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2018 Stelvio Base 20" yellow calipers
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Discussion Starter #1 (Edited)
If you consider Wikipedia as kind of the general knowledge source to the world, it is an interesting source of what the current definition is and a place to generalize common information about anything. Here's what they are saying about Stelvio: https://en.wikipedia.org/wiki/Alfa_Romeo_Stelvio and a nice summation of engines that are available throughout the world.


Here is an interesting general description of the 'Hurricane' engine family and intended use: https://en.wikipedia.org/wiki/Chrysler_Hurricane_engine including its evolution into the Wrangler and 2019 Cherokee product lines. Early reviews of this new application are very positive. On the 2019 Cherokee, for example, it is a $2000 option from the base 2.4L and 3.2L version of Pentastar.
 

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How come the rest of the world 2.0 T4 (280hp) engine is slightly slower than the North America version with the same output (5.7s vs 5.4s respectively)?
 

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5.4 sec 0-60 mph VS 5.7 sec 0-62 mph?
 

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this Euro vs US variation is usually partly because different emissions laws means they have to tune the engines different, and possibly have modifications to the exhaust / catalytic converters, and partly due to the different fuel they have available there.
 

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this Euro vs US variation is usually partly because different emissions laws means they have to tune the engines different, and possibly have modifications to the exhaust / catalytic converters, and partly due to the different fuel they have available there.
Except it's really not, it's because the test in Europe is 0-100kmh, which is 3kmh faster at the top end than the test in the US and therefore takes a little bit longer. The table clearly shows this, and it has the US equivalent as 0-97kmh as a conversion from 0-60mph. The fuel is also no different, we just use different units to indicate the octane. Europe uses RON, US uses AKI.
 

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Except it's really not, it's because the test in Europe is 0-100kmh, which is 3kmh faster at the top end than the test in the US and therefore takes a little bit longer. The table clearly shows this, and it has the US equivalent as 0-97kmh as a conversion from 0-60mph. The fuel is also no different, we just use different units to indicate the octane. Europe uses RON, US uses AKI.
You are confusing the difference in octane ratings, which while calculated differently in different markets are still essentially the same thing, and fuel formulations, which there ARE differences between Europe and the US markets. Every market receives different formulations throughout the year. The fuel you pump in the summer is chemically different from the fuel you pump in the winter (though I don't remember exactly what those differences are).

European markets similarly have slightly different base fuel formulations from US markets, in addition to the seasonal variability of the formulation the oil companies introduce. It is these formulation differences combined with the different smog / pollution requirements which is the basis for most small variations between the US spec and the Euro spec for vehicles.

For example, depending on the exact formulation an actual gallon of E10 gasoline it can have as little as 97% of the energy contained in a standard reference "gallon of gasoline equivalent", with actual numbers varying between 120,388*- 124,340* Btu/gal
https://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf

"Gasoline blends differ, and therefore actual energy content varies according to the season and producer by up to 1.75% more or less than the average."[20]

As for the 0-60 vs 0-62mph, it might account for 0.1 second, but 2mph is basically the margin of error on those tests anyway, so no chance it accounts for 0.4 seconds of variation. that big of a difference comes down to engine performance.
 

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Except it's really not, it's because the test in Europe is 0-100kmh, which is 3kmh faster at the top end than the test in the US and therefore takes a little bit longer. The table clearly shows this, and it has the US equivalent as 0-97kmh as a conversion from 0-60mph. The fuel is also no different, we just use different units to indicate the octane. Europe uses RON, US uses AKI.
You are confusing the difference in octane ratings, which while calculated differently in different markets are still essentially the same thing, and fuel formulations, which there ARE differences between Europe and the US markets. Every market receives different formulations throughout the year. The fuel you pump in the summer is chemically different from the fuel you pump in the winter (though I don't remember exactly what those differences are).

European markets similarly have slightly different base fuel formulations from US markets, in addition to the seasonal variability of the formulation the oil companies introduce. It is these formulation differences combined with the different smog / pollution requirements which is the basis for most small variations between the US spec and the Euro spec for vehicles.

