Best swap for good mpg??

[Unregistered]

Which engine that can be put in a bronco has the best MPG?

 

[g_money]

Fuel injected 5.0 will drop right in.

 

[Nuke]

Its not just the engine, you must consider the whole drivetrain. The ZF5 Transmission seems to get the best MPG. I'm not sure what the best final gear ratio is, but it will be dependant on you tire size which in itself will effect the gas milage. Also, some claim 5.8 (351 W FI) has better gas milage for EBs. This is what I have gathered because I want to know also. I holding out for Ford's new diesel that is going into the 04 F150 and hope that it will be "simple" to put in an EB.

 

[76Broncofromhell]

I got 10 mpg with a mild 302, I get 10 mpg with a HOT 408 Windsor. If you're lifted, you're probably not going much over 12. But don't feel bad, a 2003 EFI F-150 with 35's gets about 12. You can save yourself about $20,000 with a faster Bronco

 

[SteveL]

you could swap in a 3 cyl out of a metro to save on gas but you might have to push it to get going. You will get close to the same with any small block ford v-8. If you go 289 or 302 you will be pouring more gas in it to do what a 351w does at lower rpm. Anything you do I would guess you will get about 10-12 mpg.

 

[Broncobowsher]

I have a '93 escort wagon with a 5 speed that gets high 30 MPG range. I'll trade you.

 

[bpatton74]

I've heard of guy's with a FI 302, AOD, 4.56 gears, and 35in tires get up to about 17mpg. But like I said that is only what I've heard.

 

[Rustytruck]

My 74 Bronco origional engine at 89,000 miles gets a peak 15 on the highway 10 around town and 10 off road with an automatic. There are definate patterns to drive and changes that have to be made and conncessions that have to be dealt with. I run a quadrajet which upped my off road miles from 6-8 to 10 and my street milage from 8 to 10. and also let my peak mileage at 15 go from 55mph to 60 mph over my stock 2 barrel. My milage was not just from my speedo but also verfied by my gps. so milage may be a little off but is extremely close. I run 4:11 gears and 33 inch tires and the truck stripped of doors and hard top and I have a 2 inch lift. The motor is also changed by running a timing chain set 4 degrees advanced and dual exhaust with crossover pipe. and I run distributer advanced at 12 degrees. Quadrajet carb on mustang cast iron 4-barrel and a 14 inch open element air cleaner. I also run Cheverons middle pump gas. reality driving day to day drops about 1-1/2 mpg but good numbers can be achieved if you are dilligent and keep the engine at the peak of the power band when crusing (3000 rpm). The torque to weight ratio in the Bronco sucks with a stock engine not counting the high profile wind issues.

 

[ABurns]

A friend of mine has an injected 408 stroker w/NV4500, 4:56's and 36's. He says he can get 16-17 if he keeps his foot out of it.

 

[wildbill]

%) %) %) If you have a lot of money you can order a 4 cly. perkins diesel w/turbo to fit your bellhouseing and some new front springs and some trick gearing and you should be good for about 25+ mpg. %) %) %) Bill %) 8)

 

[72bronco]

I didn't buy a bronco to get good mileage. I get about 11 mpg both city and highway. In fact, I could push my bronco off a cliff and it would still only get 11 mpg on the way down.

 

[th45cruzr]

With a 170ci six cylinder, a three speed, 4.11's and stock height tires i would get 16-20 mpg in my '66 Halfcab. It was a fairly modified six though. It had hooker headers, a holley 300, custom ground cam (with a fair bit of lope), and 9.5:1 compression. I don't know what mpg it got in stock form.

 

[Nuke]

There are a few people here who claim 16-20 MPG with a ZF5.

 

[ASE-73]

The Bronco is like a barn door going down the road. Aerodynamics (or lack thereof) is the issue.

If 2-MPG (best case) is worth the effort, then go for it ... but do not expect significant gains with any configuration.

 

[swa0330]

A package that is guaranteed to give you 25 city and 30 highway with 35's and 4.10 gears with an NV 4500 is the 4BT cummins or 4BDT Isuzu. That's one reason why I am swapping in the 4BT. The 300+ ft lbs of torque at 1300 rpm is the other reason. If you aren't up for all that, then I suggest a fuel injected 5.0 with a 25-30% overdrive tranny. I don't care what BS anyone says, without an overdrive tranny you won't get above 14mpg even with stock bronco tires. Maybe if you turn the engine off and coast down a mountain pass. If you want details on the 4BT swap I can tell you most everything you need to know. I am starting the process soon, and my buddies who did the swap said that it is about the easiest engine swap you can do. The engine only needs 1 wire to work. That's it.

