The Cost of Learning (aeromodding a Toyota pickup)
 

Ok, so I've been a Ecomodder lurker for some time now an all I have really done is adjust the nut behind the wheel. now I'm commuting to and from college (15 miles twice a day) four days a week an my budget is tight... Fine I'm cheap an I've been thinking about a few mods for my vehicle a Toyota Pickup, 4 cylinder, 5 speed. Its my baby! :turtle: I've gotten up to 30 Mpg highway on long trips, but back to mods. I know that the most beneficial mods are in the back like a aero bed cover, an boat tails. but they are not in the budget right now. So I've been thinking I should try a set of rear wheel skirts an track my tank to tank mpg to see improvements. What should I make them out of? how should I attach them? I've been thinking I should make a cardboard prototype an use duct-tape. But I'm also concerned about looks too, so I was thinking of painting, but if I'm going to do that why not do it right... Right? :confused:

I made mine out of an election sign.
I used screws and bolts.

I used cardboard first as a template and then cut the plastic sign to match. Then I spray-painted to match the color of my car. They look ok and have been on there for almost a year now.

I learned a lot from using the search feature and looking at how other people had made theirs. Other than that, I just attacked it and figured it out as I went along.

I don't have any election signs that I can get my hands on, but I do have a lot of cardboard an thin wood strips that I can use to make up a sturdy design. thinking a coat of paint and poly would seal the deal an keep water out while looking good. I may be able to rig something up so I can secure bolts on my skirts an just use a wing nut or something of the sort so it has an easy on/off capability. Thanks for the ideas, I'll look into materials tomorrow since I have only one class tomorrow. Seems like a waste driving down for just an hour an a half class, but it is what it is.

I honestly think you could do this pretty much for free if you wanted to, scrounging waste wood for a frame, used sign material for the skin. No?

Yes you are right. :p I actually have two large cardboard panels I've made for an aero shell but for one I didn't think that cardboard an wood strips would hold up to highway speeds for that large of a project. Also I'm on my dads insurance right now so he's worried about a blind spot an when he says no he means no. So I'm starting on something simpler to get the feel for it. I'll work my way up to a tonneau cover. :turtle:

Speaking of which: an actual tonneau cover isn't as good as an aero cap , but better than an open bed. Also easy to make with scrounged materials, and should meet with dad's blind spot approval.

The aero cap is later to come I've been on the lookout for old windows people are throwing out so I can snatch some glass an have it cut for a peep hole then I will be able to go full out on the aerocap. but if not 'Ill have to go with the half tonneau.

glass
 

Any glazing material which goes down the road must be DOT rated.
Residential window glass might get you in trouble.
Keep your eye out for some sort of Plexiglass/Lexan for the peep hole,as they're both certified as replacement DOT glazing.
I've used discarded skylights which had a defect and just cut good material out.
If you put masking tape on the plastic,mark your lines and cut,you won't scratch the material.A sabre saw or bandsaw works great.

Second to what aerohead said.

I get cut-offs from the local hippy recyclers. for instance triangles of 1/8" ABS 42" on the short sides (US$4ea). If I could find an old satellite dish to use for a slump mold, that would be great. If you had the dish, you could just cut that up.

Or you could drill a hole in a disk of aluminum sheet, chuck it up and spin it in an improvised English wheel, or clay on a potters wheel. It would make something like a big Moon disk with a hole in the center.

Then cut it in half and trim each half to the shape of your wheel well.

I know its been a while since I have posted anything to the thread, but due to the cold weather I've been getting about 23 out of my truck and it hurts after seeing 26 in the warmer months. So that pushed me to buy materials for a tonneau cover, two sheets of 7/16 OSB, and various washers, nuts, screws, and bolts. I plan for it to be removable, and light but strong enough (may have to put ribs on the underside) to withstand the wind. also saving a few bucks and having some fun with this project I plan on forging my own "L" brackets to secure the cover.

