AeroJeep (remote cousin of aerocivic)

[BamZipPow]

Here are my threads on my 1998 Toyota T-100 extended cab that you might be able to use some ideas from...

Modified air dam...
Under belly pan...

[usergone]

Today I went and put the airdam on the truck. It is a very simple design, as you can see in the pics. By coincidence, the bottom wound up at the same level as the lowest part of the rims (the legal lowest limit in texas).

Pics:

Test without sheeting
        1	2	3 (run #)
0 s	60	60	60
10	50	51	49
20	43	43	41
30	39	37	36
40	34

Test with sheeting
	 1	2 (run #)
0 s	60	60
10	53	54
20	46	47
30	40	40
40	33	35
50	29	30
60	25

I couldn't figure out how to use the coastdown spreadsheet from instructables, but the results are obvious. In the first run I would lose about 9 mph in the first 10 seconds, and with the sheeting, I would only lose about 7. The 3rd run was fudged by the GPS turning off in the middle of the run. Go figure.

I could also feel the difference in the foot and see it in the vacuum gauge. Cruising at 50 MPH (yeah, that low) I was able to use less throttle than normal (can't quantify that one, just feel) and saw more vacuum while cruising.

The engine fan kept coming on while at speed, so I wound up cutting out 6 holes in front of the grille. I also need to trim the edges of the pipe sticking out and (if I feel like it) spray paint it.

The front license plate is not mandated in my state, so does anyone think I could benefit from removing it? Aside from the sheeting laying flatter against the bumper, and being easier to fit around.

I'm looking forward to some results from this. I know, I know, I'm not being scientific about this. I removed the P/S belt in the same tank that I put an aero mod on. Oh well.

[AeroModder]

"the same level as the lowest part of the rims (the legal lowest limit in texas)."

Oregon has the same law. It could easilly be cheated with ultra-low profile tires.

[Weather Spotter]

Nice all in one aero mod (grill block + air dam + fix headlights)!

Are you going to make one out of something more solid than the plastic sheet?

For coast down, I just rolled to a full stop and measured the distance. then I figured the % longer it coasted with the mod = % aero gain.

[euromodder]

Originally Posted by thecheese429

Today I went and put the airdam on the truck.

Dunno how strong the plastic film is, but it looks like it'd be easily damaged , maybe even by the edges of the licence plate or the tubing.

Doesn't it affect the performance of your lights ?

The front license plate is not mandated in my state, so does anyone think I could benefit from removing it?

If front licence plates were not mandatory here, I doubt anyone would put them on
If you don't need it, take it off.

Look over your truck to see if there's more useless stuff in or on it that you can take out or off.

[usergone]

As far as the durability, I was thinking that I would use sheeting as a prototype, and re-assess the situation once I see how it holds up. I might look into the coroplast for the lower part and clear plastic for the top.

I'll have to look for a longer stretch of road with less traffic/higher speed limit so I can do some more revealing tests.

[usergone]

I put some side skirts on today. They are just a bar that runs along the side held by two diagonals from the frame. If I high-center, it will bend easily without hurting anything. I should be able to bend it back.

The pic didn't turn out very well (too dark, too lazy to get more light) but you get the idea



The coastdown tests did not show improvement, oddly enough. I lost 9 mph in the first 10 seconds instead of the 6 from last night. I did not record the temperatures yesterday/tonight, so I am sure that is the problem. Or not. Whatcha think?

[euromodder]

Originally Posted by thecheese429

Whatcha think?

Did you test it with the air dam on ?

[usergone]

Yeah, the only difference between this test and the previous test was the addition of the side skirts. I had a passenger, no change in cargo, no tire maintenance. But I suspect the temperature.

[aerohead]

Originally Posted by thecheese429

I have been contemplating my truck's aerodynamic drag for, well, ever since I have had it. I've also been contemplating improving my Cd. My truck's cruising shortcomings became much more obvious after driving a better eco-vehicle than my own.

This summer, I drove my friend's chevy prizm. It was shocking just how big of a difference there was between it and my jeep. It was lightweight, had a smoother engine, and, the best part, was aerodynamic and had low frictional losses (well, it felt like that anyway), oh, and don't forget; it was a stick shift.

Anyway, I was able to coast much farther than in my truck on the same hills at the same highway speeds. I'm sure some of that comes from its smaller tires and that it is FWD, but it also seems much more aerodynamic than my truck.

Getting 30 MPG highway in a cube is not too shabby. Especially considering that it has more than 10 inches of ground clearance. How much farther do you think I could push my FE (highway, of course) with aeromods? Another 30%, I'd imagine (and hope for).

I would like to build a more aerodynamic bed cover than the one I have now. As it is, I may as well be driving an SUV with my profile. I would like to make a full boat tail, that comes to a point, behind the rear bumper. Like this:

(the line on the front is not something I am too concerned with ATM)

(dimensions of my truck are here, and are probably accurate within a few inches. They are just to give a general idea.)


It comes off of the back of the truck in a gradual sweep, is tangent with the tailgate, then ends 3 (or 4, or 5) feet beyond the back of the truck.

For the construction, I am thinking 4 mil plastic stretched over a 1/2" PVC frame. 4 mil plastic because I have a roll that shrinks when heated, and PVC because it is A) cheap, B) lightweight, and C) easy to machine/cut/shape.


This is a project that will be on the back burner for a while, with my schedule filling up again, so I am collecting ideas until I start building, whence this will become my build thread.

I have a few questions. What are your opinions of the profile in general? Should I delete the lower part of the "wing" profile? How would I attach the plastic sheet to the PVC? Other thoughts, etc?

the cheese, unless you cut into the bed box and blend it into the bedcover you're going to end up with attached vortices on both sides of the rear where the fast downwash off the bedcover collides with the slower moving air from the sides.
For your boat-tail section you actually have start from 'scratch' with virtually zero curvature at the tailgate location,then slowly building curvature as you go rearward,both in elevation and plan view.
The only way around it is to cut the rails off the bed and reconfigure them.