Mileage Quest 2011!

[fomocoguy]

Well, I've had it. I'm tired of it, and I won't take it any longer. It's been bothering me for years now and I'm finally ready to do something about it. Yes, I am talking about the same problem that many of us face with our full size FE powered trucks. I am talking about single digit gas mileage.

This thread is going to be an on going long term project that any one of you can duplicate and hopefully learn from so that you can take some of the same steps I do and get positive results in your fuel mileage. Let me tell you where it began...

Two weeks ago my truck was running very rough. It never has got any better than about 9 mpg, but the last tank before any repairs got 6mpg. After some diagnosis I found a seriously worn distributor and promptly replaced it. With the new distributor in place and timing set at 8* btdc I went for a test drive. Even with it running well and smooth, it once again got 6 mpg!

So, why only 8* advance is probably what some of you are thinking. Well, my old 360 has always rattled a bit with any more advance than that. On a whim I decided to go ahead and bump the timing up with the new distributor, all the way up to 12* advance at idle. Well, low and behold, the next test drive showed an astonishing 15 mpg, with no engine rattle! The old distributor must have been advancing way to much and causing the pinging. Fantastic results to say the least!

This brings us to my project. After seeing that double digits are possible, I am on a mission to squeeze all the mileage out of my truck that I can. Tomorrow I will adjust my tires to full inflation and make another run to get an accurate baseline mpg. I will fill her up at the same fuel station and the same pump and will make a dedicated highway run that will be my testing grounds for the rest of this process.

Here is the baseline info for my truck: 1969 F250 Crew 4x4
360 V8, 2 barrel, headers, Spintech mufflers with full 2.25" duals and h-pipe
4 speed trans
Dana 24 t-case
Dana 60 rear with 4.11:1 gear ratio
33x12.50 mud terrain tires

The truck is tuned perfectly, with a recent tune up and correct point gap and dwell. The carb was rebuilt and was tuned with a vacuum gauge. I made sure that every aspect of the engine was in good tune before beginning so that only the changes I'm about to make will effect the mileage.

SO, the first mod will be all synthetic fluids. I will fill the rear end with 75w90 fully synthetic gear oil and plan on using fully synthetic 50wt oil in the t-case and trans. I will change the engine oil for most likly mobil 1 full synthetic. Afterwards I will make another run and post my findings.


The next mods will include an electric fan install, a true cold air intake, and possible cam and tire changes. ANY ADVICE FOR FUTURE MODS WILL BE GREATLY APPRIECIATED!

Hopefully this wil become a helpful thread to all of us who seem to be spending more and more on fuel costs these days but can't afford or don't want a diesel swap.

Last, to the moderators: I wasn't sure where to post this, so if you deem it inappropriate for the general discussion area and need to move it I fully understand. Thanks!

[1971ford]

I'll be watching this thread closely
For the air intake what are you running now, a little 2-3" or stock? I'd either get a 5" (what i'm running" or get a stock and put asecond tunnel on it and run tunnel ducts to the grill for cold air.
Make sure your choke is adjusted just right so you dont lose milage by revving too much in the cold.
I'd check all the brakes too, make sure they are adjusted correctly. If one was adjusted so it rubbed just a tad I think that would cause a slight drop.

Depending on how far you want to go you could make a air dam under the bumper. It might look ugly and who knows if it would even save a noticeable amount
Baldwin TT runs one
http://image.trucktrend.com/f/32240622+ ... -truck.jpg

You have west coast mirrors don't you? I have them too and i just know that they are the most terribly aerodynamic things you could put on your truck. Consider a smaller mirror although on a crew long bed this might not be worth it.

I also just read on here that someone had their exhaust tips cut at an angle so the air next to the truck pulled exhaust out, supposedly for another MPG or so. I'm not sure where your exhaust exits though.

I'm sure you know this but driving style is the biggest factor, i'm probably the slowest driver out there (i take my sweet time getting my highboy/390 up to speed to save gas). And I cost a good 1/4 mile at times if i see a stop sign up ahead, or if there is a red light far up ahead I'll cost a long ways so by the time i get to the light it iwll be green and i can stay off the brake pedal.

[fuzzier1]

I rented a 26' U-Haul the second week of January this year and it had a vacum gauge hooked up to it that had green and red zones on it that showed "best mileage" and "worst mileage". You romp on it and it would go into the red zone or if you took it easy you could keep it in the green "best mileage" zone for the most part. I bet someone makes a kit that has the red and green zones or best worst zones what have you. Or you could even just get a vacum gauge and try to keep as much vacum as possible on it while driving. I was amazed how much I watched it and kept my foot out of it. Might help you not romp on it too much.

Fuzz

[fomocoguy]

I'll be watching this thread closely
For the air intake what are you running now, a little 2-3" or stock?

Right now it hasthe factory air cleaner housing with the choke stove wired open.

I'd either get a 5" (what i'm running" or get a stock and put asecond tunnel on it and run tunnel ducts to the grill for cold air.

That is the plan. I also want to be sure the tunnels/tunnel are well insulated so that it doesn't soak in much engine heat.

Make sure your choke is adjusted just right so you dont lose milage by revving too much in the cold.

She's got a properly adjusted manual choke, so she's good to go!

I'd check all the brakes too, make sure they are adjusted correctly. If one was adjusted so it rubbed just a tad I think that would cause a slight drop.

It's been some time since I adjusted the brakes and I know the adjusters aren't working that great, so if anything they are probably a bit loose.
The air dam is an interesting idea! I'll jot it down on the idea list for sure.
I love my west coast mirrors, so I'll just have to coat them in teflon for less resistance. I have rear exit exhaust.

