4.0l or 2.9l?

[canyoncritter]

my 91 4.0L 4x4 5spd lifted 6inches worn out 33 bfg muds and 4.56;s got a avg of 16-17 with mixed driving.But I also have a herman munster foot.

on the one long hwy only trip i took with it, I got 19 with the tach sitting at 3,000(like I said I have a herman munster foot)and I used my gps for actual millage.As I know my spedo is off.
this truck has 150,000 miles on it.

Had a 88 2wd bone stock with the 2.9 and 5spd.if i rember right it had 3.45's and 205's on it. Used this truck when I use to have a pool service.So I always had a load in it...aprx 40 gallons of chlorine,50lbs of tabs and anouter 50 lbs or so of misc stuff.got about 14mpg lots of stop and go.

93 4x4 4.0L 5spd bone stock,with 3.73;s and 235's..same load as above got a avg of 16...took this one on alot of hiway only trips again. avg speed 75-80 and I could get right at 20

87 2wd 2.3 5spd 31's and 4.56's 20 no matter what I did.just a gutless wonder that was a timex.I beat the crap out of this truck.


I say go with the 4.0L.....just a word of advice really look in to mixing and matching computers.as you can burn things up. 4.0L coumpters and wiring harness are not generic...ford swaped crap around.just do some reading around.

 

[Hahnsb2]

Go with the 4.0. No matter how I drive my 2.9 it gets shit milage (15MPG) since the larger tires even though I'm properly geared. I know a 4.0 would get better milage in my rig,

 

[ArcticRaiders]

Please look up BSFC.

This makes no sense.

If you generate more horsepower, you burn more fuel, in direct proportion. Unless you don't know how to drive and you lug the engine.

I can see see why you say what you say. But if you understand the powerband of an engine and their pulling capacity, then you would understand what I said. Going up hills a truck that has more torque is likely to get better mpg in conditions. The 4.0l has more torque so the engine doesn't have to work as hard therefore using less fuel. The 2.9l requires more fuel to push a truck up a decent size hill than the 4.0l does. Living in the Rocky Mountains I have first hand experience with this.

 

[holyford86]

Go with the 4.0. No matter how I drive my 2.9 it gets shit milage (15MPG) since the larger tires even though I'm properly geared. I know a 4.0 would get better milage in my rig,

From the look of your signature the setup I have is very similar to yours and I'm getting 19-21 mpg mixed mileage. Interesting how there can be this much of a difference.

 

[Fordmandan]

I drove my stock 2WD 4.0 with the hammer down constantly, and it would consistently get 17-18mpg in town.

-dan

 

[Hahnsb2]

From the look of your signature the setup I have is very similar to yours and I'm getting 19-21 mpg mixed mileage. Interesting how there can be this much of a difference.

I rarely drive freeway but I don't drive straight town either, 65% country roads, 30% town and 5% freeway probably. I dunno how much your rig weighs but I weighed mine a few months ago and its 4000LBS with me in it.

 

[MAKG]

I can see see why you say what you say. But if you understand the powerband of an engine and their pulling capacity, then you would understand what I said. Going up hills a truck that has more torque is likely to get better mpg in conditions. The 4.0l has more torque so the engine doesn't have to work as hard therefore using less fuel. The 2.9l requires more fuel to push a truck up a decent size hill than the 4.0l does. Living in the Rocky Mountains I have first hand experience with this.

Then explain how I managed to get 22 MPG uphill over I-70 in Colorado, with a 2.9L.

Keep the engine in the powerband and in proper repair and you WILL consume 0.5 lb/hr/HP. At highway speed, virtually all the cruise power is due to external conditions, mostly wind and gravity. It doesn't matter what engine you have. You don't get CLOSE to the limits of a 2.9L at highway speed when properly driven, even approaching the Eisenhower Tunnel.

