1987 Ford F250 - 25mpg hwy or bust
 

Ok, so my night is boring enough I'll just start this now instead of waiting to have it running again (starter took a dive).

As I said in my intro thread, I a mechanic by trade, and I just stepped up to this from a 98 Ranger (28mpg hwy @ 70mph fully loaded). From a business standpoint, I'll be able to offer more to my customers, in the form of hauling more tools with me, more supplies, and with the larger truck, I can also offer hauling services such as pulling boats out of the lake or transporting vehicles or trailers. From an economy standpoint, my wallet is still screaming rape. The previous owner of this truck claims an 18mpg hwy rating, and I get the impression he drives like I do, so that's not too shabby a number for a truck that came off the scales at 6100lbs with me and my tools loaded up.

Ok, here's what I'm working with. Here's the truck, and a sampler of my typical daily load (everything that stays on the truck). This isn't everything, but it gets the point across.
http://i.imgur.com/IisuvVi.jpg
http://i.imgur.com/yqy6n5p.jpg
http://i.imgur.com/ojA2CLD.jpg

Ok, so that's the starting point. One big ass truck (compared to my Ranger), with a big ol' motor (6.9L of diesel snorting cast iron), and the aerodynamics of a chiseled brick. WOOHOO!! Now I've seen the thread talking about using a trailer vs a bigger vehicle. I do have a trailer, and while I could have setup everything upon that, I would then have had to take it with me on EVERY service call, rather than just the few that might require me to bring the customer equipment back to the shop. That would have dragged down my mileage in a worse fashion.

My goal with this is to do 25mpg or better on the highway, and 20 or better in town. Considering what this truck is currently rated at (figures taken from various personal inputs around the web), I don't see this being an unreasonable goal. So now lets break it down into categories or what I can do, what I want to, and what's out of the question.

First, what can I not do? What's out of the question?I cannot shed weight. As much as I love a good workout, I'm not loading and unloading my truck on a daily basis. One, I never know when I'll get a call to come right away. Two, I tend to cross territories and stop on the side of the road frequently (tow truck territory), and if the tools aren't with me, I make no money. This is my daily driver, it is also my bread and butter.

Second, what do I want to. One of the first thing's I'm planning to do is replace the factory bed with a flatbed. Yes, I understand this will mess with the aero of the truck, I have some ideas on that that I will get to in a minute. On this flatbed I will have cabinets on the sides, top and bottom, to hold my tools and supplies, leaving me with a wide open bed to haul cargo and equipment. This will also give me the benefit of being able to keep my equipment on the truck and still be able to haul large trailers, such as goosenecks or 5th wheels if I ever install a hitch for either. That's not directly related to my work, but I love a good roadtrip and don't mind hiring myself out once in a while. However I do put on a lot of highway miles going to and from customers (I provide service to my county and surrounding counties).


Ok, let's break it down from there.


Let's start with drivetrain.

My truck is powered by a 6.9L IDI diesel. I'm fairly limited on what I can do here. I can switch to an electric fan, I plan to upgrade to hydroboost braking and eliminating my vacuum pump, and I can run intake tubing from the air cleaner housing to somewhere on the front of the vehicle for a cooler, denser air charge. That is about the limits of my engine mods, short of swapping in a 7.3 w/ turbo (factory or Banks). Yes, I could also add a switch to turn my alternator on and off, but I rather like having a stereo in my truck (I'm relatively modest in my systems, but they're still there), and I feel that eliminating the vacuum pump will reduce loss more than the alternator would. I'm also a big fan of lighting, and being lit at all times. Between that and the stereo, it wouldn't take long to drain both batteries.

Transmission is a manual, so the drag and parasitic loss aren't present here (compared to an auto).

Rearend (truck is 2wd) gearing is 3.55 in a Ford/Sterling 10.25" axle, so it's already relatively economic. I'd love to go closer to 3.00, but the 3.55 is the lowest available gearing for this axle. I'm led to believe that the factory did offer one ratio that was closer to 3.00, but a lucky junkyard score will be my only hope. My only options for a gearing change to lower my cruising rpms are a GearVendors (expensive), an axle swap (still relatively expensive), or taller tires (lucky me, I need new ones by winter anyway). So we'll move to the tire selection.

