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Author Topic: Why not 93 Octane  (Read 3583 times)

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Online TheBear

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Re: Re: Why not 93 Octane
« Reply #40 on: August 13, 2016, 08:13:38 am »
I must have done more than 30000km inland on my 2008 1200GS without any knocking/pinging/detonating/cavitating or salivating. Note, I did have a wunderlich fuel controller fitted to prevent the bike from running lean.

Our i20 with a 10.5 compression ratio also runs permanently on 93. currently at 120k km
The modern engpines in both your i20 and BMW have knock sensors that retard ignition timing when you run on a lower octane fuel. Its not a problem.
 I ran my 1190 on 93 and although it sounded a bit different and had a little less power the motor was fine.

Well, my LC does make a noise, call it knock or ping, or whatever (I don't know which is correct), on 93 octane that it does not do on 95.  That said, it only does so under more extreme conditions, say hard acceleration in 6th gear from 90 or 100.  So does my wife's.  So, although I cannot see using 93 will damage anything as long as you do not ride into those mentioned conditions, I prefer 95 as that then disappears.
In america I think you can get your hands on toluene quite easily, which when added to petrol boosts octane rating. Here is SA you pay your socks off. In europe in some countries you can get up to 100Ron, but it's of course more expensive. Pinging is less likely inland in winter. It's a distinct sound, someone described it sounding like a can of spraypaint being shaken (with metal ball to mix paint). The boxer do make other noises, it's not a quite engine, but if the noise goes away when you use 95 instead, then it's probably pinging. Strange that the knock sensors don't sort it out. Perhaps inquire at bmw about alternate fueling maps? Or.. Just keep using 95. Don't think car engines can be compared to modern bikes engines. If you think about it, there no 1200cc car engine that makes 92kW. Usually at least a 1600cc Four cylinder. Bike engines are more likely to ping/knock

Thanks Volroom. 

It is pinging, in my opinion, but since I saw the description of the differences (knocking versus pinging) above I am not sure what to call it.  For this discussion, let us call it pinging.  In my day, it was called pinging and easily solved by retarding the ignition timing.  I do know the engine noises of a boxer well and it is not just another noise.  I think, perhaps, the knock sensor may be a tad slow for a bike when accelerating suddenly and hard. 

It doesn't bug me much as I use 95 anyway.  I am a manual type of guy and the manual suggests 95.  I do however live in a town with only one small garage with one bad manager and they sometimes run out of 95, then I use 93.  In fact, on a tank of 93 at present so I am playing with it, due to this thread.  In the morning, no problem, but when I ride it is about 0 - 10 degrees.  In the afternoon, some pinging if I hit the accelerator hard, say in 6th, but under 120 or so, especially if uphill.  Afternoon temps at present  about 25 - 27.   Of course, easily avoidable, by not ripping open the throttle in 6th, on an uphill, when going slowish.




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