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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-17-2008, 10:26 PM   #1 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,513

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

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 60.16 mpg (US)
Thanks: 4,058
Thanked 6,957 Times in 3,602 Posts
SAAB 9-X BioHybrid active rear aero - 10% improvement

Of course you ask: 10% improvement in what?

The Advanced Design Director (Europe) simply says: "...improves aerodynamic efficiency by up to 10%." So I'm assuming he's referring to Cd.

The roof extension slides back by nearly 10cm at highway speeds (and also tilts up under hard braking). There's also an active spoiler/diffuser under the bumper:




What's interesting is that there appears to be gaps between the extensions and the surface they extend from, creating slots. Presumably airflow would be drawn through the slots, top and bottom, by the lower pressure behind the car.

__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
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
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-17-2008, 10:36 PM   #2 (permalink)
Banned
 
Join Date: Feb 2008
Location: california
Posts: 1,329
Thanks: 24
Thanked 161 Times in 107 Posts
Toyota has been putting these on its hatchbacks, SUVs and minivans for years. It doesn't have to be active. It just has to work in the wind tunnel. The gap splits the air cascading off the roof onto the back of the vehicle in order to spread out the pressure gradient and reduce turbulence.







And people thought they were just for looks.
  Reply With Quote
Old 03-17-2008, 10:48 PM   #3 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,513

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

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 60.16 mpg (US)
Thanks: 4,058
Thanked 6,957 Times in 3,602 Posts
I think the second image looks more like one of those "keep the rear window clear" devices, rather than a drag reduction device.

Anything that sticks up higher than the trailing edge of the roof would be dubious as a drag reducer.
__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
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 03-18-2008, 12:33 AM   #4 (permalink)
Banned
 
Join Date: Feb 2008
Location: california
Posts: 1,329
Thanks: 24
Thanked 161 Times in 107 Posts
Yeah the second one is a 4runner which doesn't have a rear window wiper. The rest do.
  Reply With Quote
Old 03-18-2008, 08:09 AM   #5 (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 86 Times in 57 Posts
Quote:
Originally Posted by MetroMPG View Post
I think the second image looks more like one of those "keep the rear window clear" devices, rather than a drag reduction device.

Anything that sticks up higher than the trailing edge of the roof would be dubious as a drag reducer.
This is what I think too.

I really like what they did with the saab. They're taking it to the next level.
__________________



www.HyperKilometreur.com - Quand chaque goutte compte...
  Reply With Quote
Old 03-18-2008, 03:49 PM   #6 (permalink)
Master EcoModder
 
Join Date: Mar 2008
Location: USA
Posts: 568
Thanks: 1
Thanked 73 Times in 58 Posts
Crude interpretation of Fowler flap?

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Video: active aero (grille block) via shape memory alloy MetroMPG Aerodynamics 7 01-30-2010 11:21 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com