95 v 98 fuel

My car was imported from Germany so my only handbook is a PDF from the USA. In it says to use Premium unleaded, minimum 91 RON, without knowing any better I assumed that this rating system is universal :? . 95 is higher than 91 so I assumed that 95 would be more than good enough. I looked into it more and now know (as most of you probably already know) that US 91 RON equates to 95 in Europe. For those that didn't know below is info from wikipedia explaining it (there must be one other person out there that didn't know :oops: )

From Wikipedia
In most countries (including all of Europe and Australia) the "headline" octane rating, shown on the pump, is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).


I might try filling up several times on 98 and see if it gets any better. In Spain, certainly where I live the only fuel options I get are 95 and 98, I haven't seen anything like 99 or V max
 
US is a different 3.0 engine to the one in Europe, so their fuel requirements might be less, it's hard to try and compare the two :thumbsup:

I have to say that I don't think I can notice any difference in my SLK, it was just in the Z4.
 
difference only works over time. but if your a light footer, you shouldnt feel much difference. ive been running my car on 98 ron since new and had a friend fill up my car once on 95 ron. not a major problem but the car started to feel its age since i missed all the inspection 1 and 2's until 80k km.
 
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