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Autobloggren reader Ron asked us one question: why does it seem that American cars in Europe sip less fuel? As he compared what look like identical models on either side of the Atlantic Ocean and consumption figures seem to differ.

First problem is finding two identical models. Then, pollution regulations are different in the USA compared to the EU. As a general rule, the EPA focus on exhaust air quality while the EU aims about quantity and has longer terms for other pollutants. As a consequence, injection systems might be tuned differently. Some people might think that gasoline is different. Europeans have two different types of gasolines: 95 and 98 RON which are more "premium" than the ones sold in the U. S. but, provided the fact that the injection systems are ready for the gas type, mileage should not affected (remember the "don't use premium if not needed"?). Perhaps the most important factor to consider are the differences between the mileage test procedures. The current EU test cycle is considered to give considerably higher results than the latest 2008 EPA test procedure. Finally, make sure that the numbers you are comparing are in the same units. Numbers from the UK are typically expressed in miles per Imperial gallon. One Imperial gallon is 1.16 US gallons.

Then there's how these figures are calculated. Can we compare EPA's highway cycle to the EU's "highway" cycle? No. EU's highway cycle supposes the car at constant speed. As many Europeans can tell you, that's tough to get and real-world mileage figures actually are closer (and slightly higher) than the "Combined cycle", which is more comparable to EPA's highway cycle. Add the fact that EU's measurings are based on models and the EPA actually tests the cars. To make things even more complicated, the Japanese cycle is even different and focus on lower speeds.

Therefore, and as a rule of thumb, comparing EU and U. S. specifications is something that we can only do at approximate levels. However, we have the right to ask U. S. manufacturers to get us more fuel-efficient cars and their European operations show that they have those models. GM heard this when bringing the Astra and Ford did the same with the Focus and will bring the newer Focus and Fiesta stateside.

Here's some information about U. S. manufacturers we obtained (all conversions obtained here)

Saturn Astra 2009, 1.8-liter, 140hp, 5-spd manual - EPA's figures: 32mpg U. S. (hwy) = 38mpg IMP = 7.35 l/100km //
Opel/Vauxhall Astra,1.8-liter, 140hp, 5-spd manual - Official figures: 33mpg U. S. (EU combined) = 39.8mpg IMP = 7.1 l/100 km. This model doesn't offer significative difference.

Dodge Caliber, 1.8-liter, 150hp, 5-spd manual - EPA's figures: 29 mpg U. S. (hwy) = 34.8mpg IMP = 8.1 l/100 km //
Dodge Caliber in Europe: 1.8-liter, 150hp ,5-spd manual - Official figures: 32 mpg U. S. (EU combined) = 38.7mpg IMP = 7.3 l/100km. This model has slight differences.

In the case of Ford, we can't compare current models because they're different cars altogether, but the figures were very similar for the 2.0-liter versions of the 5-door model back in 2005. In the case of European cars, the figures are, again quite similar: European VW Passat makes 29.78mpg (7.9 l/100 km) and the EPA assigns 31mpg for higway (7.6 l/100km). Again, not a significative difference.





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    • 1 Second Ago
  • 12 Comments
      • 7 Years Ago
      Besides everything already mentioned we have to look at gearing.
      An Astra sold in Germany may have a lower(numerical) final drive ratio for higher speed driving.
      • 7 Years Ago
      It seems to miss everyone attention a US Gallon is 20% LESS than a European gallon.
      Hence we have 45 gallon drums the Euros have a 50 gallon (or whatever it is in the French measurement)
      The Mercers
      • 6 Months Ago
      For what it is worth, a researcher named Feng An took an IDENTICAL (let me rephrase that, he physically took the same car... the exact same unit) to the USA, Japan, and Europe, and ran it through the local test cycles by using local test labs. It was a MY 2002 Ford Focus. For what it is worth (maybe not much) the thing averaged 30.9 MPG under the USA cycle, 27 in Europe (NEDC), and 22.5 in Japan... beats me how or why! Email me at gearhead40@aol.com and I can send you his document, which explains some of the discrepancy. (Part of the problem seems to be the Japanese cycle never gets to a high enough speed (e.g. 45 mph) for maximum MPG.)
      • 7 Years Ago
      Besides....these aren't "American" cars. They are designed in Europe, built in Europe or somewhere other than America, and driven by everyone else but Americans.

