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.

Interview with Ron DeLong, inventor of the ScanGauge

Posted Wednesday, February 21/07 in General

Many the FE nerd's favourite tool: the SG2

The ScanGauge has become such an indispensable tool for fuel efficiency enthusiasts that some people, when shopping for second-hand vehicles, have stopped considering pre-1996 models to ensure that a ScanGauge can be used.

In other words, it has quickly become the fuel saver's favourite gadget.

With this in mind, I set out to learn more about the history of the ScanGauge and its inventor, Ron DeLong. I recently spoke to Ron on a range of topics: his background, how the ScanGauge came to be, and some future plans for the magic little box.

In the beginning ...

Ron's truck
Ford of Canada gets the dubious honour of having built a problematic dual-fuel F-150 which led Ron DeLong to his ScanGauge 'Eureka!' moment.

It started back in 2001 with a brand new Ford F-150 pickup truck that Ron had bought. It wasn't running right, and its fuel economy wasn't up to snuff. Said Ron, "the 500 cubic inch engine in my 1976 Eldorado convertible was getting better mileage than this truck!"

At the Ford dealership, Ron described his fuel consumption concerns to the technician, who plugged a box into the truck's OBDII port and took him out for a drive.

"The technician was saying: 'these trucks are really sensitive to driving habits,' and he was using instant feedback from this monitor to give me pointers on what to do to increase fuel economy."

"I said: 'Sure, but I don't have my own little box to tell me what I'm doing!'"

The light bulb went on ...

Fortunately, Ron was well positioned to take this "Eureka!" moment and do something productive with it.

In his words, he'd been "doing data" for a long time, having graduated as an electrical engineer from Cal Poly Pomona in 1975, and with years of work in the automotive industry.

Air bags
Honda is currently using another of Ron's developments - the Motorola E-Field integrated circuit - to control airbag deployment in side airbag-equipped vehicles.

(In fact, your vehicle may be equipped with another device that Ron developed while working at Motorola, in collaboration with MIT. If you're driving a Honda with side airbags, those airbags are controlled by an "E-Field" electric field sensing microchip that determines the presence, location and size of the vehicle's occupants to tailor an appropriate airbag response in the event of a collision. Other OEM's are looking at the E-Field chip, and the technology has potential beyond the auto sector.)

Full time retiree ...

Ron retired from Motorola to start Linear-Logic and work full time on the ScanGauge. The business now employs 5 people in Mesa, Arizona, where the programming and assembly is also done.

The first version of the ScanGauge went into production in late 2004. Last June (2006), the ScanGaugeII came out.

Who uses the ScanGauge?

According to Ron, it's been embraced by 3 general groups...

  • Traditional gearheads: Ron explains, "these are the guys who in the old days used to install extra gauges on the dash that gave more info than the idiot lights could." Typically "performance" (speed) oriented folks, these DIY types want to know everything the car is doing when it's being pushed hard.
  • RV owners: these people have a kind of mixed interest. The engines in their (typically heavy, un-aerodynamic) vehicles also tend to get pushed fairly hard, so the drivers want to keep an eye on critical info. At the same time they're also concerned about fuel economy and want to monitor that as well.
  • Fuel economy nuts: these are the MPG obsessed folks (you know who you are) who, prior to the ScanGauge, had to rely on infrequent fill-ups, or relatively crude vacuum gauges for feedback on driving technique or changes made to their vehicles.

Customer feedback ...

ScanGauge before & after
Feedback from customers prompted Linear-Logic to place the original ScanGauge (top) on a strict diet, with good results for the svelte ScanGaugeII (bottom).

After the launch of the original ScanGauge, the most frequent comment received at Linear-Logic was related to aesthetics: customers wanted a sleeker package, and a display that was easier to read. The ScanGaugeII was Linear-Logic's response: 1/4 the size, but with a larger display and user-selectable backlight colour.

Ron says another common request was for the ability to reprogram the unit in the field. While the company still accepts units back to be reprogrammed with the latest version of the software, they're trying to get away from this with a secure interface that will permit customers to download the software and upgrade it themselves by connecting the ScanGaugeII to their home computer.

