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I'm in the market for a new car, and fuel efficiency is important since I'm commuting 2 hours a day.

The EPA and Canadian governments use different measures of fuel efficiency. I don't mean just the US/Imperial gallon thing. If I convert those, I get consistently lower mpg listings from the EPA.

But we last bought a car in the US, which we have here now. So I'm unable to figure out what mpg we'll get from a car bought here given the EPA-listed mpg for our car, the real mpg for our car and the Canadian-listed L/100km for the new one.

So my real question is, have Canadian drivers managed to reach the government-listed efficiencies?

Almo
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Canadian fuel economy tests are rather optimistic, especially the highway numbers which only use relatively low speeds. The highest speed in the highway test is 97kph, but the speed limit on twin lane roads is 110kph. The latter speed requires about 1.45x as much power (power to overcome air resistance is proportional to the cube of velocity) to maintain.

It is certainly possible to attain the fuel efficiency by driving like they do in the test, though this is not necessarily advisable.

Compro01
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  • Something seems off in the figure that 110kph requires 1.45x as much power as 97kph. Perhaps it should be "requires 1.45x as much power to overcome air resistance"? – Adam Brown Nov 16 '22 at 01:48
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It is possible to reach those figures, but you'll have to drive like an old lady and also stay mostly in top gear. You'll also need to coast your car as often as possible which is simply engaging the clutch when you go downhill.

It's not practical, but those figures are attainable if you don't mind irritating everyone behind you in the process.

Captain Kenpachi
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    Coasting in gear is more efficient, because modern FI vehicles turn off fuel delivery on overrun condition (RPM are higher than idle with no throttle applied), whereas while coasting in neutral the vehicle consumes fuel as the engine is idling (and idling has other negative implications for fuel efficiency and maintenance long term). Search this site, there were several discussions about it. – theUg Jul 05 '13 at 16:02
  • Good point. will keep in mind. – Captain Kenpachi Jul 06 '13 at 15:47
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Not to directly discuss Canadian situation, but to obtain more or less reliable numbers for real-world fuel-economy (more reliable the bigger the dataset for more popular models) one could use fuel consumption tracking site, such as Fuelly.com. I am using that one because of the usable interface compared to couple others I had seen. It allows you to browse vehicles (cars and motorcycles as well) by brand and model, and further refine your search by the particular engine (so you don’t mix results of, say, vehicles with 4- vs. 6-cylinder petrol motors vs. Diesel or hybrid options) and year.

Unfortunately, as of this writing, it lacks advanced data compilation features which would allow you to filter out specific generation of multi-generation models (Civic, Corolla etc.) or range of years associated with that generation, separate markets (NA and European Ford Escorts are very different, for instance), or combine model names and body styles that would be essentially the same car (Golf/Jetta/Bora/Vento for instance), given the same or similar version of the powerplant. But even the basic functions are enough to get a decent picture of real-world consumption.

theUg
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