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Discussion Starter · #1 ·
So, ethanol or not ethanol?

with a 12:1 compression what octane does Ducati recommends for our ss?

Thanks

Gents
 

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Premium grade. Ethanol at a max of 10% is allowed. I will run this in it with no hesitation as that's what I've run in my Hyper for years, now, with no problems. I'll run 100% when I run across it, but I'm not going out of my way for it.
 

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Discussion Starter · #3 ·
Premium grade. Ethanol at a max of 10% is allowed. I will run this in it with no hesitation as that's what I've run in my Hyper for years, now, with no problems. I'll run 100% when I run across it, but I'm not going out of my way for it.
thx Mr Se7en
 
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thats what the manual calls out for as well.

"Use fuel with the lowest octane rating 90 (RON+MON)/2. The vehicle is compatible only with fuel having a maximum ethanol content of 10% (E10). Using fuel with ethanol content over 10% is prohibited. Using it could result in severe damage of the engine and motorcycle components. Using fuel with ethanol content over 10% will render the Warranty null and void."
 

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I have access to 92 or 93 octane or 90 octane ethanol free. The ethanol free stuff is more expensive, would you run it all of the time or just the premium stuff?
 

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I have access to 92 or 93 octane or 90 octane ethanol free. The ethanol free stuff is more expensive, would you run it all of the time or just the premium stuff?
Why don't you just do what the manual says? The part is quoted above and says the lowest octane, so why use 92 or 93 when that is not optimal? But if you want less power than the bike has why not ignore Ducati and put a higher octane in it than it needs.
 

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Why don't you just do what the manual says? The part is quoted above and says the lowest octane, so why use 92 or 93 when that is not optimal? But if you want less power than the bike has why not ignore Ducati and put a higher octane in it than it needs.
They don't particularly say that 90 is optimal...that is the minimum. However, yes, using anything higher is a potential waste of money. I plan to use Premium fuel as I have always done in my high compression engines for 20 years. I figure the extra $1.20USD I spend per 150-160 miles won't kill me...or, more importantly, the bike. I would have to go out of my way to find exactly 90 octane fuel, anyway. My local station, Exxon, has 87, 89, 91. I'll stick to 91. My local station that has 100% gas is rated at 91, as well. Traditionally, this has been a touchy subject on forums as it seems everyone has their own experience with octane and how it works for them, so YMMV.

Page 306 of the manual - "Unleaded fuel with a minimum octane rating of 90 (RON+MON)/2."
 

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I have access to 92 or 93 octane or 90 octane ethanol free. The ethanol free stuff is more expensive, would you run it all of the time or just the premium stuff?
Personally speaking only, I would opt for the 100% if the distance or route was equal. I would not hesitate to run the 10% stuff (at either 92 or 93...really anything at or above 90) without question. However, and I'll step on my soapbox for just a second, I personally only use top tier gas (Exxon, BP, Shell, etc)...EXCLUSIVELY. :nerd: This, I have found, does make a profound difference in both my cars, trucks and bikes. The quality is leaps and bounds above others...in most instances. Again, YMMV.
 

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I always use the highest octane rating I can get in my motorcycles, this is usually 98 octane.
Not only a waste of money but also less efficient than using the octane that the engine was designed for. The ignition timing is set for a particular octane and the only way to keep the engine running perfectly is to change the timing for the higher octane fuel.
People think that because it has a bigger number and is more expensive that it is better - not true, it just burns at a different speed.
I had a mate who only used 100/130 octane waste aircraft fuel in his 250 Honda. It lasted nearly 1000 miles before the engine blew.
But your bike, use what you want.
 