Have you done a grill block? Thats a great place to start for aero and warm up (especially in winter)

I've ran a goofy lookin cardboard one on my truck for a trip but nothing serious yet. Still haven't decided what to go for, either pipe insulation or coroplast. could just block the radiator with cardboard did that last year when I didn't keep track of MPG.

Blocking the radiator alone is OK for warm-up, but may not help much with aero, since you've permitted air into the "aerodynamically dirty" path to the engine compartment.

The goal is to only allow in as much as you need for cooling, and send the rest around the vehicle, where the aero penalty is lower.

I will focus on the grill block after I get the tonneau cover squared away tomorrow I have two panels cut out that fit well together over the bed. Tomorrow comes the hinges and attaching them to the truck. :D :snail:

Oriented Strand Board should be thoroughly waterproofed.

I plan to poly and paint but I want to get everything squared, situated, and tested. then red to match the truck and a black racing stripe would look sweet! :turtle: :D

Ok, so I got the cover all cut out and spent last night working on making it fit right. The cover is pretty simple just two 60"x37.5" sections making a 60"x75" cover that folds in half and is able to be picked up by one person and fits between the wheel wells if I need to haul anything. I put one coat of poly on it and once it dries I'm going to paint it to match the truck and put a racing stripe down it for looks. :turtle:

So I have been working on my tonneau cover for the past three days. I put a coat of poly on, two coats of red paint an the black racing stripes, now all that is left is the last coat of poly. I finally took some pictures this time and I think the cover looks rather nice. I'd like some opinions on how the cover tuned out. do you think it will improve aero vs an open bed? I may add a kam to the truck cab so I can improve aero a little more but I cant block too much or I cant see, and I don want to go full aero shell (yet).

Definitely will help with aero vs. an open bed. That's well understood.

Counter-intuitively, a "half tonneau" would be even better, though arguably more difficult to make, plus utility goes down. Search the site for that if you're interested.

Thanks for the feed back Metro, I know full<half<aeroshell<redesign in the drag reduction department. I've done my research like a good lurker haha. But covering just half the bed didn't seem like a good idea to me I figured I'd do the whole thing. But I can add two more brackets an unscrew some screws and easily take off the front half to make a half tonneau. I may try that next tank. right now I'm at that stage when I wonder if the mod worked (no scangage or other instant feed back) But I did notice that driving with dew on the cover when I got to 30-35 the beads of dew were pushed back and out from the air pressure and it was on the back half of the cover.

aero
 

GM's patent drag table indicated a 5.6% drag reduction,and Ford's testing indicated a 7% drag reduction for a full tonneau.
So maybe 2.8-3.5% better mpg on the highway.More the faster you drive.

Darn I was hoping for ~4% but I don't drive nearly fast enough to get that out of my set up. :turtle: I'll rock the full cover for this tank and may try going for the half on the next. If its not enough ill add a Kam back to the cab that will bolt to the cover for extra aero, but probably a cab wing for testing. well it is what it is. If the air don't like it, it don't like it.

4%
 

*The 1/2-tonneau will get you the 4%.
*A little better with a blister
http://i1271.photobucket.com/albums/...ohead2/201.jpg
*A crude wing/sail panel added gets some extra mpg
http://i1271.photobucket.com/albums/...ohead2/206.jpg
There are a bunch of varieties and combinations,even inflated tails
http://i1271.photobucket.com/albums/...ohead2/208.jpg

I'm going to have to try the wing/sail and half tonneau combo in the next tank or so. I kinda like the looks of it. But before I do anything else I should go for the grille block and finish my rear wheel skirts. (The frames have been sitting around for a few months)

I know you have it already made and painted, but I see tonneaus on craigslist by the handful every time I check. Pretty cheap too. I got one for $100. I see 'trifold' models too, which might allow a partial tonneau effect to be achieved.

