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

spacer spacer
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.
spacer spacer


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

spacer spacer

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...
spacer spacer

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.

Show more posts:   page 1 - page 2 - page 3 - page 4 - page 5 - page 6 - page 7

Posted Tuesday, October 3/06 in General

aero Model T under construction Harry Stevinson was decades ahead of his time. In 1933 at the tender age of 17, he put his self-taught mechanical & design talents to work fabricating a streamlined one-off car that was both faster and more efficient than the Model T Ford it was based on.

I learned about Harry and his car from his son, Tom, who lives near the same town I live in. Tom and I sail together in the local sailboat races, and the topic of his dad's Model T came up one day in the marina parking lot when he commented on some modification I had made to the Blackfly.

What emerged was a fascinating story along similar lines as the aero-modified Metro XFi - only this story took place 60 years earlier...

Continued inside...

Posted Saturday, September 9/06 in Mods & Tests

literal boat tail One of the biggest aerodynamic problems with the majority of hatchback-shaped vehicles (like my Blackfly) is the size of the trailing wake. The large reduced pressure zone acting on the rear end can account for up to 1/3 of total drag.

That said, a hatchback configuration isn't automatically an aerodynamic death sentence. On the contrary, three of the most slippery production cars available in recent years were hatchbacks: the 2nd generation 2004- Toyota Prius (Cd .26), 1999-06 Honda Insight (Cd .25), and 1999-05 Audi A2 (Cd .25).

But these cars are exceptions to the rule. So what do you do if you're stuck with a conventional more or less van-shaped hatch? Just grin and bear the aerodynamic shame of it? No way! Get out the cardboard and duct tape, and go to work fixing what the stylists messed up!

Continued inside...

Posted Thursday, August 31/06 in Mods & Tests

Mirror drag CFD simulation Mirror, mirror on the door -
Is your airflow good or poor?

Sorry. I won't do that again. But that is indeed the topic of this installment of what sadly appears to be becoming a once-monthly update at MetroMPG. (I will try harder in September - it's not for lack of subject matter, believe me.)

My desire to find concrete information about the effect of side mirrors and fuel economy was piqued from seeing the number of high-efficiency concept cars that substitute video cameras for side mirrors. Why? Is it just for the techno bling factor? Or are there real gains to be made by rethinking side & rear vision?

Continued inside...

Posted Wednesday, August 2/06 in Mods & Tests

Speed vs MPG The fact that you're reading articles on a fuel economy web site says you're probably already aware that speed kills ... mpg. Resisting the urge to drive fast is one of the easiest and most effective methods for seeing big savings.

We've all seen stats from NRCan and the EPA about how much more fuel is burned as speed rises: Driving at 120 km/h instead of 100 uses about 20% more fuel (NRCan); observing highway speed limits can save 7-23% (EPA).

Those are serious numbers. But reading a stat is one thing, and seeing it laid out graphically is a real eye-opener. So I set out to collect some hard evidence for the Blackfly: a graph of speed vs. fuel consumption.

Continued inside...

Posted Friday, July 14/06 in Suzukiclone info

1989 Metro XFi Aero Car Apologies to my reader (to borrow a joke from Click and Clack) for the long delay since my last post. I spent most of June on a trip, travelling about 1400 kilometers on a 100 ton diesel hybrid. But I'm back now, catching up on a variety of tasks, and have a serious backlog of interesting things to talk about.

Let's start with this radically modified-for-fuel-economy 1989 Geo Metro XFi.

Apparently, owning one of the most fuel-efficient cars ever sold in the U.S. wasn't enough for Doug Heffron. So in 1993, motivated in part by his daily 50 mile commute, he transformed it in his garage into this amazing 2-passenger highway commuter car capable of 75 mpg (US) (3.1 L/100 km; 90 Imperial mpg). That's a whopping 29% higher than its original EPA highway rating.

Continued inside...

Posted Wednesday, May 31/06 in Driving efficiently

Coasting for better fuel economy. As I mentioned in my previous record tank entry, I used to do a fair amount of engine-off coasting in my Honda Accord. The main reason I abandoned the technique in the Firefly was because it messed up the ScanGauge, which would go to sleep when I killed the ignition (and skew its fuel economy information while it missed counting distance travelled).

As soon as I learned that a kill switch that bypassed the key kept the ScanGauge active with the engine off, I immediately set out to run a test to find out what I'd been missing.

Turns out, I'd been missing a lot.

Continued inside...

Posted Tuesday, April 25/06 in Driving efficiently

Auto stop: the old fashioned method Two records were broken lately: oil hit $75 US a barrel, and I squeezed 60.7 mpg (US) from my last tank of gas - a personal best.

(For those of you more fluent in other units, that's 72.9 imperial mpg, or 3.9 L/100 km.)

You'd be forgiven for thinking that the return to high gas prices and my recent fuel economy performance are related - but they're just a happy coincidence. In fact, for most of this tank - actually, before the latest spike in gas prices - I had been test driving a new driving technique. Well, really it's an old technique that I had stopped using and have now returned to with open arms... and great results.

Continued inside...

Posted Wednesday, April 5/06 in General

Blackfly odometer last fall The further you sink into MPG nerdity, the sooner it will become clear that you need to know how accurate your odometer is. Why is it important? I'm glad you asked!

It's important simply because an inaccurate odometer will throw off your mileage calculations. Maybe your fuel economy is actually worse than your odometer has led you to believe... or maybe it's better! Maybe you switched to different wheels or tires (with a slightly different circumference). Or maybe all this time your odometer has been out of whack straight from the factory, and you just didn't know it.

A 2% error on a 50 MPG vehicle = 1 MPG off. And a 2% error (or worse) isn't uncommon. The fact is, you'll never know if you don't check it out.

Continued inside...

Posted Monday, March 27/06 in General

Tach update Revolutionary feedback ...

Since posting my RPM vs. MPG experiment, I've heard back from a couple of people. Some good points were raised, so I've added their comments to the end of that page.

Jump to Showdown: testing RPM vs. MPG at a fixed speed and scroll to the bottom of the page for the new stuff.

More miscellany after the jump...

Continued inside...

Posted Monday, March 13/06 in Mods & Tests

Firefly torture test: 5100 RPM in 2nd gear! If you row your own gears (as most fuel economy nerds do), here's a mini-experiment that should be of interest.

I recently did a test run that nicely illustrates the fuel efficiency "costs" of reciprocating mass, accessory drag, and internal engine & transaxle friction at varying engine RPM.

If you ever doubted the economy driving tip that says you should be in the highest practical gear at the lowest possible cruising speed, doubt no more.

Continued inside...

Show more posts:   page 1 - page 2 - page 3 - page 4 - page 5 - page 6 - page 7

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