My Pontiac Firefly / Chevrolet Metro / Geo Metro / Suzuki Swift welcomes fuel efficiency nerds everywhere

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Latest fuel economy stats
for my '98 Firefly 1.0L 5-speed
  best: 2.3 125.1 104.2
 worst: 6.4  44.1  36.8
prev.3: 3.3  82.3  68.6
   all: 3.8  73.4  61.1
L/100km | mpg IMP | mpg US
Jul 28/07: more, graph, calc.
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Best non-hybrid MPG: Mitsubishi Mirage
Highest MPG for a new car: Mitsubishi Mirage?
Mitsubishi's 1.2L, 3-cylinder Mirage is the first new non-hybrid car that can match an old Metro's mileage. The company says 44 mpg (US) highway, 37 city. (Some drivers are already beating that in various economy driving contests.) How? An efficient engine, very light weight and aerodynamic design.

Cheapest to own? 2015 Nissan Micra Forum
2015 Nissan Micra Forum
The Micra's fuel economy isn't its most notable feature -- the $10,000 price is. That makes it one of the cheapest cars to own. And its 109hp, 1.6L engine and good power-to-weight ratio means it's fun to drive too.

Latest 10 posts:
1. Recipe for getting 99.7 mpg from a Geo Metro
2. - famous aerodynamic Honda Civic gets a web site
3. Snapshot: effect of tire pressure on rolling resistance
4. 65+ vehicle modifications for better MPG
5. Metro mania: forget stocks, put your money in old Geos!
6. 100+ Hypermiling / ecodriving tips for better gas mileage
7. Experiment: how long should a block heater be plugged in?
8. Everything old is new again: Car and Driver magazine modifies an econobox to improve MPG
9. Project Convertible XFi: alfresco efficiency
10. The floor is yours: MetroMPG opens a fuel efficiency forum
11 ... 64. Show all posts

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Good MPG forums: I spend a lot of time at and have also been known to lurk around

Chevrolet Aveo forum - discussion of the Chevrolet Aveo and its siblings (Pontiac Wave, Pontiac G3, Suzuki Swift+, Daewoo Kalos).

> Lots more Metro links...
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Send me a note:
darin AT metrompg D-O-T com,
or here

MetroMPG has opened a fuel economy forum
Read about the project here, or go straight to
ScanGauge fuel economy computer Save fuel with a ScanGauge II fuel economy computer.
I personally recommend this tool. I've owned both versions (I and II) and can't say enough good things about it. If you're serious about saving fuel, get one.

For more information and to order, visit EcoModder.

MPG gadgets: Separating the wheat from the chaff

Posted Friday, December 30/05 in Mods & Tests

separating the wheat from the chaff - literally!

Two links of particular interest:

  • Tony's Guide to Fuel saving - a professional engineer's view
  • I was happy to come across this week. It's a level-headed shelter from the virtual storm of over-hyped additives, modifications and gadgets out there.

    The site is run by a British automotive engineer who examines fuel saving claims from a very rational - not to mention educated & qualified - point of view. He debunks well-known modifications and additives apparently out of sheer irritation with the pseudoscience surrounding them. (In fact, calling some of their claims "pseudoscience" does the word a disservice.)

    You know you're dealing with a level-headed guy when he openly invites critics to contact him in the case that, "either I have made a genuine error (in which case I need to fix it) or perhaps I need to explain something better." Kudos for that.

    He also points out the folly of uncontrolled on-road testing or ScanGauge-derived data as "proof" of the in/effectiveness of modifications. Variability is simply too great to provide meaningful results when little or no effort is made to control for things like experimenter bias, speed, wind, grade, rates of acceleration, ambient temperature & humidity, whether the vehicle is consistently warmed, etc.

    My own fuel economy testing methods are undoubtedly faulty by industrial standards - though I have attempted to only present data collected from bi-directional, back-to-back, cruise-controlled (constant speed) runs on the same long stretch of level road in calm conditions with a fully warmed vehicle, and in the absence of other traffic. I'll freely admit it's still no chassis dynamometer, but it's as close as I can reasonably get without one. isn't all-encompassing (nor would I expect a volunteer-built site to be), but what is covered is covered thoroughly: from fuel line magnets, to oil and/or fuel additives (e.g. acetone), to induction turbulence inducers (e.g. Turbonator), and more. There are a few other miracle cures that I would like to see covered: hydrogen generators and water injection come to mind. [Edit - Jan 6/06: hydrogen generators and water injection are in fact mentioned at My oversight.]

    My only criticism of the site is one of functionality: it needs better navigation. E.G. a menu on each page, or a breadcrumb trail, or a site map, or a prominent search box (there's one part-way down one page), or some combination of these. There's a wealth of information to be found, and it's a shame it's not as easily accessible as it could be.

    [Edit - Jan 16/06: Since writing this, has been updated with much improved site navigation and a search box on every page. It's much easier to find your way around now.]

    Popular Mechanics

    And of course I would love to read comments about (or see industrial test standards applied to) aerodynamic modifications, for example. Then again, there is a distinct lack of commercially available aero modifications to test or comment upon.

  • Looking for a Miracle - Popular Mechanics
  • Can copper tubing, cheap magnets and wacky gimmicks really boost your mileage by as much as 300 percent? PM's Mike Allen puts the latest MPG gadgets to the test. Please step back from the truck.

    Another timely debunking of several specific fuel-saving gadgets - an entertaining and edifying read.


    Both of these are sites worth visiting for anyone interested in increasing efficiency (or power, for that matter) and who have ever spent money on something they hoped would achieve either. The moral from both revolves around a simple concept we learned about in grade five: the scientific method.

    The only way to know for certain if something works is through a well-designed experiment. On-road, short-term, tank-to-tank testing doesn't really cut it. Seat-of-the-pants observations don't cut it. And as infectious as they may be, excited customer testimonials certainly don't cut it.

    Sites like these have helped me to understand the likelihood that I threw away money on $35 platinum spark plugs, hoping they would improve mpg over my nearly-new stock plugs. And we already know what I found out about my $85 air filter.

    EcoModder fuel economy forum Note: MetroMPG has opened a fuel economy forum
    Read about the project here, or go straight to

    darin AT metrompg D-O-T com, or here