5 MPG to 20 MPG what will it take?
 

to those of you who haven't met groovy, well here he is. originally misposted in the "introductions" forum where he got very little attention
i am now in the proper arena hoping to get positive and constructive hints, tips, ideas, advice and inspiration on how to turn this high roof brick into an as efficient as possible roadworthy hauler. much like aerohead and Big Dave
i hope to raise awareness that with careful planing and driving even large vehicles can be efficient.

Thank you to all of you who tirelessly commented on groovys paint, lets talk aero this time!

here are the specs:

1991 Ford E-350 (1ton) dually (4X2), 16" LT tires, 3-speed overdrive Auto
i believe EOD, the cargo box is 8' wide 12' long and 7 1/2' high.
it is powered by a grossly neglected Ford (International Harvester) NA 7.3L (445 cu), IDI (pre powerstroke) diesel engine. i dont know the compression values neither do I have any leakdown data. i have acquired an area specific
ATS aftermarket turbocharger (not the castrated factory one). should the engine prove healthy enough it will be fitted. for now what you see is what you get. i drove it once and it was like watching fuel drain out of a bathtub.
more concerned with getting it home little attention was paid to MPG. previous owner claimed 10, but it was more like 5. the truck was empty!

FYI: i intend to fab an extension to the cargo box which will potrude over
the cab area; think cabover camper. 2 reasons:
1) to provide a small nook for a place to sleep when the truck is loaded to the brim.
2) equally important to provide a spot for an inlet for a through duct which will allow a portion of the air which has spilled over the cab and would normally encounter a flat 3' tall x 8' wide wall to take a shortcut and go through the vehicle instead of around it. on the inside the air vented from the high pressure zone in front of that wall will be channeled into a collapsible duct which in turn is connected to a hole in the rear cargo door where it will be drawn (augmented) into the low pressure zone behind the moving vehicle.

here is an area set aside specifically for discussing ducts:
http://ecomodder.com/forum/showthrea...tml#post204004

the realisation for a grave need for aero improvements came when decending
the north grade of the "grapevine" -- a brutally fast downhill section on I-5 in southern california. a nighmare for truckers a fantastic place to cook your brakes. a gravity racers wet dream. the truck "broke" itself, i tapped the brakes twice, only to aviod traffic!!

I think you are starting with the wrong vehicle. Seriously.

A three speed tranny is a serious handycap. Only getting 5 suggests something wrong in the engine.

5 to 20? It will take more than a duct, I guarantee it.

yes there is something wrong with the engine
 

- it shoulda been a cummins :D

3 regular and one overdrive. gear ratio is not too terrible actually
non functioning glowplug system
low compression
over over overdue injector maitenance
been run low on oil

merit
 

good to see you think there is merit in ducting afterall. aerohead don't think so. yes it will take quite a bit, at this point i am thinking of a combination of things but the execution and more importantly coordination of the sum of them will be critical for success! 20 might be pushing it :p

As a form of street vehicle drag reduction, no, I don't see any merit to it.

Recycle it.
It's obviously beyond economical reuse.
Even if you get it back in decent shape, it won't return decent MPG for only a 1 ton load.

You can try the obvious aero mods. Air dam, side skirts, maybe a partial Kammback
Also, you could put some sort of dome on the top of your cab, to make the box a little more streamlined.

I don't think that ducting will work, though. You need to make your box a little less box shaped.

But be sure to fix your mechanicals first.

http://ecomodder.com/forum/showthrea...tion-8872.html

There, I fixed it.

This is one of those projects that creeps into the back of your mind every now and then, as you haven't seen any posts on it, and you wonder what ever happened with it.

get one of these until you fabricate that sleeping nook. the airdam I mean, not a new truck. ;)
http://images.campingworld.com/is/im...8000/8696A.JPG

Enclose the bottom of the front end; most of the suspension is hanging out in the wind. preferably add a complete underbody that is smooth.

Even an NA diesel should get better than 5 mpg; fix that thing! The fuel system likely needs a *lot* of TLC to clean it up.

A turbo diesel is like a turbo gas engine; for a given *power* range, the turbocharged smaller engine is more economical for light duty use than the larger NA engine. If you already have the power you need, it really won't give you much fuel economy improvement to add a turbo. You would need to swap out the current engine for a smaller turbocharged one to see big gains from a turbocharged diesel.

