Octane

[vroomr]

My '07 has a label at the filler telling me to use AKI 91 [that's (RON+MON)/2]. My owner's book recommends 98 RON and says 95 RON is acceptable.

When I was at the dealer recently I noticed that the label on a later model's tank said 89 AKI minimum.

I'm just curious--those of you with the 89 AKI label, what does your owner's book say are recommended and acceptable? I wonder if BMW made a technological change or merely a typographical change.

I will continue to put the recommended juice in my baby. Just curious, that's all.

[Caroanbill]

We only have the RON rating down under - I use 98 RON whenever I can, and the bike likes it. Often have to use 95 RON in the bush (and that's often from less well maintained fuel stops) - I do notice the difference in running (smoothness rather than urge) and in economy / range.

I plan my fuel stops reasonably carefully and so I haven't yet had to use 91 RON, even as a top-up (though it has come close). Based on the difference between 98 and 95, I'd be nervous to run it on pure 91 RON ...

[red baron]

To me the most important item is gas without ethalon. My 08 R1200R has no problem with midgrade gas and I have used regular gas without any problems. I believe the computer adjust itself to the various grades. Most likely I will loose some top power. I noticed also that VW in their bochures mentions that lower grade gas is acceptable if one is agreeable to a little less performance. I have several friends who never use premium or even midgrade gas in their MB, BMW and Audis. Anyway my two cents worth.
Peter

[Hanno]

I believe the computer adjust itself to the various grades.
Peter

I suspect, that the computer can not make any adjustment to the various grades, because this engine has no detonation sensors. Correct me if I´m wrong...

I personaly have used nothing but 98RON so far, except that one time when I filled it up with diesed fuel by mistake. (this is what I am used to tank up my cars with..). I can confirm, that it doesn´t run with diesel at all

[qgaex]

AFAIK the engine does have detonation sensors and so can adapt to gas quality by e.g. delaying ignition.
Also BMW confirms that 10% ethanol (like commonly used in France) is not detrimental to the engine. Of course that mixture sllightly reduces economy and range.

Cheers

gaex
+alwayson98anyhow+

[Hanno]

I did the quick web-research and yes, I was wrong and you are absolutely right, there are the knock sensors indeed. In the combustion chambers.
My previous knoledge was based on the fact, that when I took the bike to service last time, I specially asked them to check if there is nothing wrong with the knock sensors, and the technitian stated that there wasn´t any...
"the BMW authorized service"

regards,
Hanno

[crazyhorse]

i'm a total cheap ass so i have tried to run 87 octane but i can tell a difference when idling and accelerating. i went back to top grade (here in US) 91 and everything is peachy. of course the bike still ran on regular and i would use it no problem if that was all there was available but for my daily commute i'll use the higher octane.

really it's the difference between $13 or $15 bucks (or so) at fillup and i can afford that. just what i do.

wes

[vroomr]

So, anybody come up with why they changed the label on the gas tank?