Current tire size is 235/85-16, load range E. Being a big, heavy diesel that will regularly see loads (scrapping runs, towing, etc), I will not be going to a skinnier tire. If anything I'll actually be going a little wider. Yes, this would typically add to aero drag, but I'll discuss that later. I've been talking to Christ about this one. With the kind of miles I might start racking up, I'd like to move to a tire selection that will last a long time, be durable, and will have a load rating equal or greater to stock. So we've been discussing moving to semi tires. My current tire size is 31.73" tall, the tires I'm looking at (245/70-19.5) are 33" tall. I ran this through a gear calc, and assuming I cruise the highway at 65, my stock tires will keep me about 1890rpm. The 19.5's would put me about 1800-1810. This is 80-90rpm lower, or 4.25-4.75% lower. Not a dramatic decrease, but still fairly considerable (keep in mind max hp @3600rpm, max redline supposedly 4k rpm). The 19.5 tire combo will weigh about 100lbs or so per corner. My current spare has an improper tire size on it, 215/85-16, which weighed in today at 71lbs (tread is almost worn). Between the size difference and manufacturing tolerances, we'll say the 235/85-16 weighs 75lbs. So now we have a rough idea of 25lbs difference between the 19.5 and the stock 16.
This swap is not yet set in stone, it is just something I am floating as an idea.

Ok, what I'm doing, drivetrain, lets move on to electrical.
There's really not much to be said here. The diesel is fully mechanical, the only electric it actually consumes is the glowplugs and starter, and the fuel cutoff solenoid. Beyond that it's just lights, gauges, and my stereo. I do plan to upgrade to LED everywhere possible, and for the nature of my work there will be additional lighting, also LED. Obviously my work lighting will not be on during driving, so this wont be an issue.


Aero. Here is probably the biggest thing I can do for this truck. Buckle in folks, this will probably be the longest part of this post.
As I said earlier, I am planning on replacing the factory bed with a flatbed. Ideally my flatbed will be 7ft wide and 8ft long. Yes, this will stick out past the cab sides. Ok, let's start at the front of the truck and work our way back, shall we?

Bumper. With some of the things I carry with me (chains and jumper cables), I was initially planning on building a storage bumper, a box with an air dam below it. This bumper would have been angled inward from the top, and would have angled back on the sides. While browsing on here I came across a Blazer build by Oil Pan 4. He installed a sectioned Peterbilt bumper to use as an air dam. I like this idea more than my bumper, and plan to emulate it. I still require the storage up front for my chains and jumper cables, so the bumper will mount several inches forward of the grille and frame, so that I may implement the storage boxes in the space between. To help aid the aero, I plan to mount the bumper an inch or two above the stock bumper line, and fold the top over, make an angled lip from it. I feel this will help direct air up and over the hood (which also has an angled front). Said bumper will also be no closer to the ground than 8". I feel this will still aid in preventing the airflow under the truck, while allowing me suspension travel and clearance over speedbumps and potholes (some places I've been have some damned nasty potholes).

Moving back, wheels. As much as I'd love some good looking wheels, or even painted steelies with nice trim rings and center caps, moon discs will be better for aero. I can always paint those instead!

Little further back, visors. I do not know if they hurt or help aero in anyway, but I will have the vent visors on my windows, and I would love to have a Lund visor over my windshield. Does anyone have any experience with either of these helping or hindering airflow/aero? I'd love to hear from you about it.

Getting to the bed and it's obvious aero or lack thereof. As I mentioned earlier, the bed will be sticking out past the sides of the cab. To combat this, I had planned on "wings" attached to the cab behind the door and spreading out to the corners of the bed. since the toolboxes obviously wont be as tall as the cab, these "wings" would taper to a point from the top of the toolbox to the top of the cab. If anyone has anything to say about this, please chime in. I don't have it done yet, so I cannot tape streamers to the truck and see how well this would work or not work, so I'd love to hear what you think I might see with this.

