AeroRanger (brother to AeroJeep) boat-tail

[cons]

We found a small yard sign of coroplast, but that's it for now. That'd be funny to make it out of political signs.

[usergone]

Originally Posted by cons

We found a small yard sign of coroplast, but that's it for now. That'd be funny to make it out of political signs.

Especially if you got signs from all parties in your area - and kept them showing when installed.

[aerohead]

Originally Posted by cons

"One thing you should know is that I'm at high altitude (~7000 ft average).
That definitely plays a role as it effectively turns my 3.5L engine into a
2.8L (there's about 21% less air up here...less air means less fuel) and it means less wind resistance." From 5speed5 today

If true, me being at 6,500 feet turns my 2.3 into a 1.85L engine, helping to explain to me why these numbers seem a little too high.
I've heard you can't even throw a curve-ball at high altitude because the threads don't get grip on the air. I've asked others out here who say they get way better mileage up here too.

SO, these numbers seem way high. I don't want fellow ecomodders thinking I'm full of BS. I would be a skeptic hearing about a truck doing 60 mpg.
But remember, I think altitude plays a big role, and these 60 mpg are under pretty ideal conditions on only HWY (roundtrips uphill and downhill, upwind and downwind).

It might not be that out there for a small truck with a small engine.

cons,sorry just getting back to town.
I'm in agreement that short test runs can be problematic as to accuracy.
I'm also in agreement that EFI is probably 'smart' enough now to lean mixtures at altitude whereas in the days of carburetors you might have to re-jet to avoid rich conditions.
Somewhere,I did a thread on elevation vs air density which may help on that issue.
If you have an established baseline mpg at say,a constant 55-mph ( forget EPA numbers ) you can do your comparisons against that realizing that weather and road conditions will affect it.
If you're going to do your testing at 55-MPH,then there is a relationship already established which you can use to reverse-engineer your new Cd.
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A 10 % drag reduction will net you a 5 % mpg improvement at a constant 55-MPH ( no stops! no messin' around! ).
If say the Ranger originally had a Cd 0.44 like my T-100,the if you were to streamline it down to Cd 0.12 ( like GM's Solaraycer ) that would get you down to only 27 % of the original drag,a 73 % reduction.
At a 73 % drag reduction,this should improve MPG at 55-MPH by half the percentage,or 36.5 %.
I'm not sure what the Rangers original baseline would be at a constant 55-MPH,but say it was for example, 27 MPG,then the Cd 0.12 would get you 36.85 mpg.

[cons]

Thanks for the input Aerohead. I've just driven cross-country and have a great idea on what the truck gets with all my life's load in the back and in the cab. I'm guessing it's around 700 pounds. Don't know how much of an effect that should result in.
The first day, there was no wind, got 39 mpg on 15.7 gallons, usually going 60-75 mph, but had a slow construction zone for an hour. Went from 6,200 ft-4,000 ft
2nd day, 15.5 gallons, removed grill block due to it being a hot day and big load, got 34 mpg, at 65-75 mph, down to 2,000 ft.
3rd day, 14.3 gallons, 37.5 mpg, did the grill block for the second half, crazy cross wind, down to sea level
Then went 75 mph purely for 4 gallons, got 22.7 mpg, bad crosswind, hard rain, lights
Then purely 60, needed headlights, wipers high speed due to hard rain, bad crosswind, 37.1 mpg, that difference seems too big.
4th day, 14.9 gallons, 34.7 mpg, very stiff head wind all day, constantly watching the flags to verify that direction. It sucks, I only had a tail wind for a couple hours on the second day! And I went from west to east!

These were not ideal conditions (warm and calm would've been great). Also huge load (I'll put pics up soon). So to be getting 37 in it wasn't a big disappointment. But I'm still really curious on those 60 mpg runs.

Did some coast down testing in Jackson before the trip and used the tool here for that. Seemed to be around .24 to .26 on the graph. Factory is .49

My tires are at 38-40 psi (max is 44), might have gotten lower due to the colder temps and coming down from the higher altitude. I don't know how much that would effect the long drive. Also, the load in Odd is so heavy the boat tail is at least a foot lower than it was pre-load. That might have thrown off my angles a little. Going on a sailing trip for the next month and might not get in a good long highway run to see how Odd does, empty, at sea level. But I might be too damn curious and have to try anyway.

People at the pump were always stoked to see Odd, and I direct them all to this site. Cheers to this site!