how to drive my cube van

[MazdaMatt]

I have a 94 Ford F350 chassis with a 20' (that's big) box on it. I use it for hauling my race car to the track because I can sleep in it and the car is out of the elements.

This thing is HORRIBLE on gas. Not only is it a rolling brick (it has a bubble on the box over the cab, but still). It has a 7.3L non-turbo deisel V8 and a 3-speed transmission that shifts by RPM, not by engine load (so i can cruise at redline in city traffic for some reason). Redline in 3rd gear is about 115km/h.

I learned that I can get about 30-50% improvement by going 90 instead of 115.

How the heck else can i sqeeze mpg out of this thing? I try to only stop once at stop signs and I try to time lights. If i try to coast it slows down SO fast that it isn't worth coasting.

HELP ME! It costs me about 100 dollars in gas to go to a race track, then back to the shop.

[dann_04]

hmmm... it sounds like there are some mechanical limits to your fuel economy there. I would say see about aeromodding it as a cinderblock on wheels isn't a good desing. The slower you go the better. If you let off the pedal it doesn't shift up? If that is the case i would say just go slow and accelerate gently. What kind of fuel economy are you getting out of it currently? Also is your engine tuned well, air filter clean, tires inflated higher than reccomended, a/c off(if equipped), fuel filter not gummed up(sometime a problem on diesels) that's all i can think of at the moment.

[MazdaMatt]

I only drive the van 3 times per year. I chose to do 3 double-headers for my required 6 events so I could save on travel costs. I understand that racing uses gas. I'm here to learn how to use LESS gas while still enjoying life. Can't drive the car there, it would recieve so many infractions if i drove it on pulic roads that the police would just shoot me to save paper.

I was thinking about undertray and side skirts, but that may be hundreds of dollars in sheet alum. Thinking about a narrowing rear (since my door is fold-down, it would attach to the door), but that would have to wait since i don't have much chance to work on the truck. As for mechanical state... its decent, but could be better. Current mileage, i'm not sure. I don't use the AC in the truck, but i'm sure it wouldn't matter with the big deisel.

Letting off the gas does not shift up. I could be going 1mph below the "shift point" for an hour and it will not shift regardless of throttle position. That does mean, however, that i don't have to worry about silly down-shifts.

[lovemysan]

I'm going to guess that you use 60-80% throttle to get to cruising speed. Stay under 50mph. 35mph would be near optimum.

[MazdaMatt]

my next trip would take me 6 hours in my car at "regular" driving pace. Doing 35, i may need to slot in time for a couple birthdays.

Do you think I'm better off doing 90km/h on the freeway, steady-speed? or doing 70km/h on country roads that go through towns where I'll be hitting stopsigns now and then?

[dann_04]

I'd say do 80km/h on the freeway and stay right if at all possible. With a car in the back of that heavy monster inertia is your friend. Adding extra stop and go is the worst you can do. try 85-90 with easy steady acceleration. how are your tires inflated compared to the max allowable psi?

[MazdaMatt]

I believe they are a little under max, but before that trip i will top them up to the max. I wouldn't go higher because trucks are more likely than cars to be stopped and checked for safety stuff, and from what I see in the media, they are thorough in this province.

[justpassntime]

I know this is a lot of work but here it goes anyway.

You could change the top of the van. Chop the top and tapper it towards the back. It could even be so drastic that you would need to raise the roof to get your car in. Kinda like a super size pop up tent trailer. It could even be done with hydraulics like a car carriers upper level. I know it's crazy but I always seem to have extreme ideas. It would be cool no doubt, all the other racers would want one. You could even post your mpg on the side of it. LOL

Put a deflector at the front to help guide the airflow over the blunt nosed front.

Have we talked about Airtabs?

[MazdaMatt]

havn't talked about airtabs because nobody seems to be able to prove their worth in other threads. They seem to be expensive too.

Yeah... i think that sort of structural change is a little more costly than my 1.44/L deisel! If i was a little less sane, it would be worth it. I could shape the whole truck like an aerofoil.

Maybe if I later sold the truck and bought a regular pickup and trailer, i could build up walls/roof on the trailer in that fashion, but that's just extreme.

[skyl4rk]

How much traffic is there on the streets you will be driving on?

Can you put the vehicle in neutral while rolling?

Do you have the ability to shift at all? What does your shifter look like: P - R - N - D - 2 - L ?

[trikkonceptz]

Can you post a picture of the vehicle, it could help us help you ..