As for driving style, you are absolutely correct. However I'd like to just try and drive as I usually do so I can get an accurate idea of where I was and where I'm at. I've tried that before and I usually drive with mileage in mind for awhile and then slowly revert back to the way I usually drive without even realizing it. I don't hot rod it anyway; there's no point when you have 200hp trying to pull around 5600 lbs....

[fomocoguy]

I rented a 26' U-Haul the second week of January this year and it had a vacum gauge hooked up to it that had green and red zones on it that showed "best mileage" and "worst mileage". You romp on it and it would go into the red zone or if you took it easy you could keep it in the green "best mileage" zone for the most part. I bet someone makes a kit that has the red and green zones or best worst zones what have you. Or you could even just get a vacum gauge and try to keep as much vacum as possible on it while driving. I was amazed how much I watched it and kept my foot out of it. Might help you not romp on it too much.

Fuzz

I think a mileage-o-meter would be a great idea! That's something that I would always be concious of and probably try and make a game of it. For whatever reason I hadn't really thought of that. Thanks!



Great ideas guys; keep em' comin'!

[hazelnut]

Ive got a 69 highboy and im thinking about putting a airdam from a newer truck under the front bumper to divert the air around the truck instead of it going under it, Dont know if thats going to help with mileage or not but i thought i would throw it out there for you to see if you wanted to give it a try. What RPM do you turn driveing 60 mph ? I havent had my highboy on the road since i bought it because it was rusted out bad so i cant say what ive tryed, only what i think might help

[fomocoguy]

Ive got a 69 highboy and im thinking about putting a airdam from a newer truck under the front bumper to divert the air around the truck instead of it going under it, Dont know if thats going to help with mileage or not but i thought i would throw it out there for you to see if you wanted to give it a try. What RPM do you turn driveing 60 mph ? I havent had my highboy on the road since i bought it because it was rusted out bad so i cant say what ive tryed, only what i think might help

I think I'm running about 2800 rpms at 60 with the 33" tire. One idea for the future would be 35" tires to cut down on a few rpms, but I don't know if it will help anything. The higher rolling mass may hurt. Then again I would go to an all terrain, so the less aggressive tread pattern may help. I have a feeling that mod may be a wash...

[1971ford]

yeah , i keep going back and forth about whether a 35 or 33 would be better on fuel for me.
35 lowers the RPM's therefore better but probably an inch wider tread than a 33 i'd run, and more weight. I think swapping tires wouldn't be worth it.

I bet a fiberglass drop center or pie cut hood would help. The front of our hood is pretty tall and a couple inches of it pushes air down into the core support
I've also seen 3 2" holes cut in the side of the back of the hood to let air escape the big engine compartment parrachute.
Or maybe some of these super cool stick on vents would do the truck at autozone
But how far do you want to go?

[BobbyFord]

"Good" gas mileage will never happen with 4:11's in a 4WD Bump.

[Brokenarrow]

"Good" gas mileage will never happen with 4:11's in a 4WD Bump.

Exactly what I was thinking. If you want good mileage from a 3/4 ton 4wd you gotta go diesel.

[fomocoguy]

"Good" gas mileage will never happen with 4:11's in a 4WD Bump.

"Good" gas mileage will never happen with 4:11's in a 4WD Bump.

Exactly what I was thinking. If you want good mileage from a 3/4 ton 4wd you gotta go diesel.

Well, I suppose we should set a definition for "good" if you'd like to make a statement like that. For me, I believe that 15 mpg would be good for an FE powered 3/4 ton 4x4. I am realistic and don't expect to see 20 mpg, but 15 mpg beats single digits any day of the week. I am through with single digits.

[fomocoguy]

Today I made my first run to set a baseline mpg for me to work off of. Knowing that I would never get accurate numbers from my gauges I picked up a garmin GPS yesterday at Best Buy (what a cool little contraption!!). I'm happy I did, because it showed me an indicated 65mph when my speedo says 55, so I'm 10mph slow at the needle. Anyways, I filled up with regular at the gas station next to the highway and headed for the Lowes that is about 25 miles from me, all highway except about a quarter of a mile. With my tires at max pressure (50psi), a strong headwind on the way there, rolling hills but more uphill on the way back, tailgate up, window down, and running between 60 and 65 the entire way these are my findings.

51.6 miles traveled
4.09 gallons used

12.62 MPG.

Pretty respectable in my opinion! I've never got better than 9 before I installed the new distributor so I'm happy with that. I filled up at the same pump, facing the same direction, and squeezed the handle to top it off one time at both fill ups so it should be pretty darn accurate.

So how come I got 15 the other day you ask? Good question! I was hauling some drywall (just a couple sheets) and had the tailgate down that day. I also probably didn't go over 60 and was taking off easier so the drywall wouldn't slide out. Plus I don't know if I topped it off or not, so it may have stopped short when filling. Either way, 12.62 is now my starting point.

Considering my Cherokee weighs 2000lbs less, has a 4.0l FI inline 6, and only gets 15, I'm impressed. If I can get to 16 or 17 I may have a new daily driver.

[BobbyFord]

Well, good luck, I guess anything's better than single digits.

[Mancar1]

Have fun in your quest. I am happy when I get 11 - 12 on my 68. When I get around to going with a 4 Bar. I will be happy with 10 MPG.

[fomocoguy]

Thanks! I'm already having fun with it and I haven't even started trying different things yet.