For example, depending on the exact formulation an actual gallon of E10 gasoline it can have as little as 97% of the energy contained in a standard reference "gallon of gasoline equivalent", with actual numbers varying between 120,388*- 124,340* Btu/gal
https://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf

"Gasoline blends differ, and therefore actual energy content varies according to the season and producer by up to 1.75% more or less than the average."[20]

As for the 0-60 vs 0-62mph, it might account for 0.1 second, but 2mph is basically the margin of error on those tests anyway, so no chance it accounts for 0.4 seconds of variation. that big of a difference comes down to engine performance.
You're right, fuel changes even from supplier to supplier and definitely over a season. Different fuel could account for about 0.1 seconds at the 1.75% seasonal difference you've quoted, and up to 0.2 seconds with the minimum 97%. I would love to know where they carried out the tests and even whether they were done at different times and in different countries before assuming that was even a factor.

Assuming the margin of error is the same for both measurements (and that is highly likely, they were probably using the same equipment), you can actually eliminate that as a meaningful difference. If you simply calculate the difference assuming constant acceleration you would actually get a 0.18 seconds difference. Based on their numbers, 5.4/60 = 0.09, then 0.09×62 = 5.58. Since the rate of acceleration is not constant, and the fact the times are only quoted to 1 decimal place (so are rounded), and 100kmh is actually 62.1mph, I reckon you can include up to an extra 0.1 seconds. Then you get pretty much your 0.3 seconds once you've rounded the numbers (not 0.4 seconds, you are a little off there). I just don't believe tuning will prove to be the difference given the calculations above, but again I would love to know the truth of it.

Whatever the real answer is, the Stelvio is clearly a great car to drive either side of the pond. Pretty sure we can agree on that :)
 

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You're right, fuel changes even from supplier to supplier and definitely over a season. Different fuel could account for about 0.1 seconds at the 1.75% seasonal difference you've quoted, and up to 0.2 seconds with the minimum 97%. I would love to know where they carried out the tests and even whether they were done at different times and in different countries before assuming that was even a factor.

Assuming the margin of error is the same for both measurements (and that is highly likely, they were probably using the same equipment), you can actually eliminate that as a meaningful difference. If you simply calculate the difference assuming constant acceleration you would actually get a 0.18 seconds difference. Based on their numbers, 5.4/60 = 0.09, then 0.09×62 = 5.58. Since the rate of acceleration is not constant, and the fact the times are only quoted to 1 decimal place (so are rounded), and 100kmh is actually 62.1mph, I reckon you can include up to an extra 0.1 seconds. Then you get pretty much your 0.3 seconds once you've rounded the numbers (not 0.4 seconds, you are a little off there). I just don't believe tuning will prove to be the difference given the calculations above, but again I would love to know the truth of it.

Whatever the real answer is, the Stelvio is clearly a great car to drive either side of the pond. Pretty sure we can agree on that :)
Your rate of acceleration calculation misses the key factor that most of the acceleration doesn't take place in the first ~1 second because the engine has not reached it's peak power yet, which means that the quickest part of the 0-60 acceleration is taking place between ~20-45mph for most ICE powered vehicles on the road.

Also, there's another variable that we don't know here, and that's if these numbers are with or without a 12 inch rollout, as that 12" means the difference of 0.2 seconds for a Tesla Model S.


in the end, yes I definitely agree these are wonderful vehicles to drive!! :devil
 

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2018 Stelvio Base 20" yellow calipers
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Discussion Starter #10 (Edited)
Thinking about this, engine management might vary market-to-market. Example: emissions and catalytic converter n/r in some markets, fuel additives (leaded/unleaded, ethanol content, seasonal grades), and even climate or altitude. Example: difference in tow ratings.

I always wondered at Sunoco for example but all of them what proof is there to assure the premium you pay for higher octane grades is verified and opportunities for cheating. Coming from Weights + Measures I can assure you there are many ways and greedy incentives to cheat the consumer.
 
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