1960's truck aero modded? - Fuel Economy, Hypermiling, EcoModding News and Forum

Tulok · 07-17-2016, 03:33 PM

So, after my suburban aero idea, I decided to not do anything to it. it got decent enough mpg just by being tuned up and having the tires inflated to max sidewall psi. and when I upgraded to 35's, I used the stock wheel which tucked the big tires in nicely.

Anyways, I am going to start on a new project here that is much much larger and Im much more willing to cut, and weld and rivet all over it. unlike the suburban which was slightly restored and just in too nice of condition.

this is not the one I'll be getting, but it looks very similar. but mine will not have an extra wide flat bed with a headache rack. its just a flat bed with boxes underneath.

1960's GMC 4000. 305 V6. 4 speed manual with 2 speed rear end. it's also using single rear wheels, thankfully. I dont need a dually. I may change the engine for a small block chevy 350, or a caddilac 500 that are further detuned for extremely low rpm usage. I have been searching for BSFC charts for either one.

So i want to build a stake side that is in a kamm back shape, add wheel skirts and deflectors. remove the front windshield visor. aero-ize the bumpers. Lower it a few inches. etc. I'm open to all ideas. I will be constructing everything out of thin sheet metal or wood. I want it to be very extreme and i'm not opposed to cutting anything or adding anything for the sake of aero.

Other things like putting clear plastic over the grill and headlights or just making a flat metal piece to block it all. and the "hood vents"

Ill also be removing the huge mirrors and putting tiny little 3" circles mounted on the door.

I am very curious about using the exhaust gas flow to maybe promote a bettter airflow. especially with a large engine pumping a lot of air, would stacks with the exhaust pointed into a Kamm-Back airflow shape help? Or maybe have the exhaust go into a plenum then divert it under the vehicle to help air flow around the massive rear axle and drivetrain pieces?

that also reminds me of this question: Would putting a tear drop shape on the back of the axle tubes help much? would it be better to have an air dam that goes close to the ground, or would it be better to build a flat bottom on a truck of this size?

I do want the large pieces to be removable out back so i can tow a 5th wheel.

I'm still researching other mods like hot air intake, an extremely mild camshaft. electric accesories etc.

I can do a lot of custom metal work easily, and this is the perfect platform to work off of. The cargo capacity is not that important to me. I'll be building a severely oversized stake side setup for hauling trash to the local dump. the aero setup will be for my own satisfaction, and hauling things like engines and chassis parts between cities.

THE COMPLETE OPPOSITE OF THIS:

kach22i · 07-17-2016, 03:50 PM

Interesting project, the scale of it is most imposing.

Aesthetically speaking I think you would be better off with one of the cab-over designs from the same era.

I saw one at a car show last summer which had been lowered and was just begging for a jelly bean teardrop back to be added to it. It too had a flatbed.

Tulok · 07-17-2016, 03:57 PM

@ KAch. thats very true. the cab over would look amazing. I just refuse to even ride in a cabover. too dangerous in an accident.

kach22i · 07-17-2016, 04:23 PM

Quote:

Originally Posted by Tulok

@ KAch. thats very true. the cab over would look amazing. I just refuse to even ride in a cabover. too dangerous in an accident.

The cab-over at the car show which I tried to find a photo of unsuccessfully, was perhaps higher than you are thinking of, even when lowered.

The legs of the cab-over driver would be above the roof of most cars, and driver's feet in the windshield height area of most larger SUV's.

I'm not talking VW van scale of vehicle, it would be in the same class as what you are looking at now - BIG!

Tulok · 07-17-2016, 04:56 PM

Oh, you know that would make sense. I didn't even consider the fact that these trucks are so tall. There may have been a cab over and the same place I was looking. I'll have a glance around when I return and see if I can't find one instead. That would be beneficial to me as well because I'd like to have as long of a bed as possible on the shortest possible wheelbase.

freebeard · 07-17-2016, 09:08 PM

Quote:

I do want the large pieces to be removable out back so i can tow a 5th wheel...The cargo capacity is not that important to me. I'll be building a severely oversized stake side setup for hauling trash to the local dump. the aero setup will be for my own satisfaction, and hauling things like engines and chassis parts between cities.
....
I'd like to have as long of a bed as possible on the shortest possible wheelbase.

The COE would only add frontal area; better to chop the top. How do you plan to combine the 5th wheel hitch and the stake-side bed? Long bed/short wheelbase would allow more taper in plan.

Hinge a Gothic arch at the rear edge of the bed. It could lay forward against a partial aerocap; swing fore-and-aft for loading and unloading engine blocks; or frame a boatail addition in the aft position.

A friend of mine built a 54 Ford in the 70s that had an egg-shaped cabin on a flatbed with curved sides. Sorry I don't have a pic but it was much like this pickup camper except taller, with a cab overhang and set onto a flatbed.

Tulok · 07-17-2016, 09:15 PM

@ freebeard

your friends truck sounds cool! I like that. and the van with the popout section looks very neat indeed!

the 5th wheel hitch will just be the normal flip up style, I'll have to lift the bed off in order to use it. I plan on using stake pockets and carriage bolts to bolt the bed sides on.

heres what i was working on for a bit. feel free to edit it on paint to make any changes you think would be beneficial. I want to use as much regular steel or wood as possible. avoiding fancy materials.

EDIT:
on this draawing, I have used much lower profile front tires to aid in lowering it,

freebeard · 07-17-2016, 09:48 PM

The truck is long gone; and at the Country Fair this year I learned that the cabin/camper which was up on blocks for years in the Coast Range above Ona Beach had a tree fall on it.

It was in the book Shelter (on page 92, I hear).

The curve you're showing with flat sides would induce vortexes. The top and sides need to balance. It's actually easier for me to take screenshots in a 3D application than overpaint things in Photoshop. Easier yet to recycle old stuff. Here're your choices:

With that long bed and short overhang, you may need to go to something like this:

Tulok · 07-17-2016, 11:04 PM

ok i see what you mean with the sides needing to taper inwards. what would be best way to do it be? I wouldn't want to lose any of the flat bed surface. so would I be better off
doing something like I attached? sort of reminds me of a WW2 bomb lol.

or would that be worse?

I could, make the bed sides fold up or be removeable on the rear corners/side area, but that would be a serious heavy duty project and require some massive fasteners or hinges.

Would rounding the corners with 1 4" radius help much?

What sort of % difference am i looking at between a blunt side, and something in between vs a full on pointed end?

another question is, would a vertical fin help with aero at all? I know it would stabilize the truck, and maybe even help in shallow cross winds? I remember reading about bicycle disc wheels helping in shallow cross winds.