Trials & tribulations ...

I asked Ron what kinds of challenges he faced while developing the ScanGauge.

"What takes the most time are the vehicle incompatibilities & bugs," he says. He spends a lot of time troubleshooting different vehicles and the way they communicate (or don't communicate) about their various systems through the OBDII port.

  • An example familiar to many fuel economy enthusiasts is the "fuel cut" feature. It's common for fuel-injected engines to stop injecting fuel when the accelerator is released above a certain engine RPM. The problem is that manufacturers don't follow a standard method of describing when this mode is active. The result is that some cars continue to report active fuel injection to the ScanGauge, even when it's not actually happening. (Ron adds that if your car happens to be one which doesn't accurately report its fuel cut state via the ScanGauge, the net effect on fuel consumption calculations is very small, likely 0.1%.)
  • Another example: "We were having some trouble with multi-displacement systems." GM's 'Displacement on Demand' is one such system, but the issue isn't limited to GM's cars: "The problem is that there is no industry standard method to indicate the displacement change via OBDII." In cases like these, Ron says he rents the troublesome vehicles to sort out each one's idiosyncrasies.

He adds that he has discovered some manufacturers are notably worse than others at following industry protocols.

Looking ahead ...

What might we see in future ScanGauge versions/software releases?

  • I was happy to learn from Ron that one future upgrade is the ability to view both Trip (average) and Instant fuel consumption on the same screen (on the "Gauges" screen). This is something I know many fuel economy nuts will appreciate.
  • Another future improvement that ScanGauge aficionados may already be aware is coming is the ability to log data for viewing/analysis on any computer. (The current ScanGaugeII already has the the physical interface that will enable this feature when it's released.)
  • The previously mentioned in-the-field programming feature would also permit users to download upgrades from Linear-Logic that are customized for specific car models. Toyota Prius owners, for example, could download and install on their ScanGauges a custom gauge package and fuel consumption algorithm. This would give them more detailed information than is currently available - for example, about the hybrid battery pack temperature and state of charge.
  • I was surprised to learn that some vehicles offer much more information than is currently available in the standard set of gauges the ScanGauge currently offers. For example, some cars have multiple temperature sensors (e.g. cylinder head, transmission), or a gear indicator (drivers of automatic transmissions would benefit knowing when the torque converter is locked up). Ron says he would like to offer ScanGaugeII users the ability to access this vehicle-specific information through "custom" user-definable gauges.
  • Ron emphasized that the current ScanGaugeII was designed to have a long shelf life: "Its processor is currently less than 1/2 utilized." So, as new software features are developed, users will be able to add them to their existing unit with in-the-field re-programming. He doesn't intend to force people to wait for a "ScanGaugeIII" to get these upgrades.

Old school blues ...

Pre-OBDII victim
Unfortunately, owners of pre-OBDII cars will not be seeing a slick ScanGauge-like instrument from Linear-Logic.

Another question that comes up frequently in fuel economy forums is what kind of fuel economy instrumentation is available for pre-OBDII vehicles. I asked Ron if he had any plans to offer a ScanGauge that would work with older cars.

"We considered it for some of the more popular vehicles, but even within the same model year there are protocol differences that make this complicated," he said.

By the sounds of it, Linear-Logic has its hands full improving a good product for a growing market (OBDII-compliant vehicles), rather than worrying about a relatively small group of folks driving a declining number of older vehicles.

Which raises the final question:

How's business?

"It has been successful mainly through online sales and word-of-mouth," Ron says. "We are only now making a concerted effort to get it into stores and promote it more through advertising."

I can personally attest to the success of the word of mouth process because I've been part of it. I've been directly responsible for several people getting ScanGauges, and have likely indirectly influenced many more through this site and in the forums.

As an unapologetic fan of Linear-Logic's work, I for one am happy that Ron DeLong had trouble with that Ford pickup back in 2001. Future plans for the ScanGauge sound exciting - which is no surprise to me, given the enthusiasm that Ron projects when talking about his work. I wish him and his company continued success and look forward to the future evolution of the ScanGauge.

Resources ...

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