How much fabrication are you willing to do to that cube?

Edit: Also, check your alignment. It probably isn't that good.

drove a truck almost exactly like this one for a Job I had in the early 90's and IIRC, it got 11-12 mpg.

Could be wrong, been a while.

First, as everyone has suggested, make sure it's in good working order.

second run a ad on Craigs list.

Third buy a Ford Transit.

JOKe.

Have you though t about lowering it?

I would try to get the truck lower. Also

Get a new engine. It'll be more bang for the buck than fixing that one with all the problems you listed.

I tend to agree here, I'm all for fixing but a NA diesel with low compression is not the most enjoyable thing to diagnose or repair...

That said HOW much below the allowable spec is it? if its close and you can't afford to fix just add some sort of top tube to the diesel like MMO, 2cycle, Diesel Service or whatever. Your compression will improve a bit. I do know that the Ford NA 7.3 was very reliable for the most part but that was about its only redeeming feature (my father owned a casino bus craftmobile with one). It was not as fuel efficient as other diesel offerings but could run down the road with a cracked block and broken crank if you had to.

Next thing I would offer is if you want the vehicle to be more aero and you could tolerate a loss of area weld and cut the front of the box at an angle (not sure which would be most effective) to the cab, not sure how much it would help if at all. The other possibility would be to extend the rear a bit and add a slope at the proper angle to the rear doors if you could tolerate a lower door height.
Or just lower the hole roof down if you can tolerate less clearance that would do the most with the leave work.

Cheers
Ryan

I agree 100%. You might even be able to find a powerstroke in a boneyard that might swap in really easy. And concerning the transmission, is the 3rd gear ratio 1:1 or overdrive? I suspect it is 1:1, meaning a transmission upgrade will be essential for getting decent mileage on the highway.

I must ask, what purpose will this vehicle serve? Unless you're prone to insane whims you must have bought it for a reason.

I would tend to disagree on the powerstroke, you enter into another maze of model years, overpriced maintenance items and varying potential breakdowns depending on which year and type.

Another 7.3 NA (or even 6.9 if power doesn't matter), operating in proper form is probably bang for buck the best replacement value if you end up going that route.

Putting in a powerstroke you might as well put in a cummins or change the transmission to a MT. Sounds like too much investment for the amount of use the vehicle will likely receive.

My take
Ryan

The reason I mentioned the PS was due to the possibility of an easy fitment. Depending on his skill, I would say a 3.9L Cummins would do fine, and get better mileage, or even one of the Mercedes 5 cylinder diesels used in the Dodge Sprinter. The Mercedes is a true winner, with a higher red line and common rail injection.

In defense of the PS, I have a friend with a 96 F-250 with crew cab, 4wd, auto, and long bed, as well as a lead foot, and he gets from 19-20 mpg. So it can be a good engine, although I admit it being a bit overkill in the displacement area.

When I was on a diesel forum, it was common knowledge that adding a turbo generally improved economy by helping to reduce unburnt fuel. Assuming the fuel screw isn't adjusted from the NA setting, economy can only go up.

And again, the question is what purpose will the van serve? That will help with the question of how much to spend on a refitment of drivetrain components. If it sees little use, I'd say fix the engine.

Seriously, something is horrendusly wrong with your truck to get 5mpg...

My godfathers 10mpg escalade truck....

I wonder if people behind him can see anything with all the smoke.

I also wonder if he miscalculated the mileage.

My friends full size school bus is getting better mileage, a semi with a full trailer should even get slightly better mileage!

Have you said what this vehicle is going to be used for?

Years back Caterpillar 500s got 5-6 MPG hauling a full load at 70MPH.
I hate to sound down, but fixing up a NA diesel is a waste of money.
For the box, why duct it? If you don't need the space the duct will use, just chop the top level with the cab.

OK, buy a bus. Mine gets 12mpg. Just a thought. Cummins, 5 speed, and some aero modding will make it much better.

A bus is actually more aero than a box truck.

And guys quit hating on NA diesel, that isn't really the problem.

