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Thread: Wethead Fuel requirements - Premium gas only?

  1. #1
    I am the .45% DBCasey's Avatar
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    Question Wethead Fuel requirements - Premium gas only?

    I thought i read in an article about the WC engine saying that it required Premium (93 or better) octane fuel.

    Can anyone confirm/deny that for me please?

    Many thanks,

    DC
    Last edited by DBCasey; 08-19-2013 at 08:46 PM.
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    Registered User dancogan's Avatar
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    Here's what it says on the back cover of the Rider's Manual:

    Recommended fuel quality Super unleaded, (max 10% ethanol, E10)
    89 AKI (95ROZ/RON)
    89 AKI

    Alternative fuel quality Regular unleaded (restrictions with regard to power and rule consumption. If the engine should for example be operated with 90 RON in countries with lower fuel quality, the motorcycle must be respectively programmed first by your authorized BMW Motorrad retailer.)
    87 AKI (91 ROZ/RON)
    87 AKI


    Now, if someone, once again, would explain the numbers, I would appreciate that. My pumps tend to say 87 (regular) 89 (or 91) and 93 (premium).
    Last edited by dancogan; 08-20-2013 at 12:31 AM.
    Dan

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    Quote Originally Posted by DBCasey View Post
    I thought i read in an article about the WC engine saying that it required Premium (93 or better) octane fuel.

    Can anyone confirm/deny that for me please?

    Many thanks,

    DC
    There's no 93 in California, either. Best we get is 91.
    2000 R1100RT / 1987 K75C (RIP) / Santa Clarita, CA

  4. #4
    Hammam
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    RON is the European standard. PON is the American standard.

    95 RON equals 91 PON.

    See it here:

    http://thoms1.net/Ford/Reference/RONMONPON.html

  5. #5
    I am the .45% DBCasey's Avatar
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    I wonder if the good folks who make the GS-911 will make a software update allowing it to change the fuel requirements? Not many gas stations sell premium fuel out in the "kuds" of Mongolia, Mexico or Africa
    .
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    Registered User lkchris's Avatar
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    So many folks appear to look at a premium fuel requirement as some sort of insult or deal breaker, but it's in fact a sign of an efficiently running motor. Compression = efficiency. Out in Mongolia better have plenty of fuel, as the bike will run through lots of it running at reduced efficiency.
    Kent Christensen
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  7. #7
    Cam Killer marchyman's Avatar
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    I'll repeat what dancogan wrote in different words: Premium is NOT required. AKI 89 is required per the manual. AKI 89 is NOT premium.

  8. #8
    Polarbear Polarbear's Avatar
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    Regular too;

    I don't own one, but coming back from the far North just recently, you will find only regular at dozens of stops up there. Im certain the new engine can handle the regular without much issue, on occasion. Glad my current gsa1200'07 cares less whats in tank. It runs anything, no complaints. Any world class mc should be able to, imo. You may have to alter your throttle manners a tad if the new engine burbs on regular, less aggression in the throttle until you find higher octane again. Just another oversight by BMW to produce an engine that needs higher performance fuels! Guess they ignore folks riding their bikes in far away places with no such gasoline. I also figure the regulations of such places as California plays a BIG part in nations around the world building vehicles/bikes!!! So the whole world follows the few and the extreme clean gets sold everywhere. STILL, you don't have to travel far to find regular gasoline ONLY, even in the lower 48 states. Its becoming moreso...Randy

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    Registered User alan.coles's Avatar
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    While the manual does allow for running 89 AKi/PON or whatever the far-too-many standards are (89 in North America). My concern with running anything below 91 in North America is the Ethanol content which isn't supposed to be good for motorcycle engines.

    IIRC, almost all gas in CA has ethanol added @ 10%~, and all other states either follow suit or allow it in 89 and 87. There is however a growing problem with stations blending in more than the allowed 10%. If you could be certain you were getting ethanol-free gas than you'd have a different discussion. Because that isn't usually possible, I'm more comfortable using 91 to be safe.

    Fortunately, for me, in Nova Scotia and most other provinces, they don't used ethanol in 91, only in 87 and 89, so it is an easy decision for me. Use 91 and avoid ethanol.

    BTW, the octane requirement isn't really a sign of power/efficiency. It is a combination of combustion chamber design. Higher octane is harder to burn and therefore will withstand higher compression pressures before detonating than lower octane will. However, many well engineered engines can easily run 89 octane (NA) with higher compression using good cylinder-head design. Ford's DuraTec 3.5L was on the Ward's 10 Best Engines list for 2007 when it was introduced. The normally aspirated version runs a 10.3:1 compression ratio, produces 265HP and 250TQ using solid-lifters and running on 87 octane. When introduced it had the best figures in the world for running 87 and, I believe, was as good or better than anything running 89.
    Last edited by alan.coles; 08-23-2013 at 06:17 PM.

  10. #10
    Hammam
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    Quote Originally Posted by alan.coles View Post
    While the manual does allow for running 89 AKi/PON or whatever the far-too-many standards are (89 in North America). My concern with running anything below 91 in North America is the Ethanol content which isn't supposed to be good for motorcycle engines.