Rear wheels. Along with wings on the cab to help blend to the bed, I'll also have skirts to cover the wheels.

Rear aero. I've been thinking about it, and for highway trips where the bed won't be stacked full of things, or at least wont be overly stacked with things, I was thinking it would be easy to setup a quick to setup/collapse kamback. Collapsible poles to hook to the headache rack and pin to the top of the toolboxes, and a rolled up cover to snap down over the frame and sides. When not in use, the poles slide into themselves and drop down on top of the toolboxes, and the cover would rollup and be tied to the top of the rack. Out of the way for daily work, and able to be setup/tore down in mere couple minutes.

Lastly, belly pan. Even with a fairly deep air dam of a bumper, I still plan to belly pan as much of the truck as possible. If nothing else, it will at least make cleanup of road grime and winter salt very quick and easy.

Let's see. Drivetrain, electrical, aero. I reckon that's about it. The only other thing is a possible waste motor oil conversion, but that's a conversation I'll be having over on Ford-Trucks with fellow IDI owners. Any changes I make in that regard, I'll definitely document here though.

So that should just about wrap it up folks. That's my truck, that's what I have planned, and what I'd like to do. I'd love to hear from everybody about my ideas and how well they'll do or how much they suck. I have a realistic goal of 25mpg highway, with a dream of maybe touching 30. Let's see how close I can get!

I got nothin'. Build it.

I'd stay away from the windshield visor. I have nothing but instinct that tells me they cannot be good for drag reduction. I'd mod the factory interior visors if you need more coverage to cut down glare.

Same opinion on side window visors, which also increase frontal area by the way (double aero whammy).

^^
I'm with Metro. I know the shade is good, but I can't help but think it'll act as a big ol' air bucket. And with the 250 you've got enough to make up for without bolting on even more. Could you achieve similar results with a band of blackout tint along the top of the windshield? I know you can usually tint all the way down to the A1 line without incurring the wrath of the local constabulary.

A tint band is a good idea.

I planned to add a tint band anyway, the visor was about 50/50 looks and light blocking. I do know that most of the Lund visors have a gap between the visor and body to allow air to pass.
The window visors on the other hand, those are more about the function. I've got wing windows on this truck, but sometimes I just prefer to roll down the main window. When it's raining this obviously allows water in. With the wing windows, I wouldn't be getting the full length visors, I'd be getting the shorter ones, like these.
http://i774.photobucket.com/albums/y...indowVisor.jpg

Weighed the spare tire I have, and am adding that info to my original post.

In response to cRiPpLe_rOoStEr in my intro thread, an alu flatbed would be ideal, but I'd have to have it made from scratch. Right now it'll be easier for me to find an existing steel/wood flatbed, or to make one from scratch using wood.

Weight of steel/wood bed currently unknown
Weight of wood bed (not including toolboxes, size, or rear planking (frame cover) roughly 360lbs.
Weight of factory bed currently unknown


I had not yet considered fibreglass bodywork for the front end. I do know it would be lighter, but I'd be worried about durability (I'm just nasty to my work trucks).



In response to MetroMPG, fuel efficiency instrumentation would be lovely, unfortunately there is almost nothing electrical about this truck, and therefore I would be unable to use it. I will be limited to calculating my mileage via miles driven VS gallons used (gas station math).



In response to Deejaaa, I probably should have mentioned this earlier, but I'm attempting to do this relatively cheap. GearVendors units are pretty pricey, even used. A lot of the things I'm adding or modding I'm doing so because they need to happen anyways (like tires) or because I'll already be doing them to increase function (storage bumper, flatbed, etc). The GV unit falls into neither of these categories.

Dean - The gap in the Lund visor is actually worse for aero /because/ it allows air to pass, but not in enough volume to make up for the drag the part itself induces. It'd be better as a sealed unit, but the tiny screws in sheet metal wouldn't hold up to the wind pounding, which is why those vents are there.

