On the UK website, fuel efficiency on the base model with the 1.0 liter/999 cc engine is reported at 65.7 mpg, or approximately 30 mpg more than the 36 mpg EPA estimated mileage here in the US. Here is my attempt to resolve the differece:
1. The UK fuel efficiency is reported in Imperial gallons. When converted to US gallons, mpg = 54.7.
2. The Canadian version of the fortwo reports 43.5 mpg (US) with a car that is identical to the US version. So, should we use the Canadian or EPA estimate? In 2008, EPA revised its fuel economy formula & the result was more conservative (lower) estimates. On the EPA website, fuel economy estimates can be converted from current to pre-2008 equivalents. After the conversion, the smart fortwo estimate is 39/46, identical to the Canadian 43.5 mpg combined. It is the revised EPA estimate that is different from what other countries are using, so I say that we using the Canadian number for comparison purposes.
3. So, now we have a difference of 43.5 vs 54.7. How to explain that? The most obvious explanation is that mhd is standard on the Euro fortwo. Estimates are that mhd improves fuel economy by 8% - 11%. So, without mhd, the Euro fortwo is getting about 49.7 mpg.
4. There is a remaining difference of about 6 mpg. I would look first to the fact that the US fortwo is almost 10% heavier than its Euro counterpart. I don't know the exact impact on fuel economy of the increased weight, but it has to result in some reduction, making the comparative numbers very close in the final analysis.
the australian std claims our cars do 57.65 mpg combined (uk gallon) or 48mpg (us gallon) or 4.9L/100km
that is what the government rating is for a turbo fortwo... in reality the combined real world mpg you get is approx 28mpg (us) 50:50 min city/highway driving
the tests are done in a lab and not representitive of real world conditions.... the us testing seems more accurate than the euro lies they feed you
European testing is different. I'm unfamiliar with how they do it, but have read that it's closer to real-world driving.
Example: VW's 2.0 TDI CR140, the engine used in the cars we get, is identical to the engine used in German spec. cars.
USA ratings: city/combined/highway = 30/34/41 mpg
German ratings: city/combined/hwy = 37/48/59 mpg (US gallons)
I have 2 friends with new TDIs, both are getting 36-39 in city/suburban driving, and high 40s on the highway. One (who drives close to the speed limit) says he's seen 51-52 on the highway. Both say the cars are supposed to do significantly better after 10k miles, when they break in a bit.
Add to the mix of testing differences is the fuel used. I would guess that the US EPA tests with the mandated E10 ethanol fuel (there is presently no mandate in the EU for bio-gasoline, and Canada will only go to 5%).
If straight gasoline has a "power factor" of 1.00, E10 will have a "p/f" of 0.94, and E85 0.50**. Straight gasoline has a potential of 45.4 giga-joules of power per metric ton, while straight ethanol only has 26.7, a 59% reduction.
**Some of E85's loss of power can be made up by its ability to be run at higher compression ratios.
But what about running aviation fuel or pure nitrous?? The motor probably would melt down but you'd get great milage I bet..
assuming you drive 20,000 miles a year, the 6% would cost you about $100.... or .27 a day. Probably not worth the extra expense of shipping a Euro version here and paying the import fees. If you are that concerned about milage, walk.
It isn't "the Euro (car) version" that may account for 6%, it is the Euro gasoline that their cars may be tested with that may be an added factor. AVGAS and nitro don't have anything to do with national test results.
The strangulations of different emissions systems and sound levels may also be separate factors. And another factor is that the normally-aspirated Euro smarts run 11.5:1 compression ratio and we run 10.0:1.
... 2. The Canadian version of the fortwo reports 43.5 mpg (US) with a car that is identical to the US version. So, should we use the Canadian or EPA estimate? ...
I think there is a problem with the printed Canadian brochure. It looks like the copy writers in Germany had U.S. figures, assumed them to be Imperial gallons, and converted those to liters per 100 km. If you divide the Canadian numbers in the brochure by 1.2 they are the same as the U.S. EPA's MPG.
Don't forget, the emission system over here is more stringent so it makes the car get less also. I have talked to ppl that took off all their emissions on a car for strictly racing. Drove it around like normal, then on emission day. They put the stuff back on. They got more MPG by having it off and funny thing, it was actually cleaner emissions with it off.
Don't forget, the emission system over here is more stringent so ...
You sure about that? I think the inverse is true. I'd be interested to know for sure. If anyone knows, please post some real data. I'l also do a bit of research and post what I find.
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