Engine Spec difference between North America and Europe

[autoque]

What's the deal with that? I'm talking about the gasoline engines.

European spec'd 3.0si and 4.8i have 272 and 355 horsepowers respectively.

North American models have 260 and 350 horsepowers.

Does BMW tune these engines differently for each market? Or is it just because European countries have access to higher octane rated gasoline and higher octane makes these engines give out more power?

[X5audi]

There is no actual difference in power (I think), it's just the different rating systems used by the continents.

If I'm wrong, then it's because they do tune engines differently--Europeans prefer sportier vehicles.

[vinuneuro]

Tuned differently for emissions.

[erick_c]

^ Aye.

[AzNMpower32]

It's the conversion difference.

Germany and most of Europe go by PS, or bhp.

http://en.wikipedia.org/wiki/Horsepower#PS

That's why I mention the 335i has 306bhp and 306 PS, which is approx 300 US hp.

[rvas69]

It may also be a different octane rating of gasoline,
Supreme gas in Europe is 95, sometimes even 98...

[JCL]

Originally Posted by rvas69

It may also be a different octane rating of gasoline,
Supreme gas in Europe is 95, sometimes even 98...

No, the fuel is the same. It is the measurement that is different. 98 RON = 92 AKI in North America.

AzN had it right, the spec is different for hp measurement in Europe and North America. The tune is the same, they make the same actual power. Think of the Euro horses as smaller than the North American ones.

[autoque]

Originally Posted by JCL

the spec is different for hp measurement in Europe and North America. The tune is the same, they make the same actual power. Think of the Euro horses as smaller than the North American ones.

I see. But then why is there a bigger difference with 3.0si engine (12HP difference) than 4.8i (5HP difference)? If Euro horses are smaller, shoudn't 4.8i have a lot more than 355 since even the 260 American horses have 272 horses in Europe? If the number is bigger, then the discrepency should also increase...

[JCL]

Originally Posted by autoque

I see. But then why is there a bigger difference with 3.0si engine (12HP difference) than 4.8i (5HP difference)? If Euro horses are smaller, shoudn't 4.8i have a lot more than 355 since even the 260 American horses have 272 horses in Europe? If the number is bigger, then the discrepency should also increase...

Good point. The direct conversion results in 350 hp = 355 hp (PS) The 3.0si at 272 hp (PS) should be 268 hp by a mathematical calculation. There are several possibilities. One is that the engines are actually different. That is possible, but not likely. It is true for the 2009 diesels, which are built to different emissions standards. The second possibility is that the tests were run a different year, according to a different test standard. There are many definitions of hp, all different. On top of the actual quantitative measure, the various tests have different rules about air intake systems, exhaust systems, and so on (since they are bench tests, not in the vehicle). SAE changed their J1349 test standard (which I used at work for years) in 2005, and some engines are rated on the old system, others on the new SAE J2723 standard. There are lots of reasons that the hp that is published for two vehicles sold in different markets won't compare directly, but remember that the engines (of a specific displacement and model) all generally come down the same production line, and only end up in a European or US vehicle based on the luck of the draw.

[X5audi]

Originally Posted by JCL

No, the fuel is the same. It is the measurement that is different. 98 RON = 92 AKI in North America.

AzN had it right, the spec is different for hp measurement in Europe and North America. The tune is the same, they make the same actual power. Think of the Euro horses as smaller than the North American ones.

Actually, I was first