0 Comment

Putting Fuelshark's toothy claims to the test

Device claims to cut fuel consumption by up to 10 per cent

  • Fuelshark

Seeking a last-minute gift for a car-owner?

How about the Fuelshark, a gizmo that claims to cut fuel consumption, by up to 10 per cent or more! For a mere $39.95 (US), a gift like that would top my wish list. If it works.

If it works. That’s always the rub with such gadgets that claim, through various means, often seeming to rely on Earth’s magnetic field, sunspots or fairy dust, to make internal combustion more efficient.

Most, unfortunately, are far better at separating motorists from their cash than saving gas.

The Fuelshark seems more plausible, though, so I did my best to determine whether it’s the real thing.


First, I’ll explain how it works and why the test was a challenge.

It looks like an oversized blue Christmas light, adorned with a white Fuelshark logo and with a business end that plugs into any car’s cigarette lighter ‘ er, “energy socket.”

The printed material accompanying the device is rather obscure: The electrical components in your car’s electrical system are interconnected with each other, it states. To get superior performance,  it must have a clean electrical circuit environment. Many cars develop electrical imbalances over time due to the power demands made by various accessories and normal wear on batteries, spark plugs and other parts.

Got it?

No? Then, perhaps this will help: To maintain optimum performance and improve MPG (this gadget is American), you car will run better with a stable voltage environment. The Fuelshark provides just that.

Still a bit muddled? I was. So I called Fuelshark president Clay Renshaw in California.

Renshaw explained the device contains a high-quality capacitor, a component that takes in and releases electrical energy very quickly.

It lets the Fuelshark pull electricity from the cigarette socket, and then unleash it when it detects extra demand, most likely from lights, power windows, heater, air conditioning or other accessories.

By ?delivering the power when it’s needed most, it takes a load off the engine, and thus saves fuel, Renshaw says.

When you put demand on the electrical system with the Fuelshark in, it’s told, now it’s time to get to work.

For that reason, he says, the device has more impact in city driving than on the highway, where the car is running optimally, and not putting much demand on the Fuelshark.It’s fine for gasoline or diesel engines, but not to be employed in conventional or plug-in hybrids.

Renshaw says the company has sold about 10,000 in a slow start-up since the device was trademarked in 2009. It’s issued only 86 refunds, half for returns in unopened packages, he adds.

Unless you’re a smoker, using it is a breeze: Just plug it into the cigarette lighter. A bright blue glow shows it’s working to, take a bite out of your gas bill and save the Earth.

Fuelshark’s claim to cut fuel consumption, up to 10 per cent or more, can’t be disproved. After all, even zero falls in that category.

In any case, fuel-economy testing is complex. To be meaningful, it must compare a car’s performance with and without whatever device is being assessed, under similar, preferably identical, conditions.

The simplest method is to use a dynamometer, like a treadmill for cars, that simulates a precisely designed and controlled driving route.

But that’s not useful for the Fuelshark, Renshaw says.

‘We’ve never run a dynamometer test, you’re not as able to simulate real-world conditions, the demanding situations in which, he says, the device shines.

He does, however, cite testimonials. One comes from an employee of an electronics factory in China, where the capacitors are made, who used a computer system to analyze the fuel consumption on his daily commute and reported a 12 per cent improvement.

Fuelshark’s website includes several ABC television, news reports about the device, showing endorsements from a couple of consumers and different local reporters, in various U.S. cities reciting identical scripts about how the thing works.

My skepticism meter hit “alert”when I saw those items, but on I went.

The trouble with real-world tests is that it’s impossible to exactly duplicate driving conditions from one trip to the next. Even covering an identical route, you might encounter more or less wind or traffic, or drive a bit more or less aggressively.


Fuelshark recommends measuring results by filling up your tank, driving a while without the device, then refilling, driving with it installed, and then refilling a final time. Simple calculations of kilometres driven and litres purchased will reveal any differences.

Many new cars also display current and average fuel consumption.

I used both methods, and added a third: Analysis through a data logger provided by MyCarma, a division of Waterloo-based CrossChasm Technologies.

I tested my own 2003 Dodge Caravan, a neighbour?s 2005 Kia Spectra, a niece?s 2007 Toyota Corolla and a 2014 Mazda3 from the company’s press fleet.

The assessment involved many hours behind the wheel, doing my best to match urban, suburban and highway drives with and without the Fuelshark.

Based on its dashboard display, the Mazda (which is equipped with its own capacitor) got worse fuel economy with the Fuelshark. Using the data logger, it and the Kia both also did worse with the device plugged in. But the differences ? 1.3 and 2.8 per cent ? were small and certainly within the margin of error created by the slight but unavoidable differences in each trip.

I?d declare ?no effect? from the Fuelshark on them.

The data logger gave the Caravan, over many days of combined urban and highway driving, 7.3-per-cent better mileage with the Fuelshark. The Corolla, driven one afternoon on suburban roads around Oakville, was 8.2-per-cent worse.

But the Fuelshark performed only modestly better when I took the Caravan on very comparable trips, with each segment 20 to 25 minutes long. The device scored 3.5-per-cent better fuel economy on busy downtown streets and 2.2 per cent travelling a little above the speed limit on the Don Valley Parkway.

To add to the confusion, using the fill-up-and-measure technique recommended by Fuelshark, I calculated 14.4 L/100 km for the Caravan over several days with the device in; well above scores of about 11 without it.


In a nutshell, I share the conclusion reached by MyCarma CEO Matt Stevens: The Fuelshark doesn’t appear to have a benefit that exceeds the measurement noise for the tests that were conducted.

Which means, sadly, I can’t vouch for any fuel savings.

Should it go into anyone’s stocking? Well, it’s not much money, and that nice blue light would enhance any car?s ambience.

Follow on
Instagram #wheelsca

Show Comments