US vs. Europe Fuel Economy Numbers

"Snuze: Needs another Swede" (markg) 05/06/2015 at 14:07 • Filed to: None

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In my now borderline obsession with the Polo GTI and other things VW (I don’t even really like VW that much, but I love the thrill of the chase), I’ve noticed something odd.. UK VW’s report consistently higher fuel economy numbers than their US counterparts.

I first noticed this when researching the Polo GTI to compare to the new Golf GTI and ‘85 Golf GTI, from yesterdays article. According to the VW UK brochure, the Polo GTI gets 31/46 MPG with a manual transmission, and 33/50 with the 7 speed DSG. And no, that’s not imperial gallons, I used the L/100km spec (7.6/5.1 manual, 7.2/4.7 DSG) and converted back to good ol’ fashioned ‘Murica units of US miles per US gallon.

These numbers seemed outrageous, and after sharing my research with Patrick in the original article, some other commenters also pointed out the incredulous economy numbers. So I did some more research - I took at look at the US spec Golf GTI vs the UK spec GTI so I could compare 2 known quantities. The US version gets 25/34 (manual) and 25/33 (DSG). The UK car shows 31/46 (manual) and 29/44 (DSG). Again, I went with L/100 km (7.5/5.1 and 8.1/5.3 respectively) and converted back in to US miles per US gallon.

So this leaves me wondering, what in the world causes the UK cars to post such better gas mileage figures? Weight is the same for both cars. One thing I cannot find is the UK transmission specs, so one thought is that the UK cars are geared a little taller. Still, gearing typically doesn’t make up that much of a difference. The other thought is that the Euro testing system is just that much different than the US.

Any Europpos or anyone with experience care to chime in and enlighten me as to why there’s such a discrepancy?

505Turbeaux > Snuze: Needs another Swede 05/06/2015 at 14:10

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uh, Imperial gallons vs regular gallon. Read here http://jalopnik.com/5981938/why-do…

spanfucker retire bitch > Snuze: Needs another Swede 05/06/2015 at 14:11

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Does the UK follow the EU efficiency measurement standards, or do they do their own little thing?

If they follow what the rest of the EU does, those numbers are almost total and complete bullshit. As bad as the EPA tests are, the ones that they do in the EU are even more egregiously awful.

FJ80WaitinForaLSV8 > Snuze: Needs another Swede 05/06/2015 at 14:11

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The euro tests are also a lot easier. That link that 505 posted explains it all.

Arch Duke Maxyenko, Shit Talk Extraordinaire > Snuze: Needs another Swede 05/06/2015 at 14:12

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Imperial gallons, different testing standards, the UK is a bunch of liars

SidewaysOnDirt still misses Bowie > Snuze: Needs another Swede 05/06/2015 at 14:14

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Imperial gallons are larger than ‘Murican gallons, weirdly enough.

RamblinRover Luxury-Yacht > 505Turbeaux 05/06/2015 at 14:17

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No, he avoided that by using the metric mileage numbers.

505Turbeaux > RamblinRover Luxury-Yacht 05/06/2015 at 14:18

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I think the link explains the rest

RamblinRover Luxury-Yacht > Snuze: Needs another Swede 05/06/2015 at 14:20

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California smog tunings?

EPA tests based on a much more intensive cycle

Systems optimized for constant load/speed do quite well at them

Carmakers can BS and get away with it to a degree

RamblinRover Luxury-Yacht > 505Turbeaux 05/06/2015 at 14:21

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Yep, mostly. The gallon/gallon thing was just not applicable in this case, is what I meant.

505Turbeaux > RamblinRover Luxury-Yacht 05/06/2015 at 14:22

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I think it may have been edited because I would have caught that from the get go

RamblinRover Luxury-Yacht > 505Turbeaux 05/06/2015 at 14:24

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That was a possibility, but then again it’s not written in a way that pops out. He may have done one hell of an edit in five minutes, though.

gogmorgo - rowing gears in a Grand Cherokee > Snuze: Needs another Swede 05/06/2015 at 14:26

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I’ve noticed similar trends in the past comparing US market fuel economy numbers to Canadian market ones. I first looked into it many years ago after seeing a Cobalt rated for 53mpg and a V6 Camaro rated for 42 on the highway. I figured at first it was just the difference in US vs Imperial gallons, but even that didn’t account for the entire discrepancy. I was only 16 or so at the time, but what I discovered after further digging was that there was a different testing matrix.

The EPA numbers were determined with higher speeds and more aggressive driving factored in than the Canadian numbers. I don’t remember the actual speeds and accelerations used, but for example, where the EPA highway numbers were representative of driving at say 70mph, the Canadian ones were done at 60mph, and the EPA city numbers would have been at 1/2 throttle acceleration vs 1/3 throttle for the Canadian numbers.

I’d imagine in the UK, where roads are narrower and there’s much more traffic than in Canada, you’d have even bigger differences in the speed and driving styles they were trying to simulate.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > Snuze: Needs another Swede 05/06/2015 at 14:29

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Ok, so you eliminated imperial Gallons (the most common culprit...) here’s the other reasons:

1) Euro/UK test loop is less demanding than the EPA test loop.