If you do decide to use a visor, go with something like a short-tuck style, seen on many large trucks. The front visor is just a no-win situation.

Also - Fine. I'll sub this thread too.

Pictures of truck added to OP

Those side window visors are a bugbear to me. My new Civic has them - previous owner added them - and the wife loves them. LOVES THEM. She doesn't want them taken off. Being considerably more interested in domestic tranquility than that last .1mpg, I'm willing to overlook them. But still - I can't forget about that last .1mpg.

That and she has the car today. That's another 50 miles of serious hypermiling to try to get the average back up.

Other easy areas to look at:

-Mirrors
-Fluids
-Driving techniques

I think the added weight from the tires will cancel out any gains from the lower rpm's unless you are doing drastically more highway than rural/city driving.

Smaller mirrors or adding aero forms to the fronts of the existing ones can be a good idea.

I've experienced anecdotal gains of 2mpg switching to synthetic fluids all the way around. Then biggest gains are supposed to be in the differential.

With a truck driving habits are going to go a long way. Any time you have the chance to sacrifice some speed, let's say by going 55 instead of 65 you are going to notice huge results. The worse your aero is (and yours is terrible at best) the more higher speeds kill fuel economy. Here is an example of how Diesel_Dave drives to get 328% above EPA with optimal driving (along with some mods).
http://ecomodder.com/forum/member-di...-mile-tank.png
http://ecomodder.com/forum/showthrea...a-26259-5.html

I'd like to swap out my current mirrors for the newer style ones, but that will require me to replace the entire door (I'm ok with this. will give me a chance to find some cleaner ones). The downside to this is that with the flatbed I plan to build, or service body I install (I might have found one at a very reasonable price) and the trailers I'm likely to start towing, I'll need more mirror than those. I was looking at some of the semi style mirrors. I notice newer ones have a curved back to them now, rather than being flat, giving them a little aero over the old ones. How much, I'm uncertain, but I'll definitely document any changes from baseline when I get them.

As for driving habits, I've already slowed waaaaay down from how I used to drive the Ranger (god that little guy was fun). The majority of my driving around here would be described as rural or highway. I live in a rather small town (google Elkhorn, Wi), and most shopping and customers are a drive away. I spend most of my driving time doing either 25-30 or 45-60, depending on in town or out in the county. On the highway I'm not sure I'm really comfortable with this truck much over 65 anyway, so 65 is likely to be my main highway speed.

First mod should be to take one of those chains and loop through the handle on each tool box and lock it at each end.
Ever try working with out tools? Trust me it sucks when some degenerate runs off with your equipment just so they can get high.
My power washer, one of my top money makers and a hand truck got ripped off not too long ago.

My truck vs. trailer thread is to offer a suggestion to replace a pickup with a trailer for people who only need the use of a pickup occasionally.

Second mod should be electric fan conversion or an air dam, when I did the electric conversion I picked up about 2mpg, the air dam netted me 1 to 1.5mph.
Both are fairly easy to do, quick and give good return.

A turbocharger should come after that. Start looking for parts now. When I installed my holset HE351VE turbocharger off a 2007.5-2010 cummins I gained 2 to 2.5 MPG and gained plenty of power. Just don't put a factory sized turbo on it, we consider them too small to go on the chevy 6.2L diesel. Go big with the turbo and don't use the factory piping where you can help it, get what ever banks parts you can. I use a banks exhaust manifold and glad I did.

Don't worry about the vacuum pump, its likely only about a 0.1 MPG improvement as calculated on paper, I did a vacuum pump delete and saw no difference.

Don't worry too much about weight reduction, your truck has close to the same weight and lack of aerodynamics as my suburban, each 100lb that you shave off will only net about 0.1mpg on paper and my towing logs indicate 1mpg loss with the addition of as little as 500lb. You would have to shed hundreds of pounds to get any noticeable improvement.

+10 on the e-fan upgrade - and it is an upgrade. The fan hardly actually needs to run to cool the engine at all when you're at speed. Don't forget to wire it in using a thermo-switch. If you have a rad that has the auto trans ports on it, plug one side, fill the tube with coolant/water mix and put the thermoswitch in the other side. Saves on having to mod things.

