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Old 01-08-2008, 07:57 PM   This thread is in the EcoModder Project Library | #1 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,521

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: 52.48 mpg (US)
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Autospeed article: adding a chin undertray to a 1st gen Prius

(Note: see also Adding front & rear undertray to 2nd gen. Prius )

From the Australian web magazine Autospeed -

Some of you may have seen these already...
Modifying Under-Car Airflow, Part 1

Modifying Under-Car Airflow, Part 2
Originally these articles used to be pay-access only, but they've opened them up for public access now.

The project documents the creation of a prototype front partial undertray for a 1st gen Prius, testing, and then fabrication of a permanent version.

Before:



Mockup:



Final version:



The writer reports a 10+% improvement in fuel economy at freeway speeds (100km/h) with the mod in place. I frankly find that a bit difficult to believe, though I don't doubt there was some improvement.

If you read the article you can find a few holes in his testing approach - even though he's fairly aware of things like experimenter bias, and aiming to perform tests on the same day (for consistent weather conditions).

The articles also give a good background on the subject of under car aerodynamics. Definitely worth a read if you haven't seen them yet:
Modifying Under-Car Airflow, Part 1

Modifying Under-Car Airflow, Part 2

__________________
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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