40 + mpg out of a mid size truck?

[Jim Allen]

Originally Posted by JacobAziza

:P
This thread has been very entertaining to catch up on!
Very.

Ok.
I genuinely have been getting 25mpg.
Thats average, over many tanks, many months.
I use the truck for moves, hauling, and transporting tools to jobs. I'll fit a 1bdrm apt in the back, boxes, furniture, everything the customer owns, all in one trip. I haul 3 tons of soil, rocks, or broken concrete. I recently moved a 2000lb safe. This is all a mix of freeway and city streets.

I don't have any instant feedback, so any number I have is an average over an entire tank.
My best mileage to date is 28.5mpg.
The 28.5mpg run way empty one way, and then about 1000lbs on the return trip.

I didn't say I haven't done any mods, just none that involved fabrication or needed a mechanic or special tools or anything expensive.
I have done quite a bit of modding (coroplast aero mods and accessory downgrades) but all things that would be in easy reach of the thread topic original poster.
I wrote up all my mods here:
Vehicle efficiency upgrades: 28.5mpg (so far) in 2.5ton commercial truck
Easy, cheap stuff.

Driving style is a big part of it too. Frank Lee is right (assuming he can run 50mph). I drive slower than normal, but that is because my truck has no overdrive- its max efficiency is around 25-35mph.
Someday when I can afford a 4spd tranny, I'll start driving 55 (the limit for commercial trucks, which- technically- mine is)


The auto companies have always known how to get better mileage. The problem isn't them. Its the American consumer. They all make efficient vehicles - to sell in Europe, Asia, and Latin America. GM makes a van - not a mini van, but a commercial van - that gets 45mpg. Sold in China. Hybrids sell here because you can get kind of decent mileage while still having A/C and thick cushy seats and 8-second 0-60 acceleration and 20 million electric gizmos and lots of truck space and room for 6 people even though 80% of our car trips have only 1 or 2 occupants.


Incidentally, I just turned my tonneau into a makeshift aerocap by putting the rails on triangle pieces of plywood.
Its too soon to say if it makes any difference at all.
If it does, I'll mention it on my original thread about the truck: http://ecomodder.com/forum/showthrea...-2-a-8613.html

And I totally agree with alohaspirit: if you are only using a vehicle occasionally, it usually makes more sense to rent one than own your own.

I got to this point on this thread and finally have to chime in. I have the same truck as you, or nearly so ('86 F250HD), and have owned it since it was almost new. I know the truck very well. It has some advantages yours may not, such as a Banks turbo kit (installed in '87) and a very precisely calibrated pump and injectors. It has some liabilities your doesn't, such as 4.10 gears, 4WD and, at times in it's life, wide tires. I have tracked the mpg since I've owned it and pretty much know what it will deliver in every circumstance. The truck has NEVER broken 20 MPG! The best it ever did was about 19 and that was with very concentrated effort at 55mph. My truck weighs 6250 pounds without driver and half a load of fuel and has the frontal area of a house. Speed is the killer with this truck and the solo rules of thumb are up to about 16-16.5 mpg at a steady 55, 14-15 at 65 and not much more than 13.5-14 at 70 (it's revving at 3000 rpm at that point... no OD).

Here's the part to pay attention to: One thing I noted right off was that the odo/speedo was inaccurate from day one. In checking around, this seems universal in that era of truck. The odo/speedo read 10 percent more than actual with the factory sized 235/85R16 tires. When I read 250 miles, I had really only travelled 225. I was seeing 17-18 mpg pretty regularly in my ignorance and feeling pretty happy about it. When I calculated the error and factored it in, that 17-18 was only 15-16. Tried to find a speedo drive gear to correct the error, couldn't, and finally ended up with taller tires (wider as well as taller, but a 33 inch tall mounted hight just about zeros the error) and it's pretty close to accurate now. The wider tires (285 vs 235) cost about .5 mpg at highway cruising speed, however.

Beyond outright bovine scatology, bottom line, our MPG claims are only as accurate as our instrumentation.

Depending on your truck's gear ratio and tires, I do not completely discount your mileage claims as fantasy, but both my eyebrows are up. If I deduct about 10 percent for odo error, and consider that you are driving at less than 50 mph, I can just about believe the solo mileage. I've never driven mine that slow for any great length of time.

Loaded??? I used to regularly tow at about 19K GCVWR with this truck and on it's best days, it could average a bit over 10 mpg... and I was happy to get it. A neighbor had the same truck with a 460 gas V8 and in the same circumstances, his best was about 7.5 mpg. I hauled about 2000 pounds (four engines) on a long trip once and the truck got about 14mpg at 60 mph.