Here is some light reading that will give you some ideas and maybe answer a few question.
http://ecomodder.com/forum/showthrea...uck-18187.html
http://ecomodder.com/forum/showthrea...ger-18197.html
http://ecomodder.com/forum/showthrea...dam-26600.html

Search the forum under the name "Jacob Aziza", He has an older F150 and gets the kind of mileage you are looking for and he is hauling heavy scrap virtually all the time. There are even some videos of his driving technique.

regards
Mech

Some newer big rigs, with all the enhanced aerodynamic jobs they're featuring, have smaller auxiliary mirrors with convex lenses bolted into the front fenders.

I don't have much problem with theft here. The truck comes home with my every night, stays parked right outside my bedroom window actually. Myself and one of my neighbors are both up until late hours of the night, so it's easy to keep watch. Add that to the very low crime rate (we have a rather sizable LEO presence, being the county seat....and the fact that the sheriffs are based right down the road) and I'm relatively comfortable leaving everything in the truck. It helps that I help my neighbors and we all watch out for each other lol.

The comment about the truck vs trailer was by no means a slight against you, I just know it's a fairly active topic and would have come up. When I still had the Ranger I actually was considering attempting to setup the trailer to work from.


For the electric fan, it's something I already want to do. My only concern with it is that on FTE I've seen people talk about the fan not keeping up with the temps during towing or hauling large loads. As large as my radiator is, I could run at least 2 fans, I'm sure this would solve the problem those people have had, noone ever mentioned having multiple fans.

Turbo would be nice, both for power and (with proper tuning) MPG, but the Banks kit is the only bolt on option for my truck (and I think it's actually geared more toward the 7.3, I could be wrong), and for the cost of the Banks kit or even a homebrew, I'd rather put the money in other areas first.

The vacuum pump delete isn't entirely about mileage. I should confess that the other reason I want it gone is it's one less belt under the hood. I have 2 belts that run together to drive the water pump and power steering, then another belt that drives just the alternator. A 4th belt runs from the alternator for the sole purpose of the vacuum pump. Switching to hydroboost nets me something of a brake upgrade, as well as one less belt running off the engine (or it's accessories).

Considering the weight of the truck and what I do, weight loss is the least fruitful option anyway. The way I look at it, the extra weight can actually help on the highway. When doing the pulse & glide, the extra weight means more momentum, more time before pulsing. The flip side is that it will take more grunt/time to pulse back up, but it could work out to be slightly on the positive side.


I did actually read all through your work truck build. The air dam will come in the form of the bumper I mentioned in my OP.


There are some mirrors I've used recently that I would like to adapt to my truck if possible. My neighbor had a box van that he used with his hot dog cart, and it had a double mirror on each side (tall setup with a regular mirror and a convex mirror), in a fairly aero housing. I'd like to see if I could adapt this to work on my truck.


I will definitely look into this. I've got a starter on the way, I should hopefully have my truck back on the road sometime next week. Also picked up some good used tires, so I can at least not worry about those for the time being. I still want to buy a new set, so I'd still like to see some discussion regarding that.

Dual-fan setups such as the one from the early Oldsmobile Silhouette/Pontiac Trans Sport/Chevrolet Lumina APV with dual-zone air-conditioner have some good results in Diesel conversions too.


This setup is very usual in European vans.

One easy way to delete the belt driven vacuum pump and still keep your vac system is install an electric vacuum pump with a small vacuum tank up under the truck along the frame rail some where.

There is a lot of room under these trucks and even more so if you can let stuff hang down a little, but I think you can only do that as long as you don't have to worry about deep snow or off road mud pits tearing stuff out from under your truck.

The hydroboost system installs in place of the vac booster, provides about half again the braking power of the stock vacuum booster, and only requires one new hose from the PS pump that's already running all the time, even when you're not steering.