2) Euro/UK model is almost always lighter than the US model due to options and safety-equipment.

3) The EPA is a little more serious about telling manufacturers to shove it when they claim ridiculous figures based on theoretical math and idealized circumstances.

Snuze: Needs another Swede > 505Turbeaux 05/06/2015 at 14:34

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No edit, I think you just missed it.

Snuze: Needs another Swede > Arch Duke Maxyenko, Shit Talk Extraordinaire 05/06/2015 at 14:36

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Factored out the Imperial vs. US gallons. As I mentioned, my thought is just in testing methodology. But it must be a hell of a difference in test methodology.

Twingo Tamer - About to descend into project car hell. > Snuze: Needs another Swede 05/06/2015 at 14:38

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Just our daft testing criteria. My Panda was supposed to get 55mpg city, I got closer to 40mpg.

Snuze: Needs another Swede > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 05/06/2015 at 14:38

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1) This is my initial though

2) From what I can tell they are equal. In fact in the sales brochure for the UK Golf GTI, it’s heavier!!! But the UK “empty” weight includes 68kg for a driver, 7kg for luggage, and 90% of fuel. I don’t think they include that in the US. So my guess is weight is a wash, or not enough to make such a drastic difference in economy.

3) Good point, not sure how strict the EPA is compared to the UK or EU regulators.

Snuze: Needs another Swede > RamblinRover Luxury-Yacht 05/06/2015 at 14:39

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All good points, I’d considered the EPA vs. EU/UK test cycle portion. Hadn’t considered manufacturer BS. Also not sure how Cali smog tunings come into play in this. But I live on the opposite coast so I’ve never bothered to inform myself on all that nonsense.

Snuze: Needs another Swede > Twingo Tamer - About to descend into project car hell. 05/06/2015 at 14:42

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Thanks, this is kind of what I’m looking for. In the US most cars meet or exceed their EPA rating, sometimes by quite a bit. I once got 41 mpg highway on a road trip in my Cruze with 4 adults and a trunk full of luggage. EPA rating is 36 mpg.

Also, in the US manufactures perform the test and report the findings, but the EPA is pretty strict about them reporting accurate numbers. Maybe the UK/EU authorities allow more leeway in reporting. So that, combined with a different test cycle, could explain the discrepancy.

RamblinRover Luxury-Yacht > Snuze: Needs another Swede 05/06/2015 at 14:43

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It’s less so these days, but Cali has always led the way on funky requirements beyond the rest of the nation. A bigger cat and a different tune for different NOx and particulate numbers could make for some differences without a doubt, though not so much as in the 80s.

505Turbeaux > Snuze: Needs another Swede 05/06/2015 at 14:45

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ah really, must be getting slow in my old age. There were others that said the same thing and I was wondering if 10 idiots could all be wrong (sorry other people :D )

Snuze: Needs another Swede > spanfucker retire bitch 05/06/2015 at 14:45

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I’m not actually sure what standard the UK uses, but this is a trend I’m beginning to see. I didn’t realize how bad the EU numbers are. Here in the US, I think it’s kind of a wash. Bigger, heavier trucks and SUVs sometimes struggled to meet EPA numbers, but compact cars and relatively efficient minded turbo cars usually exceed their EPA numbers. My 1.4 Turbo Cruze usually gets at least 10% better than it’s rating. In fact my day-to-day average is 37mpg, a lot of which is city and highway stop-and-go traffic, and my EPA highway rating is 36.

spanfucker retire bitch > Snuze: Needs another Swede 05/06/2015 at 14:49

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Someone in a comment explained it to me better, because I too was curious how the EU - using a newer testing standard than the decades old one here we use in the states - could be so far off the mark in terms of fuel efficiency.

It has something to do with the automaker’s ability to game the test with easy to use loopholes, or something along those lines. The EPA’s highway testing speed of 55mph might be ridiculous, but it’s a hard test to try and fudge with, as outdated as the methodology may be.

Hopefully someone here can be more enlightening then the vague generalities I could muster.

Twingo Tamer - About to descend into project car hell. > Snuze: Needs another Swede 05/06/2015 at 14:54

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I never ever saw what my car was meant to get. Over the 1500 miles I had it, I averaged 50mpg split 50/50 city and 70mph roads. My grandad’s car is meant to get about 50mpg and it gets 36mpg and so on. No car ever meets the stated mpg here. We really need to adopt the US method if it gives you a better idea of actual economy, ours are essentially useless.

Shady Balkan Subject, Drives an Alfa > Snuze: Needs another Swede 05/06/2015 at 15:00

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The EU fuel economy is little over the top, but when the stars align, a sacrifice is made to all the pagan gods and you really try it can become reality, even when you think it is impossible. A friend bought a 2014 Mazda 6 with the 2.2 Diesel and manual. On a 550 km trip we averaged 4.5l/100km, which is very close to what Mazda advertize as combined cycle. I mean this is absolutely amazing numbers, for a sedan with 170 kg of meat driving and at least 50 kg of additional stuff. And there was not some grandma style of driving, but a reasonable speeds on 2nd class roads, mostly straight, with not a lot traffic. I was absolutely mindblown.

4muddyfeet - bare knuckle with an EZ30 > Snuze: Needs another Swede 05/06/2015 at 15:04

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You’re welcome to tell me I’m wrong, but could it not be a combination of EU testing procedure and the difference in US and UK standard fuels (therefore different ECU maps)?

Standard UK fuel is RON 95 which is the equivalent of the US AKI 90. If tested using regular AKI 87 with different mapping, that may throw the number out a bit.

Staying with the ECU map, the US spec has to cover a wider range of fuel octane at a lower average octane level, from AKI 87 (UK equiv. RON 91) to AKI 91 (UK RON 96), whereas the UK has to cover from just RON 95 to 98.

Possibly.

Ash78, voting early and often > spanfucker retire bitch 05/06/2015 at 15:45

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I believe the UK extra-urban cycle (or whatever they call it) is like tooling around B-roads at 45-55mph...the sweet spot for max efficiency.

The US EPA highway cycle is a lot of slowing and speeding up from 45-70, IIRC.

I’m too lazy to look it up, but this bugged me about 10 years ago and that was the main factor I came up with. The Euros also have more incentive to game the system to comply with the regs and avoid taxes.

SDKR > Snuze: Needs another Swede 05/06/2015 at 16:01

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In the current EU test, carmakers are allowed to remove alternators, a/c pumps and do other mods. Also it’s done on a rolling road at specific speeds, so they make sure the engine is most efficient at that speed. I can usually match the EU rating, but it takes extremely careful driving and pissing off everyone behind me.
I’ve heard that they are working on a new test.

Snuze: Needs another Swede > Shady Balkan Subject, Drives an Alfa 05/06/2015 at 16:46

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That’s really impressive. I wonder if maybe the EU test is setup in such a way that diesels excel at it?

Snuze: Needs another Swede > 4muddyfeet - bare knuckle with an EZ30 05/06/2015 at 16:49

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I really don’t know the answer, that’s why I’m asking. Im thinking a lot of it has to do with the testing format, the US is just more stringent than the EU. But I did wonder about fuel standards, I know EU generally has better quality, so the thought did cross my minds, but I still don’t think it’s enough of a different to explain all of the discrepancy. It seems like a lot the Euro jalops here are basically saying the EU testing cycle is not very indicative of real world usage so it posts artificially high results. Also, there may be less regulation on reporting, so manufacturers have more leeway to fudge the numbers.

Snuze: Needs another Swede > SDKR 05/06/2015 at 16:50

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Ahh, good to hear. If they do it on a rolling road, they aren’t really seeing any aero load, which is small potatoes for city driving but gets to be more important at highway speeds. That may have a lot to do with the high highway numbers.

Shady Balkan Subject, Drives an Alfa > Snuze: Needs another Swede 05/06/2015 at 17:12

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I am not sure it is like that, diesel engines have around 15% better economy on average on same models, but it is definitely not very strict.

Another funny result was when a friend of mine was driving an E36 320i, which would at best do a little under around 8/100, but one drive to our New Eve’s resort gave 6.2/100 on the board computer, but this was made over a 180km trip mostly on a two lane road at 80km/h moving traffic, so a lot of slip streaming was achieved. Some calculations after, because BMW board computers at that time were not so reliable, showed that we are at around 6.8/100, which for a 90s BMW inline 6 was again absolutely amazing.

Saf1 > Ash78, voting early and often 05/06/2015 at 17:50

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Interesting point about the cycles! Though I actually assumed the opposite... UK cities in general seem more congested and thus more accel/decel? Plus all this 1-way street malarkey...Explain your last sentence pls?

Saf1 > Snuze: Needs another Swede 05/06/2015 at 17:52

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I think it’s purely the test conditions. 550 km tells me lots of motorways, quiet roads inter-city, basically the opposite of a typical accel/decel drive

Snuze: Needs another Swede > Shady Balkan Subject, Drives an Alfa 05/07/2015 at 08:19

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A lot of the discussion I’ve had so far has been about gasoline powered cars, but I agree with you, diesels are more efficient. So I’m thinking perhaps the test is conducted in such a way that better reflects the actual performance of diesel engines but gives artificially high results for gasoline engines.

Also, that’s pretty impressive on the 320i. I had a friend who used to have a mid 90’s 325i (we never got the 2.0 inline 6 in the US) and it was a great car, but you’re right, gas mileage wasn’t its strong point.

Snuze: Needs another Swede > Saf1 05/07/2015 at 08:20

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This is kind of what I’m thinking. I don’t know the test format, but my suspicion based on discussions so far is that maybe the EU test favors diesels. They are inherently more efficient, so maybe the tests provides real world results for diesels while providing artificially high results for gasoline engines.