      Sad.
      • 7 Years Ago
      Eurpean cars usaully have smaller engines in them allowing them to get better gas mileage.
      • 7 Years Ago
      The short answer is: they don't.
      • 6 Months Ago
      "The current EU test cycle is considered to give considerably higher results than the latest 2008 EPA test procedure."

      The Honda Civic Hybrid in teh UK is rated at 61.4 mpg, which work out to 51.1 mpg in U.S. gallons. Here in America, under the EPA testing, the Honda Civic Hybrid is rated at 42 mpg in U.S. gallons.

      But mostly the reason why cars in Europe get better mpg is because they offer more engine choices whereas we have only one engine choice: the big one.
      • 7 Years Ago
      Uh, octane ratings are calculated differently. It's the same gas.

      Do your research.
      • 7 Years Ago
      So your rule of thumb is to compare the EPA 'Highway' figure with the EU 'combined' figure?
      That is crazy.

      With careful driving, I have alwasy been able to hit the EU combined figure in my cars with, guess what, combined driving.
      On the highway you can hit the 'extra-urban' figure. Around town the 'urban' figure is possible to acheive. Yes, the EU cycle is quite ideal (no aircon, no extra weight, etc.), but it can be acheived.

      Is there any evidence to support the claim that the EPA cycle is more realistic than the EU cycle?
        • 6 Months Ago
        Phil,
        I've been using this rule of thumb since the EPA update their test methods a fair bit ago and I believe you may be interpreting the rule of thumb as an opinion of the author's rather than based on hard numbers.

        What the author of the article is say is not "You cannot achieve EU extra-urban cycle milage figures in America." Rather, they are suggesting "If you wish to get an estimate of how a car which is only rated in the EU would perform in a EPA test, use the following rule of thumb..."

        To arrive at the suggested rule of thumb, the author isn't stating an opinion but basing their rule of thumb on the inspection of the data that they presented.
        • 6 Months Ago
        More realistic? I dunno. It's tough to say. People's habits vary. Is there evidence the US measure is more conservative? Yes, by far. The Prius is the same car in both places and is rated something like 30% higher in the UK than in the US.

        So, to answer the question the article poses: Do American cars in Europe sip less fuel? Nope. They just use different ratings. And autobloggreen is wise to advise that you don't try to compare EU ratings to US ratings, you just don't end up with any useful comparison.

        Also, to the autobloggreen article writer: 95 RON octane is the same as US 91 AKI octane. 98 RON is a super premium that the US (or at least many US states) doesn't have.
      • 6 Months Ago
      Our fuel is not the same as it is in Europe.

      If you check this article http://www.caranddriver.com/reviews/hot_lists/car_shopping/entry_luxury/2006_audi_a4_s4_first_drive_review they mention that US fuel has higher sulfur in it. I've read about this fact in other places as well. Here is what Car and Driver says:

      "Although FSI does allow engines to run lean air-to-fuel ratios—thus saving fuel—there is a side effect of increased production of NOx. There are catalytic converters that can remove the extra NOx, but the high-sulfur fuel we use in the U.S. contaminates them. There are Audi engines in Europe—including racing powerplants—that use FSI with lean burn, but here, FSI engines run about the same air-to-fuel ratio as port-injected engines. So for us, FSI is short for 'fuel straight injection.'"

      And the European efficiency numbers are more realistic IMO. Think about it: If you really care about fuel economy, you will drive the car lightly and get good mileage. I routinely get European effeciency #s (i.e. "extra urban" LOL) in my German cars even with US fuel. That's because I relax and don't pay attention to the morons around me who are rushing towards that red light. They go right past me letting dollar bills fly out of their exhaust pipe at the same time as their brake disks heat up. We arrive at the red light at the same time.

      On the highway you can get great mileage going a couple ticks over the speed limit, and don't get caught up in senseless tailgating and other bad road manners. I'm amazed that they introduced the new 2008 EPA #s, they must be to encourage bad road manners, illogical behavior, or permanent traffic jams. WTF??? I've always exceeded pre-2008 EPA #s just by relaxing behind the wheel, and enjoying the ride...

      You can get as crappy fuel economy as you want in almost any car. Did you see the Top Gear episode where they pitted the BMW M3 vs. the Prius, and the M3 got better fuel efficiency? It's all about how you drive. Do we really need to reinforce bad driving behavior by lowering our EPA numbers?

      I'm still pissed at the EPA for doing that.