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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 12-26-2009, 11:10 AM   #11 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,580

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)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 66.29 mpg (US)
Thanks: 3,363
Thanked 6,155 Times in 3,189 Posts
Quote:
Originally Posted by mcrews View Post
so after smoothing the under belly all the way back, would a 3'' dam negate that work?
Can't answer that definitively. But look at super-efficient vehicle designs. They all have smooth undertrays. How many also have air dams?

Quote:
What angle are you measuring?


The angle between the red lines is your approach angle.

__________________
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
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 12-26-2009, 07:18 PM   #12 (permalink)
wdb
lurker's apprentice
 
Join Date: May 2008
Location: the Perimeter
Posts: 854

PlainJane - '12 Toyota Tacoma Base 4WD Access Cab
90 day: 20.98 mpg (US)
Thanks: 419
Thanked 194 Times in 148 Posts
Air dam + undertray should be more efficient than either alone. Air dam + splitter + undertray should be more efficient still. Susceptibility to damage is probably the biggest reason you don't see more front splitters on road cars.
  Reply With Quote
Old 12-26-2009, 07:55 PM   #13 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,580

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)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 66.29 mpg (US)
Thanks: 3,363
Thanked 6,155 Times in 3,189 Posts
Quote:
Air dam + undertray should be more efficient than either alone. Air dam + splitter + undertray should be more efficient still.
wdb: could you elaborate or post links to supporting info?
__________________
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 12-27-2009, 08:53 PM   #14 (permalink)
Master EcoModder
 
Join Date: Dec 2008
Location: South Jersey
Posts: 553

Little Blue - '98 Ford Escort ZX2 Cool
Team ZX2
90 day: 44.75 mpg (US)

Big Red - '00 Ford Excursion XLT
90 day: 15.53 mpg (US)
Thanks: 5
Thanked 45 Times in 29 Posts
Quote:
Originally Posted by mcrews View Post
so after smoothing the under belly all the way back, would a 3'' dam negate that work?
the bottom of my front lip is 7 3/4 inches to the ground. I could ratchet my springs down maybe one inch. But I had lowering springs for about 1 yr and I was ALWAYS scrapping my front lip.
What angle are you measuring?

As Metro said, no one can tell you exactly how your car will respond. The cheapest method of finding out is to just tape some cardboard on there and do some coast down tests. Underbelly pans take quite a bit of time and labor to get on, Air Dams are quick and easy. Quick and easy is the route I chose and it worked. May not be optimal, but it has been saving me money since the day I bolted it on. It was the best $13 I've spent so far...
__________________
  Reply With Quote
Old 12-28-2009, 09:00 PM   #15 (permalink)
Left Lane Ecodriver
 
RobertSmalls's Avatar
 
Join Date: Aug 2008
Location: Buffalo, NY, USA
Posts: 2,258

Prius C - '12 Toyota Prius C
Thanks: 79
Thanked 283 Times in 196 Posts
Quote:
Originally Posted by wdb View Post
Air dam + undertray should be more efficient than either alone. Air dam + splitter + undertray should be more efficient still.
Well, not necessarily. An air dam increases the frontal area of the car, and it has to make up for the increased A with reduced Cd. If the underside of the car is ugly, it's easy to imagine that happening. If it's smooth... well, I'm not sure, but I'm inclined to believe it's best to let air under the car.

I believe this must be settled in a wind tunnel, wind tunnel simulation, or real-world coastdown testing.
  Reply With Quote
Old 12-31-2009, 01:26 PM   #16 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,288
Thanks: 18,180
Thanked 5,999 Times in 3,653 Posts
good spot

Quote:
Originally Posted by Old Tele man View Post
...that's what I recall too. Sorta like Goldy-locks and a "...not too much; and not too little" situation..." where either side of "...just right..." isn't gonna help you.

...just wanted to make the point that "sometimes" the "good spot" (vehicle rake angle) isn't something you want to arbitrarily be playing with, unless you know what you're getting yourself in for.
EcoModder really needs a big wind tunnel so we can make these kinds of refinements.
I asked Santa,and I really tried to be a good boy,but to my knowledge,nothing came of it.
Unless Darin is holding out on us................................................ ............
  Reply With Quote
Old 12-31-2009, 02:00 PM   #17 (permalink)
Master EcoModder
 
mcrews's Avatar
 
Join Date: Oct 2009
Location: Texas
Posts: 3,523

The Q Sold - '02 Infiniti Q45 Sport
90 day: 23.08 mpg (US)

blackie - '14 nissan altima sv
Thanks: 2,203
Thanked 659 Times in 474 Posts
Quote:
Originally Posted by aerohead View Post
EcoModder really needs a big wind tunnel so we can make these kinds of refinements.
I asked Santa,and I really tried to be a good boy,but to my knowledge,nothing came of it.
Unless Darin is holding out on us................................................ ............
A little off topic, but maybe not so much........

Specificly.....what does "REALLY TRIED" look like?????
  Reply With Quote
Old 12-31-2009, 02:20 PM   #18 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,288
Thanks: 18,180
Thanked 5,999 Times in 3,653 Posts
look

Quote:
Originally Posted by mcrews View Post
A little off topic, but maybe not so much........

Specificly.....what does "REALLY TRIED" look like?????
I don't know if we have an avatar for that.
  Reply With Quote
Old 12-31-2009, 04:40 PM   #19 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,191
Thanks: 179
Thanked 1,521 Times in 1,122 Posts
Quote:
Originally Posted by aerohead View Post
I don't know if we have an avatar for that.
...a picture of your congressman? sounds like something they'd say.

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
CdA list Daox Aerodynamics 170 08-07-2020 04:22 PM
First ride on a (semi-)recumbent bicycle: BikeE - got a CCM Evox 120 MetroMPG Alternative Transportation 20 11-14-2011 08:29 AM
Lower your 92-95 Civic and still ride comfortably! TomO Off-Topic Tech 1 11-05-2009 11:36 AM
Joy Ride or Killjoy? SuperTrooper General Efficiency Discussion 19 08-03-2009 10:49 AM
Bike ride story. Assualt? mhmitszach Alternative Transportation 16 08-20-2008 06:49 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