Gas Milage?

[matt w]

Ok I am running 33's on my 73. It has a stock 302 and an automatic trans. It seems to run just fine. I went 225 miles on Saturday at Freeway speeds 65-70 mph and did about 3 hours of very mild wheeling in the desert.

I have not done a gear change and honstly at hwy speed it does not seem to need the gear change. although I might like to do a transfer case gear reduction at some point for wheeling.

I got exactly 9 mpg. Is that about as good as it gets? Can I do anything besides going to smaller tires (NOT!;D ) to get an added 2-3 mpg?

Thanks for any input

 

[jboomer]

I've got the equivalent of like 31's and a 3 speed and average 10 in mine. I can't imagine trying to get mine up to 70! It's scary enough at 55.

 

[jakesdog]

I have not had a Bronco for quite a while, but your mpg sounds about right for a V8 with a 3spd auto. You have to remember that using 4x4, or just following trails for 3 hours uses up quite a bit of fuel, even if you are just going slow. I know guys with diesel pickups that have complained about their mpg, and I have to remind them of how much they let their trucks just idle to keep the interior warm in the winter, or cold in the summer.
Check it again with more hwy and street miles and I bet it will be a bit higher.

 

[Tito]

If you slow it down to 55-60 (good luck on the hiway) you will likely add a couple too.

 

[thegreatjustino]

If you want better gas mileage at highway speeds, you need to put on larger tires, not smaller.

 

[01JLH]

Larger tires do slow the speedo down and likewise reduces the milage shown from actual traveled. You might want to get your speedometer re-calibrated. If you look in JBG catalog you can see a chart that will give you some idea of what percentage your speedo is off. Milage may be better than you think.

 

[73stallion]

i'd be lucky to get 12 out of mine with 33's, 4.111's, and a 5 speed. ya just can't mileage out of a brick.

 

[garberz]

I'll agree with Tito. You'll have to slow down on the highway if you want better mileage. Make sure your air filter is clean. Timing is advanced to its potential. You should get 12-15 mpg at 60mph.

 

[crankman]

Matt you should be getting a little better than 9, i wonder if your speedo is off, im running 33's with 3.50 gears with a slightly warm 302 w/ 4 barrel and i get 13.8 per mile. I would get a handheld GPS and fill your truck up and next trip keep a good log and then fill it back up and do the math. i bet your getting more than you think.

 

[68ford]

i seem to get get 15 on the freeway all the time keeping at at 60. thats with 35s 410 and a c4. very camed up 302, but high compression and advanced timing. very little throttle to go 60mph.

one trip to the dunes i got exacly 20 mpg, i went 210miles per gps and the tank took 10gallons. 285 76 16s aired to 50psi stock 302 with just rebuilt holley, 410s and c4. timing was advanced to where i had to run premium fuel and i only went 55 in front of a motorhome. same set up would average 15 going to and from school and work.

check and advance your timing, made all the difference for me.

 

[ManTruck]

I have my timing advanced and with a exact mile known I will get 15 to 17 60 miles an hour. My son in the Bronco behind my Dodge going elk hunting.

I am running a warmed up 302 and a two barrel factory carb.
Made me happy because I had not checked it for a long time. It was 130 + miles with a small mountain pass.

 

[doug boykin]

Consistant 12 mpg 36 mi round trip to work and back I live at 7500 ft. elev. 12 1/2 mpg 70 mph to Moab and back loaded with camping gear and a basket in the receiver and two mtb bikes on the back. Mine has a 408 Stroker with Dart heads K.B. pistons 501 lift crower Hot cam ,Rhodes lifters, Edelbrock RPM manifold, 750cfm edelbrock a c4 and 35in MTR's and 411 gears.

 

[commoncold]

I can't imagine trying to get mine up to 70! It's scary enough at 55.

I'll agree with that 100% LOL ;D

With 35" tires, 351W, 5.5" lift, 3.50 gears I'm still doing a solid 12-14 around town. Then again almost every part in the engine is either new or recently rebuilt. Plus the tire/gearing combo makes easy work for the engine at the 50 mph range.

I can guarantee a fuel additive will help. I know quaker state makes a very good brand of it that cleans the engine while it increases octane. Maybe look into changing spark plugs and all that general maintenance stuff too...it really will help

Good luck

 

[blubuckaroo]

The easiest way to get great milage is to lie about it.

 

[nik]

The easiest way to get great milage is to lie about it.

hahaha yup so when the people driving clown cars ask you how much you get you make them feel stupid. oh yea I get 17 around town....

 

[broncnaz]

Ditto blubuckaroos comment

Seriously you should be able to eek out 12mpg at the very least but you cant really calculate max mileage when light wheeling is involved as it will lower your numbers especailly with your curent gearing mismatch.
Still to gain some mileage you need a camshaft matched to your setup and at the very least a free flowing exhaust headers preferred but at least replace the stock exhuast pipes with the next size up it will do a lot. You should also look at your jetting and timing advance there are gains to be made there as well.

I run 33's, 3.50 gears, a NP435, 2.5in lift and slightly built 302 and get 13-15 at 75mph dont drive 55 much but usually pull 14-16 when I do.

 

[phred]

I run 33's 4:10's a c4 and balanced 302. Averages about 12.5 on highway (around 60-65 mph) and 8mpg around town.

 

[matt w]

Larger tires do slow the speedo down and likewise reduces the milage shown from actual traveled. You might want to get your speedometer re-calibrated. If you look in JBG catalog you can see a chart that will give you some idea of what percentage your speedo is off. Milage may be better than you think.

I used my GPS that day for total miles driven, not my speedometer. So I know the miles were accurate. ;D

Oh well, other than the 9mpg the truck performs just fine for my needs.;D

Thanks to all for all the input, suggestions and ideas!

 

[matt w]

Matt you should be getting a little better than 9, i wonder if your speedo is off, im running 33's with 3.50 gears with a slightly warm 302 w/ 4 barrel and i get 13.8 per mile. I would get a handheld GPS and fill your truck up and next trip keep a good log and then fill it back up and do the math. i bet your getting more than you think.

Ya. I used my handheld, (Garmin Rino 120! heh-heh)...I will do this again on the next run;D %)

 

[DonsBolt]

What tires and wheels do you have???????????

Heavy wheels and tires = bad, also agressive mud terrain tires = bad

Off road weight isn't a real concer, but on the street any weight you can get rid off will help your fuel mileage

If your running heavy steel wheels, and agressive off road tires that will really hurt your millage. Switching to lighter alluminum wheels, and all terrain tires will help improve fuel millage. In my case going from all terrain tires to 13lbs heavier mudd terrain tires hurt my fuel millage.

Here are some weights of 35 inch tires just for a little comparison
BFG all terrain-53lbs
Dick Cepek Fun Country-64lbs
Cooper STT-67lbs
Mickey Thompson MTZ-66lbs

So by going from say a MT MTZ to the same size BFG all terrain you loose 13lbs of rotating weight your truck has to push, also the tread design off the BFG All Terrain tires has less rolling resistance. Also if you go from heavt steel wheels to lighter alluminum wheels, you can get rid of another 10 or more pounds or rotating weight.

So depending on what wheels/tires you have??? you can easally get rid of over 100 pounds of rotating weight in just the wheels and tires which will really help improve your fuel millage.