A NA diesel CAN get better than a turbo varient but only if it is running in its ideal range, if its smoking a lot you obviously are not running in the ideal range.
Also the 7.3 is NOT an efficient turbo or non-turbo diesel, adding a turbo to one in my experience does not normally improve mileage. So throw the turbo always makes it more efficient out the window. That same statement was true of the 6.2, some 6.2's would do better fe wise after a turbo others were a whole lot worse. A turbo lets you burn more fuel more rapidly while using some power to force in air.

That said my 6.2 which was non-turbo got 10mpg running to the floor at 60mph pulling a 26' trailer and a 10' trailer at the same time over 10k in weight and that was with a 3 speed auto.

I know several who have a cummins that get in the 10mpg area but normally its a lot of weight or something real high. I have also encountered several ex box trucks with cummins motors that only get about 10-12mpg.

So in other words what he is DRIVING is the problem, he likely regardless of the motor is not going to exceed 12mpg without a MT transmission and extreme hypermiling with slow speeds.

A non-turbo diesel running a 22:1 compression ratio can potentially be more efficient than a 18:1 turbo'd motor if the motor is run in its efficient range.

Also my old 6.2 started a lot easier in winter than the ford and cummins versions I've encountered, likely because of its higher compression ratio.

I would love to own a properly designed naturally aspirated diesel suburban (or really any big iron naturally aspirated diesel car) of a more modern decent if such a thing existed. Pop in a 5sp manual and 30mpg craft mobile here we come. A 50mpg buick lesabre might be possible with old iron.

Cheers
Ryan

Just trade it in for an '04.5 to 06 Duramax, edge programmer, 4" cat back, bingo 20mpg...I get that almost every tank. 22.8 once but i pushed it into neutral alot for coasting!

As for NA diesel, they might work well in a certain rpm band, good for forklifts. ecomodding 101 is get up to speed then lug the engine, 4 seconds at 10mpg is better than 20 seconds at 10 mpg to get to the same speed. My trucks luggs along getting 30 mpg's after I get it up to speed.

My 4 cents

Well, if you're in California, you might just get some medals and whatnot for running biodiesel. Although if it is SoCal, you might have trouble finding a place that has any fry grease at all :)

A peterbilt 375 gets 4 MPG. Your box truck should not get 5 MPG. As the previous posters have said, it is likely your engine's fault.

Make sure it is running as well as you can possibly make it. Then, for the transmission, find a 5 speed, then put that on your 7.3. If you're feeling even more adventurous, go with a 9 speed non-synchromesh tranny like in semi trucks :) you'd have more gear ratios to chose from.


And, yes, aerodynamics play a big role if you do highway deliveries. City will be mostly the massive weight if the vehicle.

gas moving van = 8+ mpg
 

John,I worked a couple years with a local moving company and the largest unit,a Ford truck-based moving van with big gasoline V-8 got over 8-mpg.Only mod was a 'Nosecone' recycled from a local wrecking lot.
I agree with the others that somethings amiss with the diesel.
A local resident owns a 'Vixen' motorhome and has reported 30-mpg with the 5-cyl diesel 5-speed( maybe 6-spd).It's probably less frontal area than your rig,certainly a lower Cd.
80,000-lb 10-wheel semis have hit 10-mpg.
20-mpg might be doable but you'd have to do 'everything' and something like a modern Sprinter might end up costing less,if those had enough interior volume.

Today at work I downloaded the trip info from an ISX 550 HP, 1850 ft/lb torque in a Peterbilt 379, 18 speed. Pulls heavy haul Canadian super b-train weights (140,000 lbs) over the biggest elevation changes on this continent and cruises at 68 mph:::: 4.8 MPG (US).

Smoky old 7.3s (or 6.9s or 6.2s or 6.5s or whatever) are the result of worn out fuel system parts...pumps and injectors that need serious attention. Bluish stinky diesel smoke is fuel that never really caught on fire and did any work. The more there is, the more fuel you are basically pouring down the drain. This is completely different than black smoke exiting a heavily loaded diesel, which is caused by insufficient charge air...aka too rich. If you must, get a set of reman injectors and an injection pump. It will make a world of difference. But be sure to do a compression test first so it's not all for naught. A quick Google search has injectors priced at $28/ea and an injection pump at $415 = $639. Peanuts.

peeeeewwww!
 

you saved me so much work :)
if i had had my choice of $500 vehicles it would have been a '68 Grumman-Olson

why would you say that?
 

