Aeromoding my truck ('95 Chevy S10 pickup)

[bennelson]

Hey everyone,

I bought a '95 Chevy S10 pickup truck last week. It is a stock 2.2L engine with 5 speed manual transmission. 2 Wheel rearwheel drive.

I just ran through the first tank of gas and calculated 22 MPG. I was really expecting more than that with this truck.

I have not checked the fuel and air filters yet, although it did just have a new oil filter change right before I bought it.

So, I still have to check through the basics. Once I am done with that, I think I would like do do some aerodynamic modifications.

I think the main thing is that I need a cap anyways, so I would like to do one in the same style as that really nice fiberglass one the Bondo did.

I have zero experience with fiberglass, but was thinking coroplast might work well. It is light and waterproof. The truck is white, so plain white coroplast would match too.

I saw photos of a tiny bicycle camper that appears to be made of coroplast screwed to a light wooden frame.

Seems like that would be a decent technique for a DIY aero truck cap.
Maybe it could also be hinged at the top directly to the cab, and the whole thing flip up when needed to put bigger items in back.

Your thoughts?

[MetroMPG]

First question I always ask people thinking about aeromods: what type of driving is the truck used for? (IE. at what speeds?)

[bondo]

Bennelson,

Wish I had a lid that would fit your S10. Your truck would be a great test bed. Since I am not much help there, maybe I can lend some advice on some possible ways to build your lid.

One method that was crafty was a cap one guy built for his pickup made from aluminum and clear plasitic, (polycarbonate). He sent me some pics some months ago which I cannot find now. He built a subframe out of aluminum angle and thin aluminum bar stock which he bolted and pop riveted together. He then fastened the polycarbonate clear plastic sheeting over the framework. It was sturdy and mostly transparent. I will continue to look for the pictures he sent and if I find them I will send them to you.

You need to plan building your aero cap. Don't be afraid to attempt it for if an uneducated country boy like me can do it, anyone can. Determine what materials you want to use. Fiberglass is messy and dangerous. If you chose these materials if I can afford you any advice I will be glad to. Once you have chosen you materials figure a construction plan and draw it out. Take measurements of your truck bed and in your design figure out how you are going to fasten the cap to your truck bed. This is very important, for at high speeds there are alot of aerodynamic forces exerted upon the cap. An aero type cap creates alot of lift we found out in the wind tunnel tests. Makes sense, it is like an airfoil with the air moving faster over the top which creates lift. I like to think the extra lift counters the added weight of the aerocap itself.

Make sure you use fasteners which will not vibrate loose. Ground vehicles shake alot as you know. That is why I think the aluminum sub structure and clear polycarbonate (which comes in opaque colors, 1/8 inch thick polycarbonate sheet would be fine, you will have have to brace it up quite a bit with your sub structure for polycarbonate is a thermoformable plastic and the hot sun may make it sag) would be a good choice for you can pop rivet the frame together which is less likely to vibrate loose like a bolt will. If you use bolts, always use nylon lock nuts for they stay put.

I would use the clamps (which are made for clamping caps to truck beds) to fasten the cap to the bed. I have four I will donate to you for the cause if you need them.

If I can be of any more assistance, please fell free to contact me. If I can ever lend anyone else some advice on the construction methodologies I have been lucky enough to have been shown by others in the past, I do not mind returning the favor.

Brett

[DifferentPointofView]

Question Bennelson, when did you buy your vehicle?

[bennelson]

I bought it about a week ago, used, out in the country from a private seller.

I was looking for a useful utility vehicle that I could also get decent fuel economy. I always thought that if I ever got a pickup, it would have to be a very small one.

I thought it was a tossup between a Ford Ranger and a Chevy S10, both with the small 4 cylinder engine and manual transmission.

I started looking around on Craigslist a few weeks ago for an S10 at a decent price. The one that I bought had less miles on it that some others for sale and not a super-pretty body, but easy to do a little painting on. So I was able to get a pretty good price on it.

It also takes the same oil filter as my wife's Pontiac Sunfire.

[bennelson]

Here is what I was roughly thinking for an aero-cap:

Light easy to use materials, such as corrugated plastic, aluminum, etc.

Simple attachement to frame. I think caps for little truck like this usually just use not much more than a standard C-clamp.

Top Hinged: Not sure what the best attachment for this would be. I don't think I want to put self-tapping metal screws straight into the cab.

The big complaint I have heard about rigid tonneau covers is that you cant put anything very tall in the bed, and they are too difficult to remove by one's self.

It it is hinged on the top edge, and very light, that problem is solved.

See the attached bad sketch for roughly what I am thinking.

[MetroMPG]

I don't mean to discourage anyone, but the reason I asked about what type of driving you were going to be doing was to make sure you were spending your effort in the right area. IE - if it's going to mostly be a highway machine, go for it. City machine? Won't make as much of a difference.

I think you're right to be concerned about putting the hinges on the cab. One reason: there can be a lot of flex & movement between the box vs cab, and it'll stress the structure if it's firmly attached to both. Best to attach it to the bed only.

You could add stanchions to the forward end of the bed, and fasten the cap hinges to them.

Another thought: while the aero cap gets a lot of attetion & discussion, don't forget about some of the much easier to pick low-hanging aero fruit, like grill block, air dam, etc. - List of aero mods you can do to your vehicle

[DifferentPointofView]

I too bought my vehicle from out in the country from a private seller. Check the fuel filter! The filter that was in mine wasn't filtering at all but turning perfectly good fuel into black rustyness!!! and change the air filter as well. fuel filters are one of those things most regular people never think about, it's always the oil filter and oil they know about, and some don't even look at that either.

U could always hinge it to where it will fold over and sit on top of the hood if you need the whole entire bed. And 2 latches that attach the cover to the very ends of the bed like a trunk (so you can still open the tailgate while it's latched).

[bondo]

Bennelson,

That is a good concept your sketch conveys. It would be easier to gain access to the bed of the pickup and just one person could lift the cap up. I have to agree with MetroMpg about the hinge point being the back top of the cab. The truck bed and cab are independent of each other (except for the Honda Ridgeline) and the two distinct body components flex to the frame independent of each other. This could be a problem.

If maybe you could hinge it at the forward top part of the cap frame itself, opposite the rear cab window, with that part staying in place while the sides and the top stay together and rotate upward about the hinge. A couple of hydralic struts in the right place would help lift it too.

That is the fun thing about design, it always begins with a concept.

Brett

[suchy21]

Does your truck have a belt-driven engine cooling fan? If you do plan on doing some city driving and want to do something with greater impact at low speeds, consider replacing that with an electric one. I spent about $100 for a Proform fan and Imperial fan controller (Both from Advance Auto's website, returnable to stores). I'm seeing a 1-2mpg improvement in my 1993 Ranger, plus the fringe benefits of quieter operation, quicker heat-up (feels good in January), and smoother acceleration.