Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

MetroMPG · 06-22-2009, 12:03 AM

Just a note on the transition at the base of the new air dam to the undertray...

Note the radius on the bottom of the OEM version. The 90 degree angle on your version will cause flow to separate. Your partial undertray will be seeing turbulence, and likely a locked vortex up front. That'll add drag!

The transition radius doesn't have to be large to retain attached flow - even about an inch is enough.

06-22-2009, 12:03 AM	#75 (permalink)
MetroMPG Batman Junior Join Date: Nov 2007 Location: 1000 Islands, Ontario, Canada Posts: 22,534 Blackfly - '98 Geo Metro Team Metro Last 3: 70.09 mpg (US) MPGiata - '90 Mazda Miata 90 day: 54.46 mpg (US) Appliance car Mirage - '14 Mitsubishi Mirage ES (base) 90 day: 57.73 mpg (US) Thanks: 4,082 Thanked 6,979 Times in 3,614 Posts	Just a note on the transition at the base of the new air dam to the undertray... Note the radius on the bottom of the OEM version. The 90 degree angle on your version will cause flow to separate. Your partial undertray will be seeing turbulence, and likely a locked vortex up front. That'll add drag! The transition radius doesn't have to be large to retain attached flow - even about an inch is enough. __________________ 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