Rear deck extension with endplates - ABA results
 

So I just finished up testing the new addition to the rear.

http://img.photobucket.com/albums/v4...E8BFC2075C.jpg
http://img.photobucket.com/albums/v4...9E2DC6897D.jpghttp://img.photobucket.com/albums/v4...D714927CB9.jpg

I tested at both 60mph (constant) and 70mph (constant). Both times, no A/C, radio and full exterior lights on, wet roads after a storm, no rain. 6mph winds out of the SSE.

The test circuit is a 4mi segment separated into a 2mi East->West, and a 2mi return

60mph:

A: WITH REAR MODIFICATION
A1: 51.0, 52.5 =51.75
A2: 50.8, 52.6 =51.7
A3: 51.2, 52.3 =51.75

A Total AVG: 51.73mpg

B1: 51.1, 49.8 =50.45
B2: 50.6, 50.4 =50.5
B3: 50.7, 50.5 =50.6

B total AVG: 50.51mpg

2A1: 51.6, 52.7 =52.15
2A2: 51.3, 53.0 =52.15
2A3: 51.4. 52.6 =52

2A total AVG: 52.1mpg

ABA @ 60mph, WITH: 51.925mpg, WITHOUT 50.51mpg

= 2.8% increase


70mph:

A1: 47.4, 49.2 =48.3
B1: 46.9, 47.2 =47.05
2A1: 47.6, 48.9 =48.25

ABA @ 70mph, WITH: 48.275mpg, WITHOUT 47.05mpg

= 2.6% increase


Not much of a change, but every little bit helps!

i tried this but didn't do ABA. i didn't notice a diff. i had no direction to go so it was all a guess as far as length, angle, height....
http://i110.photobucket.com/albums/n...pse5fdf635.jpg
http://i110.photobucket.com/albums/n...psa550d8a0.jpg
http://i110.photobucket.com/albums/n...ps38280de9.jpg
http://i110.photobucket.com/albums/n...ps53d6d34e.jpg

I tried to take it back to the line off of the template. I think I can probably extend it another 3in or so...

http://img.photobucket.com/albums/v4...11.31%20PM.png

I should have used a method and might have seen good results. good testing BTW!

Thanks for posting. I love the look of pro-stock spoilers and one that get better MPG look even better :)

How did I miss this test from 2015? I tested an effort at a somewhat similar "box cavity" in 2013. But like deejaaa's effort in post #2 above, I kept mine close to the bumper extension for "legality." It did no discernible good (or bad) in my ABA testing: http://ecomodder.com/forum/showthrea...tml#post376489

The one in this thread saw a +2.5% improvement by coming very near to filling out the aero-template profile.

In the link you provided, looks to be a simple clean edge for the air to release from, and no filling out of the aero-template profile.

Fair analysis?

Yes, that's right. I was trying more of a "box cavity" scale, which professional testing suggests can offer a modest benefit. But the design matters a lot since the box cavilty will interact with other mods. There is little room for error. Also, I was sill pretty new at modding and testing (it was 2013) and I did not fully account for the imprecision of my gauges. For all I know there was a 1% benefit that I could not detect.

But this thread's mod has some cool results. The only problem is that it is not legal to extend beyond the bumpers or obscure lights. I was hoping to "hide" my mod with an "aero bike rack" sticker on it. This bigger mod would be harder to "hide" that way.

The OP has not posted in almost a year. I wish he/she were still around here.

Federally or locally? I looked up laws and such and it seems okay as long as it isn't 4 feet past the bumper, and then it requires a red flag...unless I'm looking in the wrong place.

Only thing on my tail extension mod that's obscured is the taillights in the trunk itself, and even those are barely covered. I took out the bulbs just to play it safe and make it appear that there are not supposed to be any bulbs there in the first place.

Had a cop following behind me a mile or two to work today but didn't pull me over so it apparently passes the cop test.

While we are on the topic, never put reflective tape on the back of your car or truck as a back-up safety enhancement. It could get you the wrong type of attention.

I had some on my tailgate once and a cop pulled me over to claim that one of my taillights was dimmer than the other. No ticket, just a pain in the butt to deal with.

Don't give them any excuses, they get bored at night apparently and that reflective tape let's them see you a mile away.