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Author Topic: Why not 93 Octane  (Read 3576 times)

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Offline Venter

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Why not 93 Octane
« on: July 29, 2016, 06:07:23 pm »
Hi All,

With the petrol strike just starting yesterday, I already see a predicament approaching. Both my closest petrol garages have run out of 95 octane fuel.

Now the reason for my question, will 93 octane have any negative effects on my bike?
I ride a R1200GS LC, 2014 model.

The manual obviously states the use of 95 octane, but I don't see any mentioning of not to use 93?


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Offline TheBear

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Re: Why not 93 Octane
« Reply #1 on: July 29, 2016, 06:18:54 pm »
Simplistic description.

93 should not damage the bike in any way, as long as you take into consideration that the engine is tuned for 95.  What could happen, but unlikely in mid winter, is that the bike will ping under load.  If it does, just avoid that load, i.e. you accelerate and it pings, accelerate slower, or change a gear down.
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Offline whitedelight

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Re: Why not 93 Octane
« Reply #2 on: July 29, 2016, 06:22:00 pm »
Most modern ECU systems should pick it up and adjust the timing. I would maybe not run it as hard as one would with the higher octane. I am not a professional but that is as I understand it.
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Offline Vicky

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Re:
« Reply #3 on: July 29, 2016, 06:41:07 pm »
Venter, I assume that you are located inland, with 93 being available as an option at the filling station? Being in a location where 93 is availble means that the area is high enough (correct altitude) for your engine to perform perfectly without any concerns. With the "thinner" air (less oxygen) in the highveld, the 93 octane is perfectly sufficient.
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Offline TheBear

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Re: Why not 93 Octane
« Reply #4 on: July 29, 2016, 07:15:30 pm »
So far, the reasons are different, but the outcome is the same.  No damage.

My understand (simplistic again) is that the octane number purely indicates the propensity of the fuel to pre-ignite.  The lower the number, the easier petrol pre-ignited.  Pre-ignition leads to pinging.  Pinging is not good as it is an indication that damage could occur. If the ECU can pick up the issue and adjust the ignition timing accordingly, there will be no issue, except a small loss of performance due to the retarded ignition timing.  I am not sure if the bike's ECU  can do this (don't know if there is a knock sensor on a LC), but even if it cannot and it pings, like I said, just don't push it so hard that it continues pinging.

My experience with both our LC's is that they will ping a tad on 93, but only when pushed hard and so far, only on hot (32+) days.
« Last Edit: July 29, 2016, 07:19:10 pm by TheBear »
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Offline volroom

Re: Why not 93 Octane
« Reply #5 on: July 29, 2016, 09:44:16 pm »
So far, the reasons are different, but the outcome is the same.  No damage.

My understand (simplistic again) is that the octane number purely indicates the propensity of the fuel to pre-ignite.  The lower the number, the easier petrol pre-ignited.  Pre-ignition leads to pinging.  Pinging is not good as it is an indication that damage could occur. If the ECU can pick up the issue and adjust the ignition timing accordingly, there will be no issue, except a small loss of performance due to the retarded ignition timing.  I am not sure if the bike's ECU  can do this (don't know if there is a knock sensor on a LC), but even if it cannot and it pings, like I said, just don't push it so hard that it continues pinging.

My experience with both our LC's is that they will ping a tad on 93, but only when pushed hard and so far, only on hot (32+) days.

just a comment, I think there is a distinction between pre-ignition and detonation (pinging or knocking). pre-ignition you don't want, a hot spot causes fuel/air mixture to ignite when piston is just starting to come up for compression stroke before spark - pre -spark or ignition- basically against the force of hot expanding gases, heating it even more, you engine won't last very long, hole in piston. this obviously does not happen often, if it happens, good bye pistons. perhaps more an issue in the old days. hot spots can be carbon deposits on exhaust valves or glowing electrode of sparkplug or whatever.

Knocking, detonation or pinging (sounds like shaking a spray can of paint with the metal ball) usually under load (heavy acceleration) happens after ignition (spark), but then due to too much pressure I think, the flame front does not spread from the spark plug down as per usual, but elsewhere in the air/fuel mixture ignition starts - and the two shock waves meet causing a much higher peak pressure for a split second which causes greater vibration. knock sensors pick up this vibration through the engine casing I think, and retard ignition timing. I think the LC should do this, even the early 1200GS had knock sensors. In winter time, knocking less pronounced and don't know if anybody noticed, it's friegen cold
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Offline TheBear

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Re: Why not 93 Octane
« Reply #6 on: July 29, 2016, 10:05:43 pm »
Thanks Volroom.  It is all way to complex for me, so I tend to reduce it to a very simplistic level to help me understand.
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Offline Venter

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Re: Why not 93 Octane
« Reply #7 on: July 29, 2016, 10:32:16 pm »
Thanks a lot to all the comments.
I now understand the concept much better and I'm a lot more at ease. I will still try and get a tank of 95, but if not I will just take it easy on 93 for a while.