[bhazard]

a 94 should have an OD trans...

[lovemysan]

Originally Posted by bhazard

a 94 should have an OD trans...

I was thinking the same thing. But depending on the axle ratio it could still only top out at 65-70mph. I drove a f450 that was geared similarly. You could sell that van and buy a bread van with a 4 cylinder cummins 4 bt diesel. I'm told they get around 18-19 mpg at 55mph. Thats top speed at 2600rpms I believe.

Personally I'd try to save the easiest portion of possible savings and spend the rest of my time trying to move more product. You could also do a little freight hauling. There's a website where people give and receive bids for shipping items like water heaters, mowers etc. You could haul a little extra stuff and make up some fuel cost.

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[lovemysan]

For some strange reason I thought you used the van to do some type of sales at an event. Someday I'll learn to read. I don't think a bread van will hold a car.

[Tony Raine]

ok, this is pretty extreme, but......

cut down the box (especially the bubble top) to a more aerodynamic camper and parts/tools stash only. then haul the car in a smaller enclosed trailer (just enough for the car). aeromod the truck and trailer as a unit.

[MazdaMatt]

Okay, lets just reality check for a second here... I drive this truck to 3 events per year. A 2-hour trip, a 4-hour trip and 6-hour trip. I won't be doing any extreme modifications and the purchase of an extra trailer is a lot more than the entire gas expense of these trips. I'm just looking for some driving tech. This thing is BIG... doing mods to it would cost thousands of dollars.

The tranny is a 3-speed because it used to be a Hostess delivery truck. It was never meant for highways use. This thing handles GREAT in the city, even with 3000 pounds in the back. I am sorry, but I don't recall what the tree says... i think you're right, PRND2L, what could I do with that to help me?

As for coasting in N, that sounds scary to me with a 6000 pound weight rolling down the road... it isn't a metro.

Making up some money with some work on the side would be great, however this truck is insured as a "personal" vehicle so my rates are very low compared to a mover's. If it was discovered that I was hauling something other than my race car (condition of the insurance) I'd lose my coverage. Also, replacing the vehicle is a no-go because it has already been set up with a fold-down ramp door and die-downs for my car.

I'll try to get a pic posted. Its a big ugly beast.

[Tony Raine]

yeah, i figured my idea would not be feasible. but hey, someone had to throw it out there, right?

sounds like you already found your #1 way to save gas (slowing down).

hey, if you win more $$ at the races, you can use that to "save" on gas

[MazdaMatt]

Haha... these races have prize pools of synthetic oil, tires and safety gear. I'm not a pro racer.

I think i basically just have to stick to the highway and drive as slow as i can while remaining awake and not disrupting traffic. I'll get my air filter checked out. I'll also see if i can do ANYTHING for the airflow around the bottom and back of the truck.

[trikkonceptz]

Neutral coasting shouldn't scare you. We are not asking you to drive down mountains in neutral, your tranny does little to brake your vehicle unless the vehicle has some type of exhaust braking system. If you drive on level ground coasting to lights you should see a benefit in the tank, hopefully you shut it off when at a complete stop.

Also large trucks like yours should have proper tires for the load you are carrying, therefore inflating them to the sidewall max should also be a non issue especially since ride quality goes out the door. PLus it should extend the life of your tires by not bulging the sidewalls and reducing heat from friction. Those 2 alone should be enough for a mild bump in your beast.

On the aeromod side I don't know if side skirting the truck will be a benefit, but instead of using aluminum paneling which is expensive, consider Choroplast sheets, which are lighter, cheaper and can be braced with aluminum rods to the chassis for additional strength.

Once you get pics up I'll throw some more ideas at you ..

[MazdaMatt]

Ride quality was MUCH improved when I bumped up the tire pressure, actually. The biggest improvement was steering feedback and not acting quite as much like a sailboat. Yes, i gained some FE when i bumped upt he tires as well. I did not, however, put them to sidewall max, so i will do that next time I have my hands on the truck. This thing rides so smooth it doesn't need cupholders. You just put your coffee on the dash.

Simply dropping throttle brings the revs down to idle and allows the truck to coast. I would fear for the health of the tranny if i kept popping it from N to D.

In the drive from the shop to the highway I only see 2 lights, and from the highway to the track it will just be stop signs, so unfortunately i won't see any benefits from turning the engine off. Don't these big deisels idle on fumes (figuratively) anyway?

Is a MPG read-out possible on this thing? Anybody know the 1994 7.3L Ford engine?