2003 Passat - Is Super Unleaded Required?

Yes. Different measurement standards. See

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various references

Reply to
Tom's VR6
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snipped-for-privacy@yahoo.com (Phil Newnham) wrote in news: snipped-for-privacy@mid.individual.net:

A clue is in the previous post. There are (at least) two octane calculations, Reasearch Octane Number (RON) and Motor Octane Number (MON).

In the US, an average is used (RON+MON)/2, or as it usally appears (R+M/2).

In Europe, just the RON is used, and it's always (?) 8 to 10 points higher than MON.

Reply to
Bert Hyman

I think I missed it. While it was a lot of interesting data, I could not find where either reference provide real world numbers. The only numbers I saw were for specific hydrocarbons, not a typical mix nor was there any references for what might happen if you included typical additives, like alcohol. (the second link was the closest)

It was close to what I was interested in however.

Did I miss it or do you have anything closer?

Reply to
Joseph Meehan

You kinda-sorta missed it as it flew past by implication. But here is an even drier site that gets into the additives and even distinguishes between "Octane" as a measure of anti-knock properties, and as a measure of the energy content of a specific blend of gasoline:

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A google search of "gasoline energy content" or API ANSI ASTM (pick one, not all three) Gasoline Standards will give you all sorts of even drier references.

The point at which the mind usually boggles is that point where one has to understand that a gallon one grade of gasoline (by volume) may weigh as much as 500g (one pound, or so) less/more than a gallon of gasoline (by volume) of another grade.... and we are discussing US gallons (3.8 liters).

After that, the difference in energy content becomes easier to understand.

And if you go far enough back in history, you will also find that Iodine was once used as an "octane enhancer" (combustion inhibitor).

Peter Wieck Wyncote, PA

Reply to
pfjw

That accepted, I've often heard it said that a particular car will produce more BHP on standard UK fuel than it does in the same trim on standard US fuel.

Reply to
Phil Newnham

It is unlikely that Euro-Fuels have all the oxygenators and other clean-air additives (as well as alcohol) included in US fuels.

These days, BTW, the "octane" rating has only to do with the anti-knock properties of any given fuel, and not much at all to do with the actual energy content.

Peter Wieck Wyncote, PA

Reply to
pfjw

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