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.

2006 retrospective (there's more where that came from)

Posted Thursday, January 25/07 in General

2006 web site stats

2006 was quite a year for It was the first full year the site was up, and apparently (judging by the visitor stats), you efficiency nuts really like reading about driving techniques, mods and experiments on the Blackfly:

  • With a few exceptions, most of the mods achieved only small MPG improvements, but when you add them up, they totalled a healthy 28% boost in fuel economy

  • "Unconventional" driving techniques yielded the biggest results: 38% better fuel economy, and that's with the mechanical/aero mods excluded from the calculation.

Here's a summary of the mods, driving techniques, and 2006 web stats, plus a preview of what's in store for 2007.

Aero & mechanical mods - Total improvement: 28% ...

aero and mechanical mods

I never actually drove the car with every single mod in place at the same time, but if I had, I would have seen close to a 28% increase in fuel economy compared to stock.

Total = 28% *

(* Now I'll be the first to admit this tally is flawed for a number of reasons (e.g. different weather conditions, speeds at which the tests were run). Take it as an impressive "estimate" rather than an irrefutable truth.)

Driving technique - 38% improvement ...

driving technique

Technique was the dominant factor in last year's record tank of 80.8 mpg (US) / 97 mpg (Imperial) / 2.9 L/100 km over 359 mi. / 578 km.

(But don't make the mistake of directly comparing the gains from technique to improvements from mods, because they're apples and oranges: The mods tally was almost entirely measured at steady highway speeds, whereas the driving technique figure comes from looking at sub/ex/urban driving.)

I arrived at the 38% figure by comparing 6 fill-ups of predominantly sub/urban driving: 3 from the Blackfly and 3 from its predecessor, Firefly #1 which never saw much engine-off coasting, or the pulse & glide technique.

  • Firefly #1, 3-tank tally: 1474 km, 83% city driving ... 5.2 L/100 km / 54.0 mpg (Imp) / 45.0 mpg (US)

  • Blackfly, 3-tank tally: 1724 km, 83% city driving ... 3.3 L/100 km / 86.5 mpg (Imp) / 72.0 mpg (US)

If you do the math, you'll notice the MPG is actually 60% higher for the Blackfly. But when I subtracted the effects of the Blackfly's mods (which weren't on Firefly #1), the figure drops to 38% ** (see calculations at the end of this post).

Web site activity ...

You efficiency nuts ("enthusiasts", perhaps, is a nicer description) apparenly really like following the fuel economy adventures of a guy and his econobox.

The number of visitors to MetroMPG rose steadily through the year (the rate of increase rose too), and thanks to your clicks, I even made a few bucks from Google advertising. (Thanks!)

Annual totals

2006 web stats

Page Loads: 68,872
Unique Visitors: 28,076
First Time Visits: 23,665
Returning Visits: 4,411

Daily averages

Page Loads: 189
Unique Visitors: 77
First Time Visits: 65
Returning Visits: 12

The averages continue to rise month over month. E.G. the average number of page loads & vistors per day at the end of December were 254 and 111.

The single most popular post was Aero mods - 1930's style. Traffic to that page over 2 days was triple the daily average, thanks to a link from

Other web miscellany:

  • $189.46 (US): earnings from Google ads. (Note: I sure don't do this for the money - it works out to about $1.25 an hour, before server expenses!)

  • 85: number of times readers wrote to me through the contact page.

  • 73: readers who are signed up to receive e-mail updates (automatic notification when I post new stuff on the site).

  • 19: number of topics posted in 2006.

  • 19: coincidentally 19 is also the average number of days between new posts.

2007 - what's in store ...

XFi cam
One of 2007's upcoming mods: the Blackfly gets an XFi camshaft.

I'm actually not even finished writing up everything I tried in 2006. So, yes, the first two items on the list are technically leftovers. The remaining items, however, are fresh and tasty mods / experiments on this year's to-do list.

  • Full undertray: the cat's already out of the bag. It delivered only a 2.2% improvement in fuel economy. I'll theorize about it when I post the detailed writeup.

  • Roof racks: out of curiosity, I did a few non-scientific runs - one with empty roof racks, and one with a bike tied to them. The effect on fuel economy was startling. Update: Roof rack article posted March 10, 2007

  • Cam swap: one of the mechanical differences in the Metro XFi which resulted in its much higher EPA rating was a special "efficiency cam". I've got one. And it's going in the Blackfly. Update: XFi camshaft installed, posted April 24, 2007

  • Airtabs/vortex generators: I've read much about these, and have enough to run a test (when test-friendly weather returns).

  • Lowering: like most 1995-2000 Suzukiclones, the Blackfly rides unusually high off the ground for a small car. Lowering it may improve the aerodynamics (and its appearance).

  • Fiberglass Kammback: the Kardboard Kammback will re-appear on a more durable form - which may serve as a mounting point for an extension & further experimenting.

  • More aero: experiment with front wheel skirts, wheel deflectors, wheel boat-tailing

  • Home made, fully electric 1992 Geo Metro: I've actually been working on this project with a friend for almost a year (it's one reason for the decreased frequency of posts at the end of 2006). Project ForkenSwift will be documented in full detail (on its own web site) sometime in 2007.

  • ... and much more.

Thanks ...

To my tens of regular readers: thanks for the hits, the Google ad clicks, and the encouragement/feedback in 2006!

** Calculations used to deduct the effect of mods from the Blackfly for comparing city driving to Firefly #1:

-5.2% transmission advantage
-10.3% alternator advantage
-1.2% aeromods advantage (calculated based on avg. city speed of 25 mph vs testing speeds around 55 mph)
-6.0% rolling resistance (this is a WAG - the Blackfly has LRR tires and higher pressure than the first Firefly)
= -22.7% total deductions (this is actually a liberal estimate, because the Blackfly was not running alternator-less, nor with all aero mods, and the taller tranny was only in place for 2 of the 3 tanks)

= 37.5% estimated difference due to driving technique alone

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