    IIRC, almost all gas in CA has ethanol added @ 10%~, and all other states either follow suit or allow it in 89 and 87. There is however a growing problem with stations blending in more than the allowed 10%. If you could be certain you were getting ethanol-free gas than you'd have a different discussion. Because that isn't usually possible, I'm more comfortable using 91 to be safe.

    Fortunately, for me, in Nova Scotia and most other provinces, they don't used ethanol in 91, only in 87 and 89, so it is an easy decision for me. Use 91 and avoid ethanol.

    BTW, the octane requirement isn't really a sign of power/efficiency. It is a combination of combustion chamber design. Higher octane is harder to burn and therefore will withstand higher compression pressures before detonating than lower octane will. However, many well engineered engines can easily run 89 octane (NA) with higher compression using good cylinder-head design. Ford's DuraTec 3.5L was on the Ward's 10 Best Engines list for 2007 when it was introduced. The normally aspirated version runs a 10.3:1 compression ratio, produces 265HP and 250TQ using solid-lifters and running on 87 octane. When introduced it had the best figures in the world for running 87 and, I believe, was as good or better than anything running 89.
    I guess the compression ratio of the new LC is 12,5:1 as opposed to 12:1 for the previous GS 1200 boxer. The manual recommends Super unleaded 95 RON (which is 91 PON in North America), AND up to 10% ethanol max. So I wouldn't be too concerned about ethanol, since 10% is what is mixed in our fuels. That being said, I always try to find some 91 without ethanol, just for the sake of it. Shell, for one, offer ethanol-free 91 fuel. With my previous boxers (1200 GS and RT) I used to run 93 PON, because that's what the manual recommended, and only Petrocan and Sunoco offer it, but then they also add some kind of additives in it, which my chief mechanic advised against. So, I went down to 91 PON. And now I see that BMW have built a new boxer engine with both a higher compression ratio and a lower octane requirement. Plus tolerance for ethanol. Good.

    But I do have some put-putting at deceleration. Am I the only one?

  11. #11
    Registered User lkchris's Avatar
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    Ethanol content isn't relevant since it's an octane enhancer in any event.
    Kent Christensen
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    '12 R1200RT, '02 R1100S, '84 R80G/S

  12. #12
    Registered User GKman's Avatar
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    Curious, do these engines have detonation (knock) sensors?
    Many automotive engines do and can retard the timing when detonation is sensed.
    Good system, allows high compression for high power and efficiency but protects the engine from quick destruction from detonation.

    If not I'm curious how these BMW engines control mixture and timing to limit detonation with the high compression and fairly low octane tolerance.

    Some sketchy and some simply bad information above.

    Ethanol content which isn't supposed to be good for motorcycle engines. Not good for in what way? I think that is simply left over prejudice from when some manufacturers didn't do their homework when ethanol was introduced and redesign to accommodate it. If you want to dislike it because it doesn't contain as much chemical energy as gasoline and therefore reduces milage, so be it. Dislike it all you want.

    Higher octane is harder to burn Higher octane is slower, not harder, to burn

    ".. the new engine can handle the regular without much issue, on occasion." Engines don't have any memory of the past or prediction of the future. They don't remember the octane of the last tankful nor know the the next. If the octane is low enough to produce detonation the occasion better not last more than a few seconds or the extreme pressure and temperature of combustion ignition will destroy a piston. Pistons melted down to the top ring were common paperweights in motorcycle shops before the "Our insurance does not allow customers in the shop area" signs came in.

  13. #13
    Registered User lkchris's Avatar
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    Quote Originally Posted by GKman View Post
    Higher octane is harder to burn Higher octane is slower, not harder, to burn
    Yes.

    Hence better resistance to pinging, hence ability to work with higher compression, hence ability for more ignition advance.

    All things that result in a more efficient and at same time more powerful engine.

    Seems silly to give that away using low octane fuel. No question that if an engine "adjusts" for low octane fuel, it adjusts to a state of lower power and less efficiency. TINSTAAFL.
    Kent Christensen
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    '12 R1200RT, '02 R1100S, '84 R80G/S

  14. #14
    Registered User 36654's Avatar
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    Quote Originally Posted by lkchris View Post
    Ethanol content isn't relevant since it's an octane enhancer in any event.
    No, no, no............... one must never apply factual information to a fuel or oil thread........This one is going viral



    On a serious note, I think this new Wethead fuel recommendation is just about the same as the one for my old 86 K75c, 99 R11RS or my 2003 330i....
    Last edited by 36654; 06-23-2014 at 09:00 PM.
    Cave contents: 99 R11RS, 2013 Toyota Tacoma, 03 Simplicity Legacy, 97 Stihl FS75, Dewalt DW625 & DW744

  15. #15
    roamingbeemer roamingbeemer's Avatar
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    My understanding is that ethanol is an issue during storage for periods more than a month or so.

    All of my BMWs have had knock sensors to retard the ignition timing in case of detonation but of course I try to avoid it.
    Seek Fun. "Any fool can criticize, condemn and complain--and most fools do" BF
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