There are different scales for measuring octane level of fuel
- (=Research Octane Number) used in most of the world (Europe, Australia)
- MON (=Motor Octane Number)
average of Ron & MON (used in the US + Canada + few others)
to compare the numbers with each other one can add 3-5 points to the AKI
(=Anti Knock Index) number used in the US.
so US Regular 87 would be RON 91-92
In Europe this can as far as I know only be obtained in Germany.
Eastern Europe and the (former) Soviet Union had/has quite low numbers
as wel.
In most European countries 95RON (=90-91 US) is considered regular. 98
RON is considered premium (with or without lead(replacement) 102-103
AKI/US value.
Hope this helps
RON
> Most peculiar, since this 91 US, 95 elsewhere is the standard fuel in
> probably all of Europe (haven't been everywhere so can't say). hard to find
[quoted text clipped - 3 lines]
>
> I am speculating that Japan and Middle East not much different.
Dori A Schmetterling - 16 May 2007 18:00 GMT
Thanks for underlining my point: 95 (91 US) is standard where as it seems to
be "premium" in the US.
DAS
For direct replies replace nospam with schmetterling
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> There are different scales for measuring octane level of fuel
> - (=Research Octane Number) used in most of the world (Europe, Australia)
[quoted text clipped - 22 lines]
>>
>> I am speculating that Japan and Middle East not much different.
> Most peculiar, since this 91 US, 95 elsewhere is the standard fuel in
> probably all of Europe (haven't been everywhere so can't say). hard to find
> lower grade, non-existent in UK.
>
> 97/98 octane 9 (c. 93/94 US) is available in many places.
Something to keep in mind is that the lower the octane the more easily
and completely it burns. Higher octane fuel is marketed as something
wonderful, but is only needed if you have a high compression ratio or
aggressive timing. Putting higher octane in than needed is a waste of
money, and you'll likely wind up with worse gas mileage-although
insignificantly worse. Before you all complain, note that I said
"higher octane THAN NEEDED." If you put in too low an octane, you will
also get poor mileage since the engine will knock, then sense that it
is knocking, then change the mapping to prevent knock, and this
mapping will be less than optimal for efficiency or power. Higher
octane gas doesn't have more energy, it simply combusts slower and
less easily, which is what is needed in a high compression ratio or
forced induction engine where you can get knock fairly easily. If you
don't have that type of engine, then you don't need it.
So don't think that America is peddling inferior gas because it is a
lower octane. It is probably more suited to about 98% of the world's
cars than the higher octane stuff sold elsewhere. It may be true that
Europe sees some hotter more tuned cars, but I have trouble believing
that a car company would sell a car so radically tuned that it would
require 103 octane. I could be wrong, and tell me if I am. However, I
felt compelled to defend any implication that American is selling
inferior which is threatening the drivers that buy it.
And there is one important difference between the crossfire and the
mercedes that it was based on. The Crossfire is much more stylish-some
love it, some hate it-but it is definitely different. The Mercedes was
just not all that exciting.
Dori A Schmetterling - 20 May 2007 22:13 GMT
That is exactly the point. Engines elsewhere in the world (outside the US)
are tuned such that they need 95 octane fuel. Lots of hp in relatively
small engines. Also, very few cars need anything higher. The claims for 98
octane fuel are very carefully phrased....
DAS
For direct replies replace nospam with schmetterling
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[...]
> Something to keep in mind is that the lower the octane the more easily
> and completely it burns. Higher octane fuel is marketed as something
[quoted text clipped - 24 lines]
> love it, some hate it-but it is definitely different. The Mercedes was
> just not all that exciting.
Rob - 21 May 2007 04:04 GMT
>> Most peculiar, since this 91 US, 95 elsewhere is the standard fuel in
>> probably all of Europe (haven't been everywhere so can't say). hard to find
[quoted text clipped - 30 lines]
> love it, some hate it-but it is definitely different. The Mercedes was
> just not all that exciting.
It wasn't all of that well made, either, and the Chrysler is a faithful
copy.