As for their effectiveness relating to fuel efficiency; I must admit that my experience has been that it has little to no effect. I do a fair bit of highway driving, which is where gains should be seen, but I'm not seeing them. The best thing I can say about my tonneau experience is that it keeps all of the crap in the bed from blowing into the cab when I open the sliding rear window. :o :(

Even with paint and materials I spent $52 about half what the covers you see go for and I got to make it how I wanted and weights no more than 40 lbs. it folds to lay in between the wheel wells so I can take off the 6 wing nuts and stow it if I need to haul. The cover is in two pieces so I can take the front off and go for the 1/2 tonneau for testing. An each vehicle is different so I don't know how it will affect my truck. :confused:

Sounds like a well designed cover! Cheap too. ;) I'll be interested to see if you notice mileage improvement.

Your fuel log shows an encouraging trendline -- up to date?

My first thought: air bag for rear-enders, what a great idea!

For the OP: I'm surprised you're only getting ~23 mpg out of your truck. From the picture, it looks like a 2WD, no? But I get around 26 from my '88 4WD, and that's including a lot of load hauling & driving up rough mountain dirt roads.

Oh sure, make me feel guilty on Christmas Eve. :p Not up to date. It leveled out at a steady 21-ish MPG. Tonneau did not make a noticeable difference but it could have been that they were starting with the winter gasoline in my area. I'm averaging 19-ish these days. There is a thread on one of the Tacoma forums saying that pulling the intake hose that connects to the fender well (cold air source) can show gains, but I have not tried it yet.
Is yours a 4 cylinder or 6 cylinder? I have a friend with essentially the same truck as mine except manual transmission and 4 cylinder engine. He gets 27-ish. He knows all about hypermiling but claims not to do anything excessive in the truck. (We both run the tires at 40psi.)

Yea its a good design but with the day and a half of steady rain and wet weather I found that I did not seal the OSB as well as I thought and had to take the cover off to dry and prevent further cracking. The edges are swollen slightly and the paint has cracked slightly. So once it dries out ill have to take my Christmas money and invest in some more poly and let it properly dry and cure this time :/:confused:

An Merry Christmas to those of you that celebrate it and Happy holidays to everyone.

Highlights the problem of trying to evaluate mods with tank-to-tank comparisons (especially mods that may make only a modest improvement). Small changes disappear in normal variability from outside factors. A-B-A or coastdown testing is best.

Oops, guess my memory must be going. I was sure one of your first posts said you had a 4-cylinder. And of course I assume any truck is a manual :-)

Oriented Strand Board is not fit for purpose. But since you're at the 'plenty of money to fix it later' stage—compare the costs involved for your 'poly' product and a quart of Plastidip and a disposable roller.

Yea I realize that now, should not have gotten OSB. :( But I do have some poly left over so ill have to do more coats. :/ Now the question is is it worth it to keep fixing the problem or starting new. :confused:

It was prescient to title the thread 'The Cost of Learning'.

I looked back but it's hard to tell from your pictures whether there were any pieces bolted together before painting (framing, etc.). If there were, they should have been painted before assembly so the poly (polyurethane?) didn't need to bridge the gap. Location of the damage may reveal something.

What do you think about Plastidip? You could use up the poly on the worst spots, then 4 or 5 spray coats or 1 or 2 rolled coats of Plastidip would make a rubberized coating that would seal everything together. It needs to cure 30-60 day, then it will be more or less immune to nicks and tears.

I actually took the time to drive all of the engine/transmission combinations and permutations before making my purchase. I have a once-weekly long commute and wanted the vehicle to be comfortable enough for that; all of the 4 cylinders I drove were pretty noisy in the cab. In contrast the cabs of the sixes were amazingly quiet - especially after my Honda Fit! ;) I also intend to tow, so the 6-pot was a pretty easy choice. Towing is also why I went with an automatic. Yes towing can be done with a manual, but an automatic is a more natural choice for the purpose. The end result is not the best for MPGs, and I miss my clutch pedal! But it fits my needs.

So it's been a while since I've worked on the bed cover, it's been too cold to put more coats of poly on the past month or so. :( But recently there have been a few 45* days an I put an extra heavy coat on the two pieces of the bed cover. So now it's back on the truck. Hopefully it will hold together and show some mpg improvements. :turtle: