European fuel consumption

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BBCAmerica has been on a freebie this month (WOOHOO), so I caught my first ep of Top Gear in ages. after finishing that one, i decided to watch a couple segments on the website. one of these involved an economy run from Basel, Switzerland to Blackpool to turn on the Park Lights.

it wasn't the economy cars selection (a Polo 1.4 3 banger deisel, a suby with the Boxer Deisel [coming soon over here to the states, I hear], and a deliberate "run out of gas at the house" jag twin turbo), but the listed economy figures.

Polo 75 mpg!!
suby 50

what amazed me more? a twin turbo 4 liter plus Jag doing 30 miles per gallon??!?! even translated to american fuel consumption, that almost TRIPLE what you could squeeze out of an american car with that size engine.

americans have been squeezing the petrol like nuts with the modern cars, lately, but still, we get half of even the jag's rating.

so, what's the secret, besides bloody expensive fuel?
 
Diesel, essentially. A diesel on a long run is way more efficient than a petrol can be. They're less efficient around town (comparatively - they'd still beat a regular petrol car, if not a hybrid) and not very good at all over short runs as they work best when they've warmed up.

And if you actually drive with even a hint of common sense, it's possible to squeeze good fuel mileage out of most cars. I could easily get 55mpg at between 70-80mph on a longer run in my Fiesta because as long as you anticipate and you can keep a constant speed or as close to that as possible, an engine will run at it's most efficient. Likewise, I can get 40mpg without any problems from the MX5 doing 70mph.
 
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That. Plus one or two other things.

European standard petrol/gasoline is 95RON - the equivalent of North American 91 Octane (give or take). If you put standard 89 in your tank, the same car in Europe will probably cane you for both performance and economy. I recently did a pair of 250 mile runs, back to back, with 98RON Super (US equivalent - 93) and Shell VPower Racing 100 (100RON - US equivalent 96) and got 20% better fuel economy on the 100RON.

And EPA ratings are complete nonsense. To be honest, ours aren't much better, but they're slightly harder to beat in the real world than EPA ratings are.
 
there's part of the answer, then. Volks has pulled deisels over here for various golf/Bora equivs, but even with a scroogy deisel,, they're maxed highway at no more than 45. and, contrary to popular belief (to a brit I know), american roads are not "Bone Straight, dead flat 8 lane superhighwways". around here, the side roads are more like the Nurnburgring, but with worse pavement.

I hear the Cetane levels in our diesel are less than the European ratings, and these are reversed from the European standards. apparently, the GOOD diesel goes into construction equipment and farm tractors, and the poor stuff goes into anything on the roads. this doesn't even count what we burn as heating fuel.

again, the more amazing point was Clarkson squeezing (while running hard on purpose) 30 MPG out of a large 4 liter plus twin turbo in a heavy luxury car. your petrol over there must be absolutely pure.

you brits, clear something up for me. a former Friend in Bristol once told me that Leaded Gas was still for sale over there about 10 years ago.
 
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From what I've read, the test cycle (in another words, the attempt to duplicate real-world results on a chassis dynomometer inside a closed-door facility) is also different between the EPA cycle and the European cycle, which also provokes different mileage. Also, generally, their cars a little lighter, with less federally-mandated safety equipment and naturally, the automaker is going to supply a car with the least options and the least-powerful motor to boost numbers (although this would be on either continent).

Generally, the diesels and lesser powerplants that aren't available in the US (too slow for the "luxury car buyer" and/or use diesel fuel) play around with the numbers a little. In 2007-2008, the EPA figures were revised, meaning car salesmen had to do some dancing about when comparing similar cars on the lot with no difference except in model years and Monroney stickers. I'm glad I was in the service department — and not in sales — during that time period!

I can get the EPA figures if I drive conservatively, even more so if I don't use the A/C. But in typical city driving, I get close to the figures by not winding the motor to 5000 rpm on every shift. Basically, obeying the law and keeping along the pace of traffic; not slamming on the brakes for every stop light and mobile chicane helps, too.
 
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Sniffs
you brits, clear something up for me. a former Friend in Bristol once told me that Leaded Gas was still for sale over there about 10 years ago.
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You still can. But only one company sells it and it's only available at 180 sites.
 
From what I understand, the real problem with diesel cars in the US is more of a cultural thing... Americans see diesel as a fuel for trucks, not cars.

Luxury manufacturers (Jag, BMW, Merc, Audi) diesel engines have more than enough outright performance*, whilst consuming less than two thirds as much fuel as a similar performing petrol engine.

*Of course they do have inferior performance to the R/M/AMG/S models from the above manufacturers, but in the real world they perform much more effectively than the lowlier petrol models in the respective ranges.

Diesel is a much better fuel than petrol for almost anything other than sports cars.
 
Sniffs
what amazed me more? a twin turbo 4 liter plus Jag doing 30 miles per gallon??!?! even translated to american fuel consumption, that almost TRIPLE what you could squeeze out of an american car with that size engine.
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Huh? Talked to anybody with an LS-powered Camaro or Vette? With the 6-speed manual trans, you can get 30+ mpg all day long out of the 5.7 and 6.0 cars on the highway. It's all in how you drive it.
 
Duke
Huh? Talked to anybody with an LS-powered Camaro or Vette? With the 6-speed manual trans, you can get 30+ mpg all day long out of the 5.7 and 6.0 cars on the highway. It's all in how you drive it.
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At what speed... 65-70mph where their stupidly long gearing means they are basically just ticking over? And then they do 10-15mpg off the highway no matter how carefully you drive them.

The midrange diesel versions of most European luxo-barges (S class, 7 series, A8) weighing 2,000kg+, with automatic gearboxes, will manage 30mpg in mixed driving. My wife had a BMW X5 3.0d with Automatic gearbox as a company car for a while... even that managed 30mpg over it's life.
 
Stotty
From what I understand, the real problem with diesel cars in the US is more of a cultural thing... Americans see diesel as a fuel for trucks, not cars.
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It is partially that, partially that normal gasoline is usually cheaper, and partially because of this:
oldsmobile-diesel.jpg


Car and Driver also had a pretty good article a couple of months ago that talked about diesels extensively, but I can't remember most of the content.

Stotty
At what speed... 65-70mph where their stupidly long gearing means they are basically just ticking over?
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Long gearing is a perfectly valid way of increasing fuel mileage. It is in fact the exact reason that many companies have come up with 7 and 8 speed automatic transmissions.
 
Stotty
At what speed... 65-70mph where their stupidly long gearing means they are basically just ticking over? And then they do 10-15mpg off the highway no matter how carefully you drive them.
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They'll deliver very high 20s on the highway at 80 mph.

The several I know don't get 10-15 in town when driven conservatively. If you stand on it all the time, you're going to burn more gas. If you shift short, use the torque to skip shift, and don't flex your muscles all the time, you can get low 20s in town... which is just about exactly what I get in my 2.5l 325i.
 
Stotty: yup, diesel is for lorries, not just "trucks", and of course, our big boys only get five or less miles per gallon. after all, they were conceived when diesel was a LOT cheaper than gas per gallon.

Duke. to go with Toronado's post, the US derived diesels were simply dieselized smallblocks in those. and they got LESS miles per gallon than the gas versions. (they've all since been junked, I believe)

as I've had to tell a guy in britan, america's roads do not consist of 8 lane arrow straight flatter than a supermodel roads. this helps completely remove any realistic assumptions about "highway" mileage occuring.

a note to europeans about their higher quality fuels. I've tried some higher grades, occasionally, and not only do they not make a difference, here...the vehicles actually consume MORE gas, instead of less.

I've been hearing complaints that they're "watering down" gasoline so much now that, afyter adding methanol, it's eating the metal fuel lines.
 
Have you taken into account the discrepancy in the size of a gallon in UK / US?

The Imperial UK Gallon (4.546 Litres) is larger than the US Gallon (3.79 Litres), a difference of ~17%.
 
Famine
Clarkson's car was also a diesel.
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And it wasn't that heavy, given that the XJ is all aluminium. The diesel XJ weighed in at 1659kg. An equivalent 7-series, the 730d, is 1900kg. Or 531 lb difference.

Which reminds me Sniffs, the Jag he was testing was a 2.7, not a 4.0. So there's not quite as much engine under the bonnet as you think.

Duke
They'll deliver very high 20s on the highway at 80 mph.

The several I know don't get 10-15 in town when driven conservatively. If you stand on it all the time, you're going to burn more gas. If you shift short, use the torque to skip shift, and don't flex your muscles all the time, you can get low 20s in town... which is just about exactly what I get in my 2.5l 325i.
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Might also be worth mentioning that European "towns" are very different from American ones. Unless you live in New York they're generally nowhere near as gridlocked and certainly not as tight and twisty.

And yes, I've driven in both.
 
(finally catches replies)

Smallhorses: i've known about "imperial gallons" since grade school/primary school. it was the "oops" point in an Encyclopedia Brown story. He'd spotted the fact that a Canadian gas can had been used, and pointed out it was 5 quarts.

Home: since I was watching an old show, there was no resource as to the size of the engine under Clarkson's hood. I had assumed a 4.0 or 4.5 based on the petrol monsters they stick in US market Jags.

the general consumption levels in my experience run thus

2 l 20mpg
3 l 17 "
4 l 15 "
5 l 12 "

modern cars seem to detect no difference in octane levels. the eighties and ninties i've owned previously (during the US's "downtuned for emissions reasons and CAFE standards" era) generally gained 7 mpg upon sticking 89 octane in. my first car, for example, an 85 fox platform Mercury Marquis saloon (think Family Sized Cortina :P) did 16.6 (with 150k on the clock, and needing a new set of spark plugs rather badly) on 87, but jumped to 23.1 on 89. it had a 3.8 V6 with early TBI (then called central Fuel Injection [i think they turned a carb into a throttle body]) and an old fashioned 3 speed auto. weighing only 2900 lbs helped except in the winter, when I had to tote around 300lb of weight to keep traction.
 
Sniffs
Home: since I was watching an old show, there was no resource as to the size of the engine under Clarkson's hood. I had assumed a 4.0 or 4.5 based on the petrol monsters they stick in US market Jags.
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Yup, 2.7, V6, twin turbo. They also put that engine in the S-Type (like the one Clarkson drove around the 'Ring in 10 minutes - same engine) and Citroen used it in the C6. Jag have now replaced it with a 3.0 V6 twin turbo diesel which you find in the XF and XJ.

They're supposed to be some of the best diesel engines on the market.
 

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