Fuel octane
Senior Member
Joined: Jul 2006
Posts: 468
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From:
RE: Fuel octane
ORIGINAL: im4u2nv81
theres more to what octane to run than compression. Ignition timing has just as much affect on detonation and such as octane rating does.
If your bike calls for 87/89/73/104, use whats called for OR higher. higher will not hurt, however it will not help either....without changes to ignition timing that a higher octane will allow you to do. Higher octane just has a higher resistance to detonation (pre-ignition), it does not contain a magical power-adder!
Using a higher octane than called for is absolutely useless unless you advance your ignition timing.
Using a lower octane will cause detonation and start eating away at your piston and cylinder head metals.
As the piston goes up in the bore the ignitino ignites the a/f mixture and starts the burn just before the piston reaches the top of its stroke. (keep in mind that there is no actual EXPLOSION happening in the cylinder, its all a controlled burn timed perfectly.) This starts the combustion process. The flame front actually starts to burn while the piston is moving up (BTDC Before Top Dead Center) but does not actually create "power" until the piston has reached the top of its stroke and begins to move down. Detonation, aka pre-ignition, is when the a/f mixture ignites while the piston is too far down the bore and before it starts its "power" stroke.
Lower octanes burn faster and higher octanes burn slower. Therefore, if you run an octane too low, detonation occurs and causes harm. Using a higher octane than needed will do absolutely nothing to help create more power.
Due to the higher octanes burning slower, you can advance the timing (18* BTDC as opposed to 14* BTDC for example) and allow the flame front to start to burn more efficiently as the a/f mixture is compressed and before it starts its downward "power" stroke.
Seems like my post kinda goes back and forth but I've done the best I could to describe why octanes function differently.
This concludes this session of octane discussion. Next session, we introduce BOOST and how it affects a/f ratios and octanes.
theres more to what octane to run than compression. Ignition timing has just as much affect on detonation and such as octane rating does.
If your bike calls for 87/89/73/104, use whats called for OR higher. higher will not hurt, however it will not help either....without changes to ignition timing that a higher octane will allow you to do. Higher octane just has a higher resistance to detonation (pre-ignition), it does not contain a magical power-adder!
Using a higher octane than called for is absolutely useless unless you advance your ignition timing.
Using a lower octane will cause detonation and start eating away at your piston and cylinder head metals.
As the piston goes up in the bore the ignitino ignites the a/f mixture and starts the burn just before the piston reaches the top of its stroke. (keep in mind that there is no actual EXPLOSION happening in the cylinder, its all a controlled burn timed perfectly.) This starts the combustion process. The flame front actually starts to burn while the piston is moving up (BTDC Before Top Dead Center) but does not actually create "power" until the piston has reached the top of its stroke and begins to move down. Detonation, aka pre-ignition, is when the a/f mixture ignites while the piston is too far down the bore and before it starts its "power" stroke.
Lower octanes burn faster and higher octanes burn slower. Therefore, if you run an octane too low, detonation occurs and causes harm. Using a higher octane than needed will do absolutely nothing to help create more power.
Due to the higher octanes burning slower, you can advance the timing (18* BTDC as opposed to 14* BTDC for example) and allow the flame front to start to burn more efficiently as the a/f mixture is compressed and before it starts its downward "power" stroke.
Seems like my post kinda goes back and forth but I've done the best I could to describe why octanes function differently.
This concludes this session of octane discussion. Next session, we introduce BOOST and how it affects a/f ratios and octanes.
Power wheelies is just mashing the gas." AND the whole gearing discusion were i had to put mind boggling numbers on the thread to get my point across....
Joined: Jun 2006
Posts: 57
Likes: 0
From: Vincennes, IN
RE: Fuel octane
Well, well, well. Aren't we all a bunch of bad asses here? Sorry for the delay in my reply.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this?
And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this?
And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
Senior Member
Joined: Jul 2006
Posts: 468
Likes: 0
From:
RE: Fuel octane
ORIGINAL: tcjayde
Well, well, well. Aren't we all a bunch of bad asses here? Sorry for the delay in my reply.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this? And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
Well, well, well. Aren't we all a bunch of bad asses here? Sorry for the delay in my reply.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this?
And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
Joined: Sep 2006
Posts: 77
Likes: 0
From: California
RE: Fuel octane
ORIGINAL: tcjayde
Well, well, well. Aren't we all a bunch of bad asses here? Sorry for the delay in my reply.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this? And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
Well, well, well. Aren't we all a bunch of bad asses here? Sorry for the delay in my reply.
After reading your posts, I have remembered why I hate guys so much. Mainly, I am talking to the canadian guy and the other guy with the ugly *** helmet in his signature. (I don't really care to remember your screennames even long enough to type them.)
Why don't you just bring your happy *** down here to Vincennes, and we can settle this?
And, no, I am not kidding. You guys seem to only settle **** through fighting. So, let's not be a bunch of pussies. And, let's fight about this in person... not over the internet.
Joined: Aug 2006
Posts: 142
Likes: 0
From:
RE: Fuel octane
Fighting?! Who's fighting? We were simply trying to set you and DT straight using facts and simple engine theory and in the process supply some of the others on this forum some info based on fact instead of misguided opinion.
So far as coming to Vincennes to "settle it", how do I respond to that ? Are you really expecting me to jump on a plane and come down to some town where nothing interesting has happened since the 1800's just to beat on a girl. Sorry hitting girls is not the way I roll (no matter how masculine they think they are). Not to mention if I was going to jump on a plane I'd go somewhere with bikini's, sun, sand and tequila not turtlenecks, museums, libraries, and wine.[:'(]
So far as coming to Vincennes to "settle it", how do I respond to that ? Are you really expecting me to jump on a plane and come down to some town where nothing interesting has happened since the 1800's just to beat on a girl. Sorry hitting girls is not the way I roll (no matter how masculine they think they are). Not to mention if I was going to jump on a plane I'd go somewhere with bikini's, sun, sand and tequila not turtlenecks, museums, libraries, and wine.[:'(]
Senior Member
Joined: Jan 2006
Posts: 1,615
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From:
RE: Fuel octane
I told you guys what you were supposed to use in the bikes. You two were arguing that you were supposed to put in 91 and that it was cheap to put anything less in there although it had nothing to do with money.
Plain and simple.
Oh and if you think nothing has happened in vincennes and the surrounding areas, you should really look up what all happens in Indiana and Illinois. We have quite a bit more than you think apparently. Not that I really care what you think but it would just be good to make yourself a little more knowledgeable before you make false accusations about things.
Plain and simple.
Oh and if you think nothing has happened in vincennes and the surrounding areas, you should really look up what all happens in Indiana and Illinois. We have quite a bit more than you think apparently. Not that I really care what you think but it would just be good to make yourself a little more knowledgeable before you make false accusations about things.