Does a traditional square pickup camper shell topper help or hurt drag & mileage?

[crashnzuk]

First pic is when I originally made the air dam. Other two are obviously with the Eagle and the Dodge on the trailer. The AMC really did tow better than the truck even though it didn't really reflect much in the MPGs. My truck ran at 2 psi lower on boost and 100 deg lower on the pyro on flat ground with the wagon vs the truck.
Travis..

[KamperBob]

Makes sense: lower A * lower Cd = lower CdA. Thanks for the update and pi!

[ECONORAM]

Originally Posted by Sven7

Very interested in pics to see how well it filled the wake. Also, I like your taste in cars. So pics of those too if you could

ECONORAM- My dad's car has a trip computer and the average speed over trips is usually in the range of 40-50mph. I suppose it's not the most scientific way to test it, but you'd have to have a pretty long commute to bring that average up to 60mph or so.

That is true.

@crashnzuk, thanks for the pix. Helps paint the entire picture. Good looking truck by the way.

[aerostealth]

I owned the T-100 from new until I sold it to Phil Knox with about 200K miles on it. Ran it with a cab high camper shell for a number of years and we got better fuel economy with the shell on then we did off. Baseline was 25 mpg from the manufacturer. It makes sense to me that instead of having two wakes, (1: behind the the cab, and 2: a second wake area behind the tailgate,) that having just one wake area, albeit a larger one, would be a less disorganized chaotic state for the truck aero. We experimented with half bed covers, dog houses, and wings and they all improved the mpg.

[ECONORAM]

Aerostealth, I think you may be onto something. I've had a topper on my truck for 5 years now, and took it off earlier this month thinking we'd see better mileage. A 1,000 trip to IL and back says nadda, at least at a glance. Seems to be the same. Haven't crunched the numbers yet, but the only think that was obvious was less weight going up hills. I freely admit the truck looks better with the topper installed.