 

[rickcdewitt]

What did you get (miles per gallon) with the 2.9L. I'm running a 4.0L in my ranger and I get about 16 mpg in the winter (Michigan). 16 mpg driving it like a normal person (at $3.15 a gallon, I know its probably more in other places, I'm gonna take it easy) If your really gonna dig into it all the time its not going to be forgiving on your wallet.

i was getting about 15.5-17mpg depending on how i drive,when it was stock i was getting 19-20mpg(not in the greatest state of tune).i do kind of like the 2.9l because i can wheel for almost a business week at camp with short trips and extended idling and use only about a tank of fuel.

 

[rickcdewitt]

I rarely drive freeway but I don't drive straight town either, 65% country roads, 30% town and 5% freeway probably. I dunno how much your rig weighs but I weighed mine a few months ago and its 4000LBS with me in it.

sounds like where i live.just looking at the trucks you might think the b2 is lighter than a ranger long bed.i think when i had my truck weighed it was 3300-3400lbs.i should have stopped at 31's or 32's with the 4.10's but the 33's fit(sawzall)and 33's and 4.10's makes the speedo accurate within 1 mph again(same as 3.55's and 235/75's).

 

[MAKG]

A Bronco II has a lot of sheet metal and windows in back that a Ranger doesn't have. Mine was close to 4000 lbs normally loaded as well when I had it.

 

[rickcdewitt]

Then explain how I managed to get 22 MPG uphill over I-70 in Colorado, with a 2.9L.

Keep the engine in the powerband and in proper repair and you WILL consume 0.5 lb/hr/HP. You don't get CLOSE to the limits of a 2.9L at highway speed when properly driven, even approaching the Eisenhower Tunnel.

i think i just need to take a trip down south and pay you or junkie to tune my 2.9l when its rebuilt,although i don't know if i believe his claims (what did he say?24-26?) with 35's!my truck always had a slight miss at idle since i got it though and had 198,000 on the clock when i drowned her,so it was hardly in opimum tune.

 

[MAKG]

I'm half as far from you as Junkie, but I didn't tune that 2.9L. I kept it in top repair and got rather anal about the charging system and computer grounds. The only thing in that engine that wasn't standard issue was Mobil 1 10W-30. That can't account for the mileage (that's not why it was there).

It did have a stick; that can make a difference. And 3.73 gears. Tires were bigger than normal, but not much (29 inches).

The Exploder gets a virtually constant 19 MPG no matter what I do to it. It has somewhat bigger tires (31 inches), and the rest is all the same except for 3.54 gears. Of course, it's heavier.

2.9Ls like to wind up. I think you understand that with 4.56 gears. The mistake a lot of folks make is to drive it at 1500 RPM, thinking that saves fuel. It makes the engine into a total dog to push it that far below the powerband, and it costs fuel.

 

[AllanD]

From a Physics standpoint, a 2.9L will get slightly better mileage than a 4.0L if both are driven under the same conditions.

This is misleading, screw it, it's blatantly untrue!
Though directly in line with what the government and environmental groups would want you to believe...

Under some specific conditions the 2.9 will do better
under others it's a hopeless task to try.

After driving in excess of 600,000 miles on many different 2.9's
in several different chassis I can say that in "pure highway" driving, relatively unladen at moderate speeds with relatively
small tires (235's) and 4.10 gears that allow the engine to spin at very small throttle openings a 2.9 CAN get mid-20's or better.

so far as I can PROVE by driving I've done myself you can get 26mpg out of a 2.9, but I've managed that exactly TWICE.
More typical is 23.5mpg.

Now hook up a trailer to the truck 2.9 and the mileage drops
into the low teens (13-14 is my experience deadheading my
16ft dovetail car transporter trailer)

Doing the same thing with the 4.0 I switched to in september
and driving back to Pa from Wyoming the truck managed to
get high 17's "tickling" 18mpg.... over 1854miles.

after that many mies I think I can say that it's "realistic"

Same 235-tires, same 4.10 gears same 5sp trans.

Just driving around my semi-highway rural area
I get 21mpg with the 4.0 over a 21gallon tank.
my 2.9 wouldn't do better than 19.5mpg in the
same driving, more typically 18-ish

Hell, last week I averaged 20.5mpg on a 20gal tank and that
included a 193mile round trip to NJ deadheading my tow
dolly going out, and dragging a 2004 Saturn comming back!

