Differences in Octane! I tried this and WOW!

[PIMPMYFZR]

well in my case in detroit we have up to 110 but a place around the corner from me sells 104 . at like $6 a gallon . well one day i put a gallon of that and 3 gallons of premium .. dont know what it broke down to but my bike is stock with a slip on and ignition advancer .. seems like the throttle wasnt as choky as before but all in all i think it was just in my head really .. ive heard that xylene is basically what they use in it .. so goto your local paint store grab a gallon of xylene and a 5 gallon gasoline tankwit premium gas , mix it all together and you can have like 105 octane gasoline .. dont do this though because it was hearsay and never tried this or no anyone that has .

[noshoes]

You can get higher octane gas (98-103) at your local airport. Not as much coin as race gas.BTW less than .6% of fuel sold in US has lead in it (as of 1995) and a V&H power pack does map and adjust ignition...With higher octane the fuel preheats LESS during compression
so even if the compression didnt change the second highest setting on the PP would advance the timing enough to feel the difference....

[manveru]

High octane means slow burn, and you should always run the minimum octane level you can get away with. Octane is simply a fuel's resistance to detonation, and a higher-octane fuel must be com-pressed more to burn at the same rate as a lower-octane fuel. Likewise, a faster-burning fuel always makes more power up top.

[noshoes]

High octane means slow burn, and you should always run the minimum octane level you can get away with. Octane is simply a fuel's resistance to detonation, and a higher-octane fuel must be com-pressed more to burn at the same rate as a lower-octane fuel. Likewise, a faster-burning fuel always makes more power up top.

Higher Octane means the fuel can be compressed more BEFORE it pre- detonates!!!!! When you compress a fuel it heats up the more you compress it the hotter the fuel gets!!! If you put low octane in a high compression motor the air/fuel mixture will heat up to much and pre-ignite...Pre-ignition is from a hot spot in the combustion chamber such as a carbon deposit or spark plug that is over heated. As for slower burning in high octane fuel thats because it preheats less than lower octane fuels...A FZR 600 stock compression rate is around 12 to 1 off the top of my head.

[manveru]

detonation-as used in an automobile, indicates a hasty burning or explosion of the mixture in the engine cylinders. It becomes audible through a vibration of the combustion chamber walls and is sometimes confused with a ping or spark knock

preignition-the process of a glowing spark or deposit igniting the air/fuel mixture before the spark plug

just to clear things up

those are both word for word definitions out of Automotive technology 4th edition by jack erjavec, which is used for teaching auto techs for ase certification, following natef guidlines

[Luke-a-Tron]

The point about lower octane burning faster is true for pump gas. With race gas, they put in other chemicals (not sure what exactly) that either directly provide oxygen (molecules that break apart under pressure that let free oxygen molecules loose) or enable oxygen to move around with less resistance at the molecular level. This means the oxidation reaction occurring can go faster. Some of these chemicals require much higher levels of pressure and temperature than a stock motor can provide to do their job. If you ran the 110 octane, your performance might actually go down vs pump gas.

As far as the fuel/air charge getting hotter with lower octane gas, that's incorrect. The reason the mixture gets hotter when it's compressed is because you're taking all the energy that was in the uncompressed cylinder and putting it in a much smaller space. The energy, aka, the heat held in mixture is contained in the random jittering of the molecules. When it's uncompressed they have a lot of room to move around and interact with each other relatively infrequently. Once you jam them all together they are slamming into each other at much higher rate. And since they have less room to move they are banging into each other with more force*.

A high octane hydrocarbon molecule has more uniform bonds between it's pieces and less week points. It can take a lot of slamming around before it snaps. A low octane fuel will snap the weak bonds, which releases energy in the form of slamming around the molecules in it's vicinity. These in turn break more bonds and release more energy until the stronger bonds start breaking and now everything is going ballistic. Oxygens start swapping places left and right with various carbon arrangements and so much energy is being released so quickly, you get fire, AKA really excited molecules.

That's what happens in a pre-detonation scenario. When everything is working correctly the spark plug releases a very large amount of energy in small region of mixture that kicks off the whole chain reaction. The bad thing about pre-ignition is that can start while the piston is till moving up creating a shock wave that slams into the piston. The other bad thing is can start in two places at the same time. If there is not a single flame front, where the shock waves come together creates a much higher level energy. Possibly higher than engine materials can dissipate, at which point something breaks.

OK, class dismissed.



* I'm leaving out quantum details here to keep it relatively simple.

[manveru]

heres a good basic article on race fuel


http://www.chevyhiperformance.com/techa ... index.html

[PIMPMYFZR]

The point about lower octane burning faster is true for pump gas. With race gas, they put in other chemicals (not sure what exactly) that either directly provide oxygen (molecules that break apart under pressure that let free oxygen molecules loose) or enable oxygen to move around with less resistance at the molecular level. This means the oxidation reaction occurring can go faster. Some of these chemicals require much higher levels of pressure and temperature than a stock motor can provide to do their job. If you ran the 110 octane, your performance might actually go down vs pump gas.

