Pine Barron

I'm trying to maximize my fuel economy in my F150 4x4. I realize that good mpgs and 4x4 is like an oxymoron, and I know that this subject has been beaten to death, revived, and then beaten to death again; but one thing that isn't commented on much is rolling resistance. I'm thinking about tire size/weight, wheel weight (what is ideal?), adding a lightweight skidplate underneath to cut back on drag. Maybe a modified grille that isn't so gaping? Brake drag? Anybody have any luck in significantly lessening their rolling resistance or thoughts on the matter?

mustangGT90210

If you're trying to reduce your rolling resistance with tires, I hope you don't go offroad.

That being said, there's a site called Ecomodder or something like that that seems to come up in efficiency discussions, you should check it out

Just call me Sean

iTrader: (1)

Make sure your tires are sized properly to the gearing you have. That will help with fuel economy. Rolling resistance seems like it would be insignificant.

mustangGT90210

Smaller tires will get you better mpgs also. But don't go too small or you'll run too high of RPM to reap the benefits

Square

Yes, lighter wheels and tires and even the type of tire would help. Don't get the nobby off road tires if you want efficency. Look for lighter weight wheels but make sure you check to see if they can handle the weight. Making sure you disconnect the front wheel hubs will help. A different grill isn't going to help. Basically, at that point you're just trying to polish a turd. A polished turd is still a turd. These trucks are about as aerodynamic as a brick. Lessening the air turbulance underneath the body would help but you have too much going against you there. The biggest thing you could do is change your driving habits.

Just my two cents.

aliens8mycow

polish a turd...

and you just end up getting poop stains on your new microfiber cloth!

Just call me Sean

iTrader: (1)

My turd is pretty shiny.

ymeski56

Good post.

In bicycle racing it has been proven that the most beneficial weight reductions are to those items that rotate. Tires, rims, hubs & crank. My race tires for my bike weigh 28 grams. My training tires weigh 40+ grams & feel like I'm dragging a trailer comparatively, as far as energy expenditure. While both run w/ 90-100 psi.

x2 on driving habits.(pretend you have an egg between your foot & the pedal)

Obviously, lifting a daily driver is shooting yourself in the foot as far as aerodynamics. Polish a turd..........Bahahaha!!!

Another line of of attack is go synthetic oil, milage increase is miniscule. However it's synths other attributes that make it a better choice overall.

Reducing combustion chamber deposits w/ a Seafoam treatment.

Lucas injector cleaner every 5th tank or so to ensure efficient injector atomization of fuel.

Then my favorite, Ignition system upgrade & base timing increase.
http://fullsizebronco.com/forum/show...mpOccasionally

Run error code scans. My TPS pooched on me & I lost 6 mpg in both tanks before I figured it out. That was 216 miles less driving from those two tanks.

These are tried & true "cheap dates" that will squeeze the most out of that .........brick!

Pine Barron

I guess the 4x4 is my real problem. I really like my truck, its got a good body, it has a nice good interior, nice body, and I've put a fair amount of work into it. Its kind of like the truck I always aspired to have as a kid. I like 4x4 since theres a lot of sand roads for exploring here in South Jersey. I'm going to be taking night classes in the spring. Was just hoping to cut down to one car and improve its mileage.

I did check out the Ecomodder site, which is where I kind of got my idea from. Always enjoy reading about creative ways to improve efficiency! Also theres a company that makes fiberglass body panels for short bed F150s (lightenings) to reduce weight. I guess to best accomplish my goal here, I'd want a 1992-1996 f150 4x2 shortbed.

I just got a deal on some slightly used BFG 31s a month ago, before I decided that I wanted to try to cut back to one vehicle, which can't be helping. My rear axle code is 19, so assuming it is original it is the open diff non-limited slip with 3.55 gearing. That and the stock six with a the m5r2 trans.