 

[ASE-73]

A package that is guaranteed to give you 25 city and 30 highway with 35's and 4.10 gears with an NV 4500 is the 4BT cummins or 4BDT Isuzu. That's one reason why I am swapping in the 4BT. The 300+ ft lbs of torque at 1300 rpm is the other reason. If you aren't up for all that, then I suggest a fuel injected 5.0 with a 25-30% overdrive tranny. I don't care what BS anyone says, without an overdrive tranny you won't get above 14mpg even with stock bronco tires. Maybe if you turn the engine off and coast down a mountain pass. If you want details on the 4BT swap I can tell you most everything you need to know. I am starting the process soon, and my buddies who did the swap said that it is about the easiest engine swap you can do. The engine only needs 1 wire to work. That's it.

Now that will work ;D

 

[rjlougee]

Aside from the drivetrain, you have to consider how you've got the rig set up, i. e. hard, soft or no top? Doors and/or tailgate? Size of tires, aluminum or steel rims, etc... There are a lot of variables. I average about 15.5 in the summer in mine, at 7,000' elevation with 85 octane gas, no top or doors, etc... In the winter with everything on there it gets about 16.5. Best ever was a long highway trip in the flatlands, where I averaged a little over 19.

So on to recommendations:
1. A MAF SEFI 351W is about the best you can do for the engine. A good stroker would do a little better; however, most guys driving strokers can't stay out of it.
2. Good OD tranny, either ZF, AOD or 700R4.
3. Aluminum rims with a narrow footprint. I run 35x12.5 MTRs on 8.5" aluminum rims. Every pound of weight at the wheels is like adding 10 pounds inside the vehicle. 10 pounds at each wheel is like carrying an extra engine around in the back.
4. Use good gas. Try several different stations around you and see which give the best mileage. One place near me uses really crappy gas, but it's cheap. The better gas at the station across the street will give me about 35 miles more per tank, so, depending on the price at each one, the more expensive gas is actually cheaper to drive.
5. Synthetic oils/fluids will also usually help.
6. Reduce your friction points in the drivetrain, i. e. make sure pads/shoes aren't dragging, etc...
Joe

 

[Nuke]

A package that is guaranteed to give you 25 city and 30 highway with 35's and 4.10 gears with an NV 4500 is the 4BT cummins or 4BDT Isuzu. That's one reason why I am swapping in the 4BT.

Where are you getting a 4BT? How hard is the conversion? How much?

 

[Unregistered]

please email me at paint669@aol.com and please tell me more about how to do this swap. thanks

 

[swa0330]

Where are you getting a 4BT? How hard is the conversion? How much?

I am sort of doing it as a two stage process with the engine. I am buying a core off a guy and building the engine mounts and crossmember. Then I am redoing the whole body and getting the bronco set up. When I have everything done, I am going to trade the core in for a re-man engine.

The cost of the engine with a tranny (usually SM 465) is about 2500. That's going to be a used one from a bread truck with about 100K miles or less. It's not a mileage that should scare you though, as these things never die. When you look at the price it is pretty good considering that you are getting a torque monster that is injected.

As far as what is involved, you will need to probably fabricate motor mounts and a new transfer case crossmember. The Driveshafts will probably have to be lengthened or shortened. The other thing is that you will need a minimum of 2 inches of body lift and 3.5 + inches of suspension lift, as this engine is taller than the 302. The wiring is retardedly simple. One wire runs the whole engine (fuel pump shutoff solenoid).

It sounds complex, but the guys who I am working with that have done this conversion say that it is probably the easiest swap you can do. I would say that to do the whole conversion, may run about $5K if you are handy and re-use a lot of stuff that is on the bronco. It is definitely the best way to get killer torque on the trail while getting the fuel mileage of an escort on the road. You will need an overdrive tranny if you don't want to trailer the thing everywhere, as the redline is 2500 rpm (it's not a good one for the dunes). The NV 4500 from the dodge diesels will bolt up right behind it. After that, you can use either an NP 205 or the NVG 241 that comes in the 2500 rams. My e-mail is in my profile. We can talk over the phone if you want more specific answers. As you can see I have already written a lot, and that isn't even half of the full story.