Ecomodding by Cadillac - Fuel Economy, Hypermiling, EcoModding News and Forum

AeroModder · 05-04-2010, 10:28 PM

I was inspired by the taillights on 90's Caddys for a kind of a partial boattail. I noticed the rear end on my Tempo is slightly angled inward, and I decided to extend that angle out to the edge of the bumper:

As you can see, I cut out a couple sections and covered them with clear packing tape so the brake lights can be seen from the side. I don't know if you legally must have at least some reflective red lighting on the side or not, but just in case, I didn't want it totally blocked.

I also added mini-spoiler like extensions off of the top and bottom edges to better detach airflow, but I'm not sure how much it will help.
I'll be testing the effects of this tomorrow.

Old Tele man · 05-04-2010, 10:37 PM

...waiting to hear what your before & after "numbers" are.

texanidiot25 · 05-04-2010, 10:49 PM

Pictures of the bumper stickers?

ShadeTreeMech · 05-04-2010, 10:50 PM

IIRC, your rear glass is at a somewhat steep angle. You might benefit more from have a full blown boattail than the sonic the hedgehog things on the rear of the roof.

Now that I think about it i may have just stated the obvious.

Frank Lee · 05-05-2010, 03:52 PM

Quote:

Originally Posted by Old Tele man

...waiting to hear what your before & after "numbers" are.

Don't hold yer breath. This isn't gonna show up in any real numbers.

AeroModder · 05-06-2010, 10:07 AM

The first coastdown test hasn't shown any measureable effects. Then again, it's starting at 45 MPH, so reducing drag by a couple points isn't going to show up much. Starting at 45, I'm still hitting 40 as I come to the Speed Limit 35 sign. Then again, it was slightly cooler, since it was about 6:30 PM, and today was colder than it has been recently.

Though I am starting to think about a way to add a kammback and still keep use of the trunk, since I do use it often. Maybe when I get some money to look at materials that aren't laying around, I'll start working on a design.

Piwoslaw · 05-06-2010, 12:47 PM

Quote:

Originally Posted by AeroModder

Though I am starting to think about a way to add a kammback and still keep use of the trunk, since I do use it often.

I think what you're looking for is Groar's Uglyback?

AeroModder · 05-07-2010, 02:43 PM

I was thinking more of a complete kammback with a hingd mechanism to keep the trunk functioning. He never did post the results of the "uggyback", though. I'd also want to get some clear material so I can still see out the back window.

Even though the coastdown test was unconclusive, I finally was able to reach 150 miles on a half tank. Sometime next week I'll be able to see what my mileage numbers look like now.

ShadeTreeMech · 05-07-2010, 06:11 PM

You could do the full Bassjoos deal and end up with a bigger trunk, too. If I had the money to spare I would totally do a boattail on my minvan and build it to be an auxilary trunk.

AeroModder · 05-07-2010, 07:42 PM

Quote:

Originally Posted by ShadeTreeMech

If I had the money to spare...

There's the biggie right there. I have no money to spare, so I'm working with what I already have on hand for now.

I was going to try another coastdown test, but traffic got in the way. Monday is the next chance I'll get. The way I see it, going out just to test mods just uses up the gas you'll save. Better to consolidate trips and test while you're already out.