Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 12-11-2008, 03:18 PM   #1 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,556

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.8 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)
Thanks: 3,324
Thanked 6,124 Times in 3,177 Posts
Tested: Airtabs on a mini van, A-B-A - no measurable effect

See also: http://ecomodder.com/forum/showthrea...olla-2390.html

---

As promised, here's the low down on the A-B-A test that I did using my brother's 2005 Pontiac Montana minivan: long wheelbase version, 3.5L V6, automatic.



As I mentioned in the van Kammback thread, conditions were ideal. Zero wind, and no traffic on my favourite testing route, and a cruise control functioning perfectly (unlike the one in my Firefly, which quit while testing the Kammback).

Here's what I did:

1) OEM roof racks were removed, holes covered with tape.

2) Vehicle was driven for approximately 25 minutes / 20 km in sub/urban and rural highway conditions to bring the vehicle up to operating temperature. Ambient conditions:
October 5, 2008 - 18:00
10 C / 50 F
71 % relative humidity
102.5 kpa pressure
0 wind
Cruise control was set once for the entire A-B-A series, at 55 mph / 88.5 km/h. Cancelled with the brake at the end of each run and "resumed" for subsequent passes between the same markers each time. Fuel consumption taken from a ScanGauge II, reset and read at the same markers each run.

3)
4 bi-directional "A" runs were done, averaging 33.65 mpg (US).

4) Airtabs were installed on the top & sides of the van (following mounting instructions on their web site, except they were taped on their leading & trailing edges, rather than peeling off the adhesive backing and sticking them on).

5) 3 bi-directional "B" runs were done, averaging 33.8 mpg (US)

6) Airtabs were removed, and 2 more 2-way "A" runs were completed, averaging 33.92 mpg (US).

Average of all "A" runs: 33.72 mpg (US)

Standard deviation of all the "A" runs: 0.36 mpg

Raw data:

Code:
    West    East    AVG
A    33.8    34    33.9
A    32.8    33.4    33.1
A    33.6    33.9    33.75
A    33.7    34    33.85
B    33.3    33.8    33.55
B    33.5    34.2    33.85
B    33.5    34.4    33.95
A    33.6    34.2    33.9
A    33.9    34    33.95
Pics:

Below are the OEM roof racks. I think those are aftermarket cross bars though:



Air tabs shown - placement only. For the actual test, they were taped across the full leading edge, and on the trailing tip, so they sat flush against the sheet metal:



Side placement. I was advised by the distributor that where the airtabs were set on an angle (rather than perfectly vertically), to increase the spacing between them slightly. So the ones behind the side window area aren't the usual "4 inches on center" layout.


Attached Thumbnails
Click image for larger version

Name:	van-racks.jpg
Views:	2438
Size:	45.6 KB
ID:	2367   Click image for larger version

Name:	van-side.jpg
Views:	191
Size:	58.1 KB
ID:	2368   Click image for larger version

Name:	van-airtabs-back-roof.jpg
Views:	178
Size:	60.3 KB
ID:	2369   Click image for larger version

Name:	van-airtabs-side.jpg
Views:	1924
Size:	52.2 KB
ID:	2370  
__________________
Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now in progress...
Ecodriving test:
Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
The Following 2 Users Say Thank You to MetroMPG For This Useful Post:
Angmaar (06-10-2010), mannydantyla (01-30-2018)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 12-11-2008, 04:17 PM   #2 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,229
Thanks: 17,998
Thanked 5,977 Times in 3,634 Posts
air tabs

