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Wethead Fuel requirements - Premium gas only?

DBCasey

Enjoy the ride!
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
 
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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).
 
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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
.
 
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.
 
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.
 
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
 
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.
 
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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.

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?
 
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.
 
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.
 
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....
 
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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.
 
According to BMW, a service provider is supposed to flash the ECU w/ diff air/fuel ratio maps to account for crap fuel in countries less fortunate.
 
got 20K miles on my GSA running 99% regular unleaded.

No problems and the bike works like a charm.

I get anywhere between 39-42MPG depending on speed and/or headwind

I have gotten as high as 45 once but normally it is closer to 40
 
first, higher octane fuel is not harder to burn, does not burn hotter, in fact it usually contains less BTU per gallon. The only thing high octane does is resist combustion by heat of compression. There are other tests for how well and clean a fuel burns. Octane is kind of the opposite of the diesel fuel Cetane index, a measure of how well fuel knocks. Now it can be true that a high octane fuel burns slower, or hotter, or anything, but that relationship is not measured by the octane test and not guaranteed. This is sort of the same thing as saying a high viscosity oil is a better lubricant. You can not assume that a test for a specific parameter such as viscosity is going to affect other parameters in the same way. Ha, I got oil in:dance

There are 2 common octane tests, using a special motor with adjustable compression and robust construction to resist damage from knock. The tests are motor and research. Of the 2 tests , the motor octane test is lugging the test engine under high load, the research is a higher RPM and lighter load. The same fuel tests 5 to 7 points higher on research.

So which is better? That depends. A big low revving engine would be better served with the Motor test, while a high RPM bike engine might have more accurate results with research. American fuel averages the 2, Europe with the trend for smaller higher revving engines goes for research.

In any case, just add 4 to any American fuel grade and you are close enough.

Rod
 
Not a big deal

Ethanol has a high affinity for water (bad), a lower BTU content per volume (bad), higher octane (good), and higher vapor pressure (bad) than petroleum based gasoline. However, you should be just fine using ethanol blended fuels unless you plan to store it for a long time. The only place I would completely avoid ethanol gasoline is on a boat or a rarely used vehicle in a humid location.

Personally I use 91 octane on my bike. Some places sell 91 octane neat and others blend ethanol into 87 octane to make 91 octane. Except for the laws requiring a minimum level of ethanol blending, it's hard to say who is doing what, because it's all about maximizing profit.

I read an BMWMOA article once about someone who traveled to Mexico and could only find 85 octane. They said that the BMWs ran okay on that but not as well as higher octane fuel. So my take on that is use the higher octane if it's around and if not don't sweat it. After all, BMW builds their bikes to travel anywhere.
 
Don't post what you don't know

There is so much misinformation in this thread! Ethanol has been mixed with petroleum distillates for motor fuel for decades. Ethanol is used by itself in high performance fuel applications. 85% (or higher) ethanol is rated at 104 octane. Ethanol mixes with BOTH water and petroleum. Alcohol is a different kind of solvent than petroleum distillates. All these characteristics make it a useful fuel. On the other hand, bare steel fuel tanks will get rusty and some polymer hoses, fittings, and tanks will deteriorate when exposed to ethanol. Also, alcohol burns with a barely visible bluish flame making it harder to detect (and extinguish) in the event of a crash. Racing organizations usually require additives to enhance visibility when alcohol fuels are used on the track.
So, "modern" IC engined vehicles run fine on mixed fuels, but will not perform properly on higher percentage ethanol fuels without modifications to provide higher fuel flow rates. BTW, the same thing is true when using LP or natural gas, but I'm getting off the subject.
If you run your R1200 LC on lower octane fuel that is primarily petroleum, the ECU will retard timing and throttle rate to prevent pre-ignition combustion. That will produce poorer performance and lower mileage. If you run the bike on racing fuel or aviation fuel, the ECU will advance the timing and you will get more performance. (It will also be expensive as hell because you won't get much better mileage.)
I doubt that our paint shakers will run on straight alcohol without significant mods to their programming, fuel pumps and injectors, but they do just fine on 10% ethanol 89 octane from the selfserve pump even in the mountains of western Canada.
 
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