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Offline 0012

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Re: Why not 93 Octane
« Reply #8 on: July 30, 2016, 07:11:37 am »
Agree with the above, you'll be fine  :thumleft:
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Offline wrench

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Re: Why not 93 Octane
« Reply #9 on: July 30, 2016, 07:33:01 am »
Simplistic description.

93 should not damage the bike in any way, as long as you take into consideration that the engine is tuned for 95.  What could happen, but unlikely in mid winter, is that the bike will ping under load.  If it does, just avoid that load, i.e. you accelerate and it pings, accelerate slower, or change a gear down.

No engine damage can occur by using 93 octane or lower fuel, however 93 is a lead replacement fuel and does contain sulphur. This is a problem for lambda sensors and will with certainty destroy them. With the lambda been damaged by the sulphur, it will read incorrect input voltage and would output the same to the ecu and the afr would be a lash up.
 

Offline Cracker

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Re: Why not 93 Octane
« Reply #10 on: July 30, 2016, 09:01:55 am »
Not quite. We get 93 unleaded (green nozzle) AND 93 LRP (red nozzle)

93 unleaded can be used instead of 95 unleaded as stated above.

93 LRP cannot, except in older (design, not age) non-efi, non catalytic converter engines.

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Offline TheBear

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Re: Why not 93 Octane
« Reply #11 on: July 30, 2016, 09:12:48 am »

No engine damage can occur by using 93 octane or lower fuel, however 93 is a lead replacement fuel and does contain sulphur. This is a problem for lambda sensors and will with certainty destroy them. With the lambda been damaged by the sulphur, it will read incorrect input voltage and would output the same to the ecu and the afr would be a lash up.

You are correct.  I was comparing 93 and 95 Unleaded.  I did omit to warn against 93 LRP.  Thanks.

To be honest, I wasn't even think LRP.  
« Last Edit: July 30, 2016, 09:27:44 am by TheBear »
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Offline Straatkat

Re: Why not 93 Octane
« Reply #12 on: July 30, 2016, 10:22:57 am »
I always use 93 unleaded and cannot tell any difference in performance, all my vehicles go very well and has done so for as long as I care to remember. Maybe I am just a cheapskate.
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Offline Battlestar

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Re: Why not 93 Octane
« Reply #13 on: July 30, 2016, 06:54:45 pm »
For what it's worth all my BMW boxers spluttered, farted and "pinged" when using 93 octane. My single spark 1150 was by far the worse. On my current 1200 I had BMW load a fuel map where 93 octane can be used and have not had another issue with it since.
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Offline Buddy

Re: Why not 93 Octane
« Reply #14 on: August 01, 2016, 07:53:35 am »
Yes, but what does your insurance say?  :)
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Offline ss

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Re: Why not 93 Octane
« Reply #15 on: August 01, 2016, 12:57:29 pm »
Agree wit Straatkat. I have found no difference at all.
 

Offline TheBear

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Re: Why not 93 Octane
« Reply #16 on: August 01, 2016, 01:13:12 pm »
Agree wit Straatkat. I have found no difference at all.

Have to agree in 99,99% of the cases.  My LC definitely pings on 93 when outside temps are high. 
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Offline gee

Re: Why not 93 Octane
« Reply #17 on: August 01, 2016, 01:31:36 pm »
i have been using 93 here in gauteng on my 2015 lc for 20000 k and have not found any problems. I did a bit of reserch on the net and test done overseas in a controled inviroment came up with the conclusion that save your money and use 93
 

Offline Titleists

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Re: Why not 93 Octane
« Reply #18 on: August 01, 2016, 01:45:43 pm »
i have been using 93 here in gauteng on my 2015 lc for 20000 k and have not found any problems. I did a bit of reserch on the net and test done overseas in a controled inviroment came up with the conclusion that save your money and use 93

Your bike will have a bit less power.

Out of interest, the test done overseas, what was the altitude, octane fuel tested, type of engine, compression of engine, ambient temp, air pressure? Those things all make a huge difference to the fuel consumption and power.
 

Offline JustBendIt

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Re: Why not 93 Octane
« Reply #19 on: August 01, 2016, 01:50:40 pm »
Did you recalibrate the APV ?
The older I get the faster I was