The grill bit was a thought from the ecomodder site. I'd been reading about wind resistance and was wondering if you could improve it enough on these trucks to actually make a difference, without going so far as building a boat tail on the back. I guess some of that ecomodder stuff is a bunch of miniscule things that should add up to a fraction of a mpg. Kind of like those ultra light backpackers who cut their toothbrush handles in half and then drill holes in whats left.

As I said above I replaced my 31s with another set of 31s about a month ago. I'm not too attached to them, since I got a really good deal on them, and I'm considering trading them on CL for a set of smaller tires on some lighter rims. Mine are on the stock steel rims which are probably heavier than american racing ones. After looking on some tire websites, it appears that my BFG All-Terrain T/As (31x10.5r15) weigh in at 42lb a piece, where the lighter smaller tires that other brands make are between 30 and 34lb a piece. If you consider the saying (which I just read and am going to butcher) that an ounce off the wheel weight is equivalent to 1 lb off the body weight, thats a huge difference (at a decrease of12 lb per tire it would be like taking 480 lb off the vehicle weight). This is probably an oversimplification, as this saying was developed about bicycles, but its probably not THAT far off.

I drive pretty modestly...always shifting slow and coasting to a stop in N. Right now I can get about 12.6 around town and just make 14mpg on the highway (Ive also figured out that my speedo is still set for stock tire size, so I factor that into my equation when calculating mpgs). Pulling a 3500lb trailer I get about 10.5 and pulling one thats about 1800lb I can get about 12.5. Working against me are a cap with a small roofrack, 4 wheel drive, and the 31s. Also after about 5 miles my inline fuel pump starts to whine proportionally to how hard I'm pushing down the pedal (when using either tank). When I checked my fuel pressure in the driveway it was still within normal range.

I've done the seafoam, although perhaps it needs to be redone...you just pointed out that some of the junk from last timeended up on my #6 spark plug! Before seafoam I could only get about 13.3 on the highway.

Ive read your other posts on the subject. Before yesterday I had already:
-fixed all exhaust problems
-new EGR
-new tps
-cleaned tps
-new o2 sensor
-new wheel bearings
-new pads and rotors
-change all the fluids with more expensive brands (tranny, transfer case, rear diff, oil)
-replaced plugs, 8mm wires, cap, and
-new water pump (belt driven)
-new thermostat (i believe it was the 192 degree one)
-new temp sensor
-cleaned up all electrical connections
-new pcv valve
-all new vacuum lines
-seafoam
-my friend advanced the timing a little (not sure how much)


This got me from about 10.5 around town and 12.5 on the hwy up to about 12.6 and 14 and fixed all my code problems.

Yesterday I:
-put in a new K&N air filter
-new crankcase breather (not sure if it will do anything, but the old one was REALLY nasty dirty)
-cleaned the sparkplugs up and regapped them from .45 to .55
-MSD coil
-bought a timing light

Today I'm hopefully going to learn to use the timing light and bump up the timing some more. I've got 60 mile hwy drive today and then again on sunday so we'll see how the mpgs are affected. After that I'm going to lose the cap and see how that affects things. And then after that I'll probably try swapping for different tires and rims.

ymeski56

Sound's like a pretty healthy brick you got there. Sounds like your starting to make peace w/ it's inherent limitations. I'd run error code scans for "grins" anyway.

Everybody want's to go to heaven, but nobody want's to die. Nothing does everything well. Not in our price range anyway! Starting to look like stock size tires will get you closer to the heaven you now have in mind.

For what your doing 14BTDC sounds good for a base time. I'd carry the timing light with you on the first couple of heavy tows, just in case an adjustment becomes necessary on the fly. You know all about the "SPOUT" plug right? & engine should be at operating temp for base time adjustment too?

Oh! Your the Seafoam/ Gumout plug massacre guy!
Engine should be at norm. op. temp. before treatment. Don't add to oil if fresh. Damn, I can be redundant.

On the pump whine, I'm tempted to say the tank pumps not keeping up, but you say it's both pumps. The other player's are the selector valve & fuel pressure regulator. Hmmm........... A bad regulator can run out a HP pump......But I would expect other symptoms. What's your fuel pressure?