The Cost of Learning (aeromodding a Toyota pickup)

[aerohead]

Originally Posted by Weber95

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).

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.

[Weber95]

Originally Posted by aerohead

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. 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.

[aerohead]

Originally Posted by Weber95

Darn I was hoping for ~4% but I don't drive nearly fast enough to get that out of my set up. 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.

*The 1/2-tonneau will get you the 4%.
*A little better with a blister

*A crude wing/sail panel added gets some extra mpg

There are a bunch of varieties and combinations,even inflated tails

[Weber95]

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)

[wdb]

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.

[Weber95]

Originally Posted by wdb

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.

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.

[wdb]

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

[MetroMPG]

Originally Posted by wdb

I do a fair bit of highway driving, which is where gains should be seen, but I'm not seeing them.

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

[jamesqf]

Originally Posted by aerohead

There are a bunch of varieties and combinations,even inflated tails

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.

[wdb]

Originally Posted by MetroMPG

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

Oh sure, make me feel guilty on Christmas Eve. 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.

Originally Posted by jamesqf

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.

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.)