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Old 01-08-2010, 11:12 AM   #76 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,527

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

MPGiata - '90 Mazda Miata
90 day: 54.46 mpg (US)

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

Appliance car Mirage - '14 Mitsubishi Mirage ES (base)
90 day: 62.14 mpg (US)
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Someone PM'd me wondering if this type of spoiler is effectively a "deck lid extension":



Answer: no. It's a roof extension. (Obviously you know that.) Some might call it a mini, mini Kamm back.

Like a deck lid extension, most would agree it's beneficial for reducing drag, vs. not having one, but for different reasons.

A deck lid extension helps by giving detached flow off the rear of the roof/rear window the opportunity to reattach; also a deck lid extension may promote cleaner flow separation from the rear deck.

A roof line extension - provided it continues plan & profile taper - reduces drag by reducing the size (cross sectional area) of the trailing wake where it separates from the back of the car. It may also reduce drag by reducing rear lift (vs. not having one), depending on the shape of the underlying glass/bodywork.
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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
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