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People think that because it has a bigger number and is more expensive that it is better - not true, it just burns at a different speed........But your bike, use what you want.
Like I said, folks can get quite passionate about fuel and oil. :grin2:

I simply can't get exactly 90 octane easily, so with my local choice of 89 or 91, I'm going with 91...and the manual does say minimum. Just sayin'...:wink2:
 

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Not only a waste of money but also less efficient than using the octane that the engine was designed for. The ignition timing is set for a particular octane and the only way to keep the engine running perfectly is to change the timing for the higher octane fuel.
People think that because it has a bigger number and is more expensive that it is better - not true, it just burns at a different speed.
I had a mate who only used 100/130 octane waste aircraft fuel in his 250 Honda. It lasted nearly 1000 miles before the engine blew.
But your bike, use what you want.
It is and I will. Thanks. Modern engines are able to adjust their own timing. Ducati say this engine will be able to adjust its ignition to prevent knocking or pre-ignition on fuels with an octane rating as low as 90. The lower the octane the earlier you get pre-ignition, amazingly a higher octane rating means the fuel will combust later. A super high octane rating will cause the engine to produce more power and heat than it is designed for. This engine will be designed to run on all commercially (general public) available fuels with a MINIMUM of 90. So I'm not running it on something it wasn't designed for.

"The higher octane rating of super or premium unleaded petrol make it burn more efficiently, thus delivering more power for less fuel burned."

"Higher-octane fuels suit high-performance engines where pressures and temperatures are greater and it can therefore be used to up the amount of available horsepower and improve performance – if your engine is built with performance in mind."

"
NRMA’s Haley adds an important caveat to this.

“As a rule of thumb, each octane increase delivers a fuel consumption improvement of about one per cent,” he says."
 

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I use E10 regular fuel from any station. Been doing it for years and years. No engine failure, and I ride daily. It goes against the grain, but it's worked and it costs less. No major savings at the pump but I have to fill up so frequently that it does over time.
 

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It is and I will. Thanks. Modern engines are able to adjust their own timing. Ducati say this engine will be able to adjust its ignition to prevent knocking or pre-ignition on fuels with an octane rating as low as 90. The lower the octane the earlier you get pre-ignition, amazingly a higher octane rating means the fuel will combust later. A super high octane rating will cause the engine to produce more power and heat than it is designed for. This engine will be designed to run on all commercially (general public) available fuels with a MINIMUM of 90. So I'm not running it on something it wasn't designed for.

"The higher octane rating of super or premium unleaded petrol make it burn more efficiently, thus delivering more power for less fuel burned."

"Higher-octane fuels suit high-performance engines where pressures and temperatures are greater and it can therefore be used to up the amount of available horsepower and improve performance – if your engine is built with performance in mind."

"
NRMA’s Haley adds an important caveat to this.

“As a rule of thumb, each octane increase delivers a fuel consumption improvement of about one per cent,” he says."
Are you telling us that the 939 is fitter with a knock sensor as some BMW bikes are? I am not sure if it is or is not.

A higher octane fuel does burn slower, so that makes it less efficient in an engine not designed for it. The best position of the piston during the maximum fuel burn expansion is 90 degrees after TDC. If you use a slower burning fuel then that point would happen later than 90 degrees ATDC and you would not get maximum leverage in the crank, therefore the engine would be less efficient in both power production and economy. This is a very simplified explanation using rough figures. If you were able to advance the ignition timing a little then you could counter this, but then using lower octane fuel would have maximum expansion earlier than optimal leverage on the big end.

Therefore an increase in one point in octane rating could not make anything more efficient, but quite the opposite.
 

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They don't particularly say that 90 is optimal...that is the minimum. However, yes, using anything higher is a potential waste of money. I plan to use Premium fuel as I have always done in my high compression engines for 20 years. I figure the extra $1.20USD I spend per 150-160 miles won't kill me...or, more importantly, the bike. I would have to go out of my way to find exactly 90 octane fuel, anyway. My local station, Exxon, has 87, 89, 91. I'll stick to 91. My local station that has 100% gas is rated at 91, as well. Traditionally, this has been a touchy subject on forums as it seems everyone has their own experience with octane and how it works for them, so YMMV.

Page 306 of the manual - "Unleaded fuel with a minimum octane rating of 90 (RON+MON)/2."
Thats my thing. Is it tuned for 90 or is it tuned for something higher and minimum is the "it will get you by". I know that ethanol is crap, so if the bike is tuned for 90 and I can also run it without ethanol, I think I may have found my fuel of choice.
 
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