see here in the US some states
dont have vehicle inspection, and for many
years most states didnt have smog
requirements. we can run pretty much anything we want ;-)
i got 30 year old VW A1*s to do 60 and 70 MPG respectively
and a benz to do 40.
i'll make this one shine too.

this truck was routinely carrying more than a ton. its rear leaf springs
are permanently inverted!!!

where in Belgium are you?
when i was a kid for a short while we had some real estate
in Antwerp. interesting 2 story commercial prop.
garage downstairs, residential upstairs!

will do air dam, no side skirts as i am looking to implement a zero lift/mass airflow diffuser to work in conjunction with the relief duct. yes, dome is planned, and so is a kamm.

so, what is wrong with a duct?

oh. you mean like gettin it running :=)

thank you Robert! i found it just the other day, saved the link, of course not to be retrieved when i needed it ;}

your kidding. that looks like the top of a camping table ;~| actually i want the flat wall in order to establish a status quo mpg. then i will fit a slanted board, and then a rounded capsule all existing objects i hope to find.
then the duct and if it shows promise i will marry it to a carefully designed
cabover bubble.

yes to front end tray. it has twin i-beam, very busy design. from cab back i am going to clean up the frame and even remove the cradle which housed the slide out moving ramp, delete the 30 gal cube fuel tank in the rear blocking airflow, generally streamline frame members as much as possible, add a tubular rear bumper (it has none) and attempt to give it a favorable trailing edge.
wheel pants for the dualies but instead of side skirts i am going to encourage more air to flow towards the center of the underside to generate mass flow for this hybrid diffuser idea which will hopefully get the duct motivated!

just doing the injectors should bring it up to 10 mpg

a properly designed turbo system can be used for power or economy - your choice. i have some tweaks in mind for my turbo vehicles that will utilize turbos aftercoolers and water injection in a whole new way.

wont alter the cube shape, will add to it though. ideas?

alignment like EVERYTHING else on this vehicle is likely in a state of disrepair.
thanks for the tips

thank you for the comparison, very valuable. your tuck was likely a DI run by a computer so it would have done better than mine. how much load did you have, and hills?

went to a fair not long ago, visited a big craporate Ford display showing off all their new offerings. as part of one of their displays they offered this DIRECT comparison. 1) Dodge Sprinter 2) Chevy HHR 3) Ford Transit Connect.

tell me please, by which means are these 3 vehicles even remotely comparable
the rubber tires they ride on?
this is NOT a joke!

lowering, no. too much work/money. good idea though! i have found reducing profile helps quite a bit even if frontal area is only reduced marginally!

LOVE your bville type trunk lid wing!
 

i do my own work already have parts. actually it will be fun, have some great ideas for the engine already.

have you done anymore work with your wing or kamm?

power service
 

i see this aero thread has turned into an engine discussion, i would deflect future posts, but believe it or not there is no engine forum on here, strange - no?

Ryan, i dont know the compression values yet. 2 cyle oil will do little for lube.
Power Service lube additive, who refused to pay their part of lab testing during a shootout of lube additives actually REDUCED ulsd*S LUBRICITY.
members of the forum which conducted the test actually had to pick up the tab for power service. pathetic!
yep i had a buddy which had a Ford truck with a broken crank - worked fine.

Mixer
 

great idea, there are 2 lovely Mixers shuttling around town featuring side mounted roots type blowers, perfer turbos though. would your backyard big enough to keep it ;~>

it wont take me much money, i agree it should have had a turbo. the factory turbos which were becoming available a that time were purposely so severely flow restricted to prevent the diesels from showing up Ford*s 460 big block gasser.

the box height is needed, and there is quite a charm to having that much headroom. the truck will double a shop/living quarters at times.
yes, contemporary boxes ride much lower on the frame, but oh well, make the challenge more enjoyable!

Generally it doesn't do much but has a large space and cost penalty, it can even hurt things if it is not implimented perfectly, for the gain I would think it not worthwhile.

Love the vehicle! The paint job is awesome! Lowering the truck, an airdam, belly pan and diffuser should help quite a bit. Regearing might help depending on what RPM you are running at your prefered speed. Good luck with the project. I will be following this one. The lessons you learn could be applied to a lot of box trucks that are on the road!