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Sorry if this has been asked before 100times...

In Melbourne we have 91ron, 95ron, 98ron, 99ron and 100 available at the pumps.

Is there any benefit to running an octane higher than 91ron? has anyone done comparative dynos with different fuels?

We have 10%ethanol too but i hear this **** degrades rubber parts?
 

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Sorry if this has been asked before 100times...

In Melbourne we have 91ron, 95ron, 98ron, 99ron and 100 available at the pumps.

Is there any benefit to running an octane higher than 91ron? has anyone done comparative dynos with different fuels?

We have 10%ethanol too but i hear this **** degrades rubber parts?
There is no power advantage to running higher octane so I don't believe there is any difference a dyno would pick up but I run 98 in all my bikes and cars - mainly because I get more mileage out of it.
 

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as far as octane ratings go, you won't benefit from running a higher octane rating than needed.

Higher octane= slower burning.

So running a higher octane rate won't give you more power unless you bump up compression, add turbo, nitrous, etc...

I would say run the lowest rate (fastest burning) octane you can without running the risk of detonation.
IMO
 

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It's more correct to say that modifying the engine to require a higher octane is what gives you the power increase. The higher octane fuel doesn't increase power in itself - other than a result of any power enhancing additives in it but again, I doubt the additives provide a dyno-measurable increase.
 

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Higher octane than required will produce less power and leave more deposits. For example, the engine in my 96, with 18K miles, had a ton of carbon on the piston faces and the valves looked horrible, I believe it was the direct cause of my engine failure, a portion of the lip broke off the valve. The guy who owned it before me always ran 93 octane instead of the 87 required.
 

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Higher octane than required will produce less power and leave more deposits.
I disagree as my engines have always stayed clean inside regardless of the fuel I've run. I am starting to wonder though if the high-octane fuels in the US are as good as ours.

Regular oil changes help a lot as the older the oil, the more blow-by you'll get. If you aren't dumping your oil until it's black then you're going to have a dirty engine.
 

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I disagree as my engines have always stayed clean inside regardless of the fuel I've run. I am starting to wonder though if the high-octane fuels in the US are as good as ours.
What's the highest mileage you have seen before opening one up?

Chances are, it's not the quality of the fuel but rather your unrelenting desire to fine tune everything you have. A lot of people just get on them and ride and don't care about carb tuning or valve clearances. I for one am of your school of thought on efficiency.

I make the statement based on my one experience and statements I have read online regarding higher octane fuel. Which basically means you could be right.

Regular oil changes help a lot as the older the oil, the more blow-by you'll get. If you aren't dumping your oil until it's black then you're going to have a dirty engine.
It's entirely possible that the carbs were ill tuned, I know the oil wasn't changed enough and let's not even think about the valve clearances, just generally the bike wasn't taken care of.

But, now I'm familiar with every square inch of my bike and I can ride it with confidence knowing EVERYTHING is right.
 

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What's the highest mileage you have seen before opening one up?
Two of my GSXR750's have over 60,000kms on them and both I bought new and raced.
I have three car engines here now with 280,000kms+ on them. One I just bought is absolutly filthy throughout.

Chances are, it's not the quality of the fuel but rather your unrelenting desire to fine tune everything you have. A lot of people just get on them and ride and don't care about carb tuning or valve clearances. I for one am of your school of thought on efficiency.
While I certainly agree that this seems to be the normal way of "looking after" an engine, I've seen motors pulled down for other people that have run low and high octane fuels exclusively and am not absolutely convinced (despite the advertised claims) that the fuel makes a difference in how clean the engine is. On the other hand I've seen and opened up _many_ engines that were made to live on very dirty oil and it is _never_ good for the engine. I have a 3800 EcoTech motor that went over 150,000kms with _no_ oil changes until it finally spun a rod bearing around the 300,000km mark. The owner simply kept topping the original oil up!

I make the statement based on my one experience and statements I have read online regarding higher octane fuel. Which basically means you could be right. It's entirely possible that the carbs were ill tuned, I know the oil wasn't changed enough and let's not even think about the valve clearances, just generally the bike wasn't taken care of.
Likewise, I'm only commenting from my own experiences and what I've seen and all of those instances may be anomolies as well. A mate of mine is a very talented diagnostic mechanic (absolutely amazing with electrical diagnosis!) and he has built many, many engines and he swears that a very large percentage of problems can be attributed to running low-octane fuels making engines run right at the point of knocking. Fuel octane degrades over time and rapidly if it's not sealed, so a low octane today is even lower a month or two from when it came from the gas pump.