I have not yet made a long highway run with my 4.0 to see,
but I suspect I can get >23mpg with it, mabey even 24mpg.

So with a carefully driven under ideal conditions the 4.0 might
not get the ultimate peak mileage that the smaller 2.9 engine
will, but it can easily equal the average.

And as far as I'm concerned the jury is still out on ultimate
mileage over a pure highway trip. I.E. crusie control on
uncongested interstate @65-70mpg.

I'll be sure to let everyone know after I've driven westbound
across Nebraska on my way to Wyoming on or about
the 12th of December.

My goal is to make the 455.32mile distance across Nebraska,
on I-80 on ONE tank of fuel, and to do that I only need to
get 21.68mpg

considering I've managed 21.2mpg in "mixed" driving
with my 4.0 accomplishing this leaves the bar set pretty low....

And then see just how far into Wyoming I can go.
from the Wyoming border to casper is ~180miles I doubt I'll make it but I'm gonna give it a damned good try

How can a 4.0 get better mileage than the smaller 2.9?

Let me tell you a little story... back in the late 1960s Pontiac
conducted a little test... they took several essentially identical
1968 or '69 Tempests and put each of their different V8 engines
in it ranging from the smallest the 326, to the 455.

And they geared each car differently, so that each was capable of approximatly the same acceleration, with the big 455 turning the
tallest gears suprisingly the 4.55 tiurned in the best mileage when a long distasnce test was conducted.

Why? because the big engine simply didn't have to work to keep
the car moving.

Or had to work a lot less hard.

I think the same kind of thing is going on in comparing the 2.9 with the 4.0.

the 4.0 makes as much torque just off idle as a 2.9 is capable of
making at peak.

AD

 

[ArcticRaiders]

Then explain how I managed to get 22 MPG uphill over I-70 in Colorado, with a 2.9L.

Keep the engine in the powerband and in proper repair and you WILL consume 0.5 lb/hr/HP. At highway speed, virtually all the cruise power is due to external conditions, mostly wind and gravity. It doesn't matter what engine you have. You don't get CLOSE to the limits of a 2.9L at highway speed when properly driven, even approaching the Eisenhower Tunnel.

If you notice on I-70 it is more of a constant climb that isn't that steep compared to other places. and doesn't change speed very much.

Also your equation for consumption is wrong. I went ahead and looked at what you said to last time, the BSFC which you are using for your source of what you are really saying. I think you need to go look at that again, and realize that torque is just as much a part of consumption as rpms are.

 

[MAKG]

You aren't understanding.

It's 0.5 lb/hr/HP. That means you burn a FIXED amount of fuel under fixed external conditions. Don't confuse torque with throttle position. You need the SAME torque at the axles to climb the same hill at the same speed and acceleration. You make up for the difference between the two engine's outputs with appropriate gear choice. Not difficult.

Allan's comments are a measure of the detailed shape of the torque curve. Torque curves are not truly flat within the powerband, but they are close for streetable engines. LESS so for carbureted (and to some extent TBI) engines. The only thing fundamental in all this discussion is that bigger engines of similar design weigh more. But it's not enough more to matter; if you care, go on a diet, clean the crap out of the truck, or lose the passenger. 'Cause that's the size of the effect. And it gets swamped by other things like the shape of the intake manifold (especially on carbureted engines).

As for towing the vehicle's weight with a 2.9L, that's well beyond what it was designed for. Get it into "passing mode" and the fuel consumption will go up because the engine changes strategy. This is hardly a fair test for what was asked about.

Allan, you've lived in suburban Pennsylvania far too long if you think the single-tank stunt is a good idea. Running out of fuel in the middle of nowhere can be a LIFE-THREATENING EXPERIENCE, particularly if you run into severe weather. And Jerry cans are a huge problem in a collision. I generally don't let my tank get below half in isolated areas, since it can be 100 miles to the next fuel station. You can try this on I-95 if you really want to.