Shucks! I was at the store with my fingers on the package of air-tabs when my "Yes Men" monitor brought me news of your testing,so I put them back and grabbed a can of sky lubricant instead. Big thumbs up for the info!
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 12-11-2008, 05:33 PM   #3 (permalink)
TacoModder
 
mobilerik's Avatar
 
Join Date: Nov 2008
Location: San Diego, CA
Posts: 108

rik's prerunner - '03 Toyota Tacoma Prerunner Double Cab TRD 4A
90 day: 29.68 mpg (US)
Thanks: 0
Thanked 2 Times in 1 Post
When you did this test on the Corolla, I wasn't moved much, since the AirTabs site doesn't make huge claims about small cars. They're geared towards big rigs, trucks, and vans. But now you've tested a van. Unbelievable! I really wanted to believe they'd work. I couldn't feel any difference on my truck either, but I hoped it was because I hand-made them. Heck, I still wanna believe they work on something. I think you need to test a big rig next.
  Reply With Quote
Old 12-11-2008, 05:52 PM   #4 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,732

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,571
Thanked 3,507 Times in 2,194 Posts
My hopes and dreams are dashed to the ground. Curse you, cruel world!
__________________


  Reply With Quote
Old 12-11-2008, 06:19 PM   #5 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,556

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.8 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)
Thanks: 3,324
Thanked 6,124 Times in 3,177 Posts
So Frank, I take it that you're in no mood to assist with the next test? I need someone with a mallet & awl to help me put golf ball dimples all over a VW Bug...
__________________
Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now in progress...
Ecodriving test:
Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 12-11-2008, 06:26 PM   #6 (permalink)
rav
EcoModding Lurker
 
Join Date: Sep 2008
Location: albany, NY
Posts: 38

Gas HOG - '08 JEEP LIBERTY SPORT
Thanks: 5
Thanked 5 Times in 4 Posts
Glad you proved it. Now, the bad part is i just got 8 of them delivered today for the liberty. I guess i should now put them on the front under belly pan i made for it, do you think will it help down under?
  Reply With Quote
Old 12-11-2008, 06:45 PM   #7 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,732

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,571
Thanked 3,507 Times in 2,194 Posts
Quote:
Originally Posted by MetroMPG View Post
So Frank, I take it that you're in no mood to assist with the next test? I need someone with a mallet & awl to help me put golf ball dimples all over a VW Bug...
I would be delighted to help!
__________________


  Reply With Quote
Old 12-12-2008, 07:06 AM   #8 (permalink)
Master EcoModder
 
tasdrouille's Avatar
 
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 81 Times in 53 Posts
VGs drag reductions properties are highly dependent on chord placement on an airfoil, you must have placed them wrong *sarcasm*.

Good job for your rigorous testing. Lets hope this puts the final nail in the coffin that VGs do not affect overall drag enough to make a significant impact on fuel consumption in everyday driving of light duty passenger vehicles.
__________________



www.HyperKilometreur.com - Quand chaque goutte compte...
  Reply With Quote
Old 12-12-2008, 11:00 AM   #9 (permalink)
TacoModder
 
mobilerik's Avatar
 
Join Date: Nov 2008
Location: San Diego, CA
Posts: 108

rik's prerunner - '03 Toyota Tacoma Prerunner Double Cab TRD 4A
90 day: 29.68 mpg (US)
Thanks: 0
Thanked 2 Times in 1 Post
Of course, Darin's rigorous testing has demonstrated only that AirTabs have no empirical effect on aerodynamics of light duty passenger vehicles. Still to be determined is the degree of effect of AirTabs on the foot of the driver.

But hey, if the placebo effect can improve your fuel efficiency by 5-10%, isn't that a good thing? LOL.

Maybe that should be my next mod: I'll install placebos all over the Prerunner! It has to work. After all, the miraculous effects of placebos have been thoroughly proven in more scientific studies than any other product in history. If someone can get me a pack of convincing literature and a few diagrams and photos, I'll make a DIY version.
  Reply With Quote
Old 12-12-2008, 07:51 PM   #10 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,556

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.8 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)
Thanks: 3,324
Thanked 6,124 Times in 3,177 Posts
Pics added to the first post.

EXCELLENT points, akashic.

__________________
Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now in progress...
Ecodriving test:
Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tested: vortex generators (AirTabs) on a Toyota Corolla MetroMPG Aerodynamics 74 01-05-2011 08:13 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com