I have hydro boost, and it looks like a pretty big commitment of time and money to go from a vacuum brake booster to a hydro boost especially for no MPG benefit when you are trying to gain MPGs.

It's not. I've done the conversion about 30 times now, it takes less than a couple hours. I was in the process of doing it on my F250 when I got my Chevy 2500HD and scrapped the F250 in lieu of doing $1000 worth of body work on it.

...but I did pull the 7.3 from it.

Truck is back up and running. And now the fun starts! :D

I've got a couple more maintenance things to do before I can start actual modding, things like tires, but I'm looking forward to seeing how this goes. Just started a new job, so I should be able to keep it full of fuel regularly so I can get consistent mileage readings. I'm gonna fill it up when I get my next paycheck, and start keeping track from there. I plan to buy a notebook to keep in the truck specifically for recording mileage.

Even if you can't do a full fill up you can log the number of miles driven and gallons added in your book then total it all up next time you fill up.

Those side visors are popular on TDI's, but I see a lot of shocked comments about how much of a ht the fuel economy takes. It's a lot more than 0.1 mpg on the highway.

Finally got my first full tank the other night. Doing my regular drive to work with a few errands here and there, will fill up this coming weekend when I get paid, see where I'm at for a baseline.

On a baseline, I seem to be getting around 15mpg. Most of my driving is small town/short hwy. Now for the improvements to start XD

Oughta put up pics of the 'zorst.. keep 'em entertained. ;)

As long as it's a load range E tire, you will sacrifice no load carrying capability by going to a 215 85R16 tire, for example. That may give you a slight increase in fuel economy.

What about doing the PS pump on an AC clutch? Turn it off when you don't need it?

Being a 3/4 ton, it probably has a TTB front suspension right? If it has the beam axle, that would make it easy to do a belly pan. Even if not, you should be able to make one that bolts to the frame for most of the truck.

OK, I'm a newbie here, BUT: got a 2000 f250 6 speed & 3.73 rear end that I claim @ 20+ mpg city for 135000 miles. Back before fuel reformulation i got 25 mpg stock summer. Not a lot of differences between the 250 and 350. In this case, axle spacers and door stickers. Yes I have the turbo and intercooler, but don't run a lot of boost.

stuff I did: cab top campershell with BOOT not windows. played with raising and lowering. raising it cost me 5% for every inch up, lowering it did approx the same for increases. I suggest using the 250 rear axle spacers which lowers the rear about 2" at a mild load capacity loss which can be avoided with helper springs\airbags. NEVER go above 2000 rpm, try to stay at 1750 which is theoretical best efficiency if you can trust Ford owner's documents. I run really lean because of a fuel pump issue (about -28 on LTFT)

Heavy it responds best with hypermile techniques because all that mass doesn't want to stop. I just whine a lot starting off and while going up hills.

YMWV

I plan to go to hydroboost, disconnecting the steering would be a bad idea. As for the tires, the 215 will be shorter than the 235, which would correct my speedometer, but throw my odometer. Oddly enough, one is spot on, one is fast lol. The narrower profile would help the aero, but it might not be noticed with the belly pan and the massive airdam I plan to install.



2000 will be the Powerstroke, which I understand was more efficient to begin with. I totally hear you on the fuel though. I've noticed how the gas formulations have changed over the years and the effects they've had.

A camper shell is out of the question for me, the stock bed is coming off in favor of a flatbed with cabinets. I do have a collapsible kammback planned for highway trips though.

Any lowering I do on the rear of my truck is gonna have to happen by way of longer shackles and/or hanger flips. My truck doesn't have the spacers and tall perches like some others do, the leaves on mine sit directly on the axle pad. I do want the truck lower, and I'll go as low as I can without flipping the axle. I'll have to get the dream beams for the front and some shorter coils as well. I don't see going much lower than 3 inches though. It's a 3/4 ton not a half ton lol.

I try to keep the revs fairly low, but the new exhaust is just lovely to listen to...I can't help the urge to play around some lol.

You also have a completely different engine that's direct injection and turbocharged... it's more efficient right out of the box.