Back to the OP, I think it's a waste to spend a bunch on money to hypermile a truck.... for the reasons so aptly expressed above. Most people don't need a truck on a daily basis. If you need on often, it's often cheaper to keep it as a second vehicle and use it when needed.

[JacobAziza]

I don't have a turbo, but the 4wd hurts mpg a lot, and your truck is about 1k#s heavier than mine. You also have an automatic.

Before I started modding and hypermileing I was getting about 15-17mpg too (assuming odo is accurate) - in fact I never got as high as 19.
I have also found that towing hurts mpg much more than having a load in the bed.

Have you checked the link to my instructable or my post here that details what I've changed? I've removed all belt driven accessories (including alternator), installed coroplast underbelly tray/grill block/wheel well covers, among other things, and I EOC at every possible opportunity (which I assume, having an automatic, you never do)
With each change I saw a slight improvement and gradually gained about 10mpg. If the odo is inaccurate and I was getting only, say, 12-15 that would still put me around 22+ now.

Today I'll check the odo vs. g-maps. I just ordered a GPS last night too, (which even keeps track of mpg if you tell it gallons of fuel at each fill) so we'll have a more accurate calculation (to not believe )

[Jim Allen]

I admire your calm replies in the face of the challenges. I hope you regarded mine as sufficiently polite.

You have carried your mpg quest way beyond what I would. Mine is largely configured as I need it. I need the wide tires for floatation on soft ground and the 4wd for the same reasons. The low gears were not a liability towing at relatively low speeds. The old truck is "semi-retired" ( I couldn't bear to sell ti when I got the new truck) and only gets 2-3K a year on it now. It does better in town and for short hops than my much newer gas truck does. It's great for hauling loaded grain wagons to the elevator (30-40 tons worth) and for hauling heavy loads (3,400 pounds of gravel in the bed last Wednesday).

[JacobAziza]

lol
yeah, seriously, I'm finding this more funny than offensive.
like someone pointed out before, I don't really care about proving anything to a bunch of strangers on the inter-webs. I'm just here to share and collect information and help reduce our dependence on foreign oil.

Besides, you raise a totally valid point about the accuracy of odos
I know my motorcycle speedo runs about 7% high from the factory.
I kept track of odo readings throughout my 3 jobs today, but have yet to cross reference them against google maps.

I only spent a few hundred on all of my mods (majority of that was electrical upgrades - LED lighting all around, 120v battery charger and 2 deepcycles - to compensate for removing the alternator)
Because I put so many miles on the truck (it provides my primary source of income) and because the 100% biodiesel I run it on is expensive, I should save roughly $1000 a year on fuel bills.

-EDIT- I took a couple wrong turns so its hard to have a 100% accurate comparison, but it looks like the odo is just about spot on with google. GPS is supposed to show up in 2 days...

[alohaspirit]

why dont you run veggie?

[JacobAziza]

its a lot of work to find places to pick it up, pump it out, transport it home, filter it, store it, plus you need to switch tanks every single time you start and stop for more than a couple hours in winter time.
I don't have the patience for the work or the room for storage.
With the biodiesel, no truck mods to accommodate it, I just pull into the filling station, pump, and drive away, just like normal.

[alohaspirit]

Originally Posted by JacobAziza

its a lot of work to find places to pick it up, pump it out, transport it home, filter it, store it, plus you need to switch tanks every single time you start and stop for more than a couple hours in winter time.
I don't have the patience for the work or the room for storage.
With the biodiesel, no truck mods to accommodate it, I just pull into the filling station, pump, and drive away, just like normal.

when compared to aero

driving on veggie has more impact on the
environment and ultimately saves you more money


but bio + aero is admittingly easier to do

[aerohead]

Last time out in the T-100 I hit 39-mpg on one short leg of the trip,between Cloudcroft,NM,and Artesia,NM.
It was only 88 miles of driving,and at the old 55-mph speed.
I have seen this MPG one time before,but at a steady 45-mph for 200 miles.
I think 40 is doable,but for the T-100,I think it will require the trailer.

[JacobAziza]

Originally Posted by alohaspirit

driving on veggie has more impact on the
environment and ultimately saves you more money

the place I buy biodiesel sources 100% recycled veggie oil

[Christ]

yeah, driving on veggie oil sure does have more of an impact on the environment... burning it in engines releases glyceride compounds into the air, which are poisonous to the people breathing them in. sure, it's carbon neutral, but that doesn't change the fact that it has negative effects on the environment.

In case anyone thinks that glycerine gets burned in the engine, look up the combustion temperature for Glycerine... it's about 1,800*F, or ~1,000*C, and needs to be sustained there. Guess what temps your engine doesn't reach and sustain?

When brewing biodiesel Glycerine is a by-product, which can have many uses, including soap and fertilizer. After refining, it can also be used in medical fields.