But, now I'm familiar with every square inch of my bike and I can ride it with confidence knowing EVERYTHING is right.
The confidence in your machinery is worth its weight in gold!
 

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Two of my GSXR750's have over 60,000kms on them and both I bought new and raced.
I have three car engines here now with 280,000kms+ on them. One I just bought is absolutly filthy throughout.
Pretty convincing evidence.

The owner simply kept topping the original oil up!
I've known quite a few of those, "But I don't need to change the oil, I keep putting new oil in it." It's truly moronic.

Likewise, I'm only commenting from my own experiences and what I've seen and all of those instances may be anomolies as well.
True, but your experiences far outweigh my own when it comes to this department, after all it is your passion.

A mate of mine is a very talented diagnostic mechanic (absolutely amazing with electrical diagnosis!) and he has built many, many engines and he swears that a very large percentage of problems can be attributed to running low-octane fuels making engines run right at the point of knocking. Fuel octane degrades over time and rapidly if it's not sealed, so a low octane today is even lower a month or two from when it came from the gas pump.
Very compelling evidence to at least run one step higher than what is required in the manual. I actually didn't know that octane degrades over such a short period of time.



The confidence in your machinery is worth its weight in gold!
Absolutely!:thumb:
 

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I've known quite a few of those, "But I don't need to change the oil, I keep putting new oil in it." It's truly moronic.

Very compelling evidence to at least run one step higher than what is required in the manual. I actually didn't know that octane degrades over such a short period of time.
The Ecotech engine was absolutely chock full of thick bitumen-like crud baked onto everything. I was amazed it lasted as long as it did :)

I have never been able to find actual numbers for octane degradation. I assume it's either because it varies greatly due to the additives used by each manufacturer for each of their fuels or because the designed octane rating goes out the window as soon as it leaves the refinery.
I'd love to know for sure.
 

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I agree with all that is stated but, regardless of the octane, they all degrade. So a higher octane will remain usable longer than a lower octane in a production motor...

If we are talking power, higher octane doesn't create more power but may actually decrease power due to it burning slower. We're talking fuel alone in this equation. Now, advancing timing to take advantage of a higher octane fuel MAY increase bhp to some extent but you begin to play with fire. Detonation kills (knock)...

I must say our fuel here is ____ for sure, but the rating is the rating. Octane is derived by the same method worldwide, is it not? Isn't octane in lamens terms the rate of ignition of the fuel?
 

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I've heard that fuel losses something like .6 octane points a week... Just what I heard from a very unreliable source...:rolleyes:
 

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I must say our fuel here is ____ for sure, but the rating is the rating. Octane is derived by the same method worldwide, is it not? Isn't octane in lamens terms the rate of ignition of the fuel?
The rating though is only the rating of the octane.
There are lots of other things in different fuels that have different effects, including some claimed to increase the power of the fuel, fuel efficiency and cleanliness.
The octane rating has no effect on those things so it's not inconceivable to see other benefits from "high-octane" fuels that are unrelated to its octane rating.
 

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I agree with all that is stated but, regardless of the octane, they all degrade. So a higher octane will remain usable longer than a lower octane in a production motor...
Yes, that was my point :)
If I buy 98RON this week and don't drive for six months it might only be 91RON by then and still fine for the engine.
If I buy 91RON though, it might be below the detonation threshold of the engine when I come to use it.
 

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as always, you are right. I'm speaking from a standpopint of our fuels here in the US. 91-93 is our highest rating. I'd love to have all those other options...

Yes, additives in fuel may play a huge factor in the equation.

So it may be a question of what octane from what fueling station to get the best performance?:evilaugh:
 

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Yes, that was my point :)
If I buy 98RON this week and don't drive for six months it might only be 91RON by then and still fine for the engine.
If I buy 91RON though, it might be below the detonation threshold of the engine when I come to use it.

Does anything you own really sit unattended for 6 months... that's machine neglect...:smilebig:
 

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Does anything you own really sit unattended for 6 months... that's machine neglect...:smilebig:
Sadly, yes :)
There are only so many hours in a day and so many days in a week. All my toys and projects are way too many for one person no matter how dedicated :)
 
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