As far as the fuel/air charge getting hotter with lower octane gas, that's incorrect. The reason the mixture gets hotter when it's compressed is because you're taking all the energy that was in the uncompressed cylinder and putting it in a much smaller space. The energy, aka, the heat held in mixture is contained in the random jittering of the molecules. When it's uncompressed they have a lot of room to move around and interact with each other relatively infrequently. Once you jam them all together they are slamming into each other at much higher rate. And since they have less room to move they are banging into each other with more force*.

A high octane hydrocarbon molecule has more uniform bonds between it's pieces and less week points. It can take a lot of slamming around before it snaps. A low octane fuel will snap the weak bonds, which releases energy in the form of slamming around the molecules in it's vicinity. These in turn break more bonds and release more energy until the stronger bonds start breaking and now everything is going ballistic. Oxygens start swapping places left and right with various carbon arrangements and so much energy is being released so quickly, you get fire, AKA really excited molecules.

That's what happens in a pre-detonation scenario. When everything is working correctly the spark plug releases a very large amount of energy in small region of mixture that kicks off the whole chain reaction. The bad thing about pre-ignition is that can start while the piston is till moving up creating a shock wave that slams into the piston. The other bad thing is can start in two places at the same time. If there is not a single flame front, where the shock waves come together creates a much higher level energy. Possibly higher than engine materials can dissipate, at which point something breaks.

OK, class dismissed.



* I'm leaving out quantum details here to keep it relatively simple.

i think Luke is a scientist
, like how the hell u ppl know all this stuff .. i just see it at the pump and put it in the tank because i dont know what the hell it is and want to see if it will do somthing differnet then the normal stuff

[noshoes]

detonation-as used in an automobile, indicates a hasty burning or explosion of the mixture in the engine cylinders. It becomes audible through a vibration of the combustion chamber walls and is sometimes confused with a ping or spark knock

preignition-the process of a glowing spark or deposit igniting the air/fuel mixture before the spark plug

just to clear things up

those are both word for word definitions out of Automotive technology 4th edition by jack erjavec, which is used for teaching auto techs for ase certification, following natef guidlines

Ya I realized I switched them around on my ride to work. Its been awhile since I've thought about it but thanks for the "as used in an automobile" book definitions....The term I had a problem with as used on a motorcycle was faster burning or even your "hasty burning" from your ase book isnt a correct term. Detonation isnt to fast its premature. 87 octane in a 9:1 motor will burn at the same rate as 93 octane in a say 16:1 motor. Now I cant find it right now because it was 18 years ago but thats pretty much what it says in my old M.M.I text book the one I used to get my basic, advanced,F.A.S.T.,Honda-Tech and Yama-pro certifications back in 90-91..

[Luke-a-Tron]

87 octane in a 9:1 motor will burn at the same rate as 93 octane in a say 16:1 motor. Now I cant find it right now because it was 18 years ago but thats pretty much what it says in my old M.M.I text book the one I used to get my basic, advanced,F.A.S.T.,Honda-Tech and Yama-pro certifications back in 90-91..

The comparison is a little off. If you said as fast a 93 octane in a 12:1 motor it might work but I don't know that a 16:1 motor could even run on 93. That's what the 110 octane is for.

[noshoes]

Ya I was just tryn to make a point that different octane fuels would burn at the same RATE in different motors....Great post on the subject BTW Luke!!!!!

[YAM93]

^^^^^^







my eyes are turning red and i'm drooling on my shoe. just what i deserve for reading all that.

[HeadRush]

I don't live far from a gas station that sells 100 octane, and I used it in my FZR after it was sitting up for a couple of years. It's $6.49 a gallon, so I won't be using it much. I don't use anymore than 2 gallons anyway. Another gas station about 30 min. away sells 103 octane. I think the higher octanes are good for use every now and then to burn up any deposits from using lower octanes.

[haro504]

i did think i knew everything but after reading that i realized the only thing i have to say is i like boobs

[Fartblood]

The term I had a problem with as used on a motorcycle was faster burning or even your "hasty burning" from your ase book isnt a correct term. Detonation isnt to fast its premature. 87 octane in a 9:1 motor will burn at the same rate as 93 octane in a say 16:1 motor.

Generally, thats correct (and the bit about detonation being premature combustion is spot on), especially for petrol. I believe you chaps call it gasoline.

However, the flame-front can move at different speeds in different types of fuels, especially aviation fuels.

You are also correct in implying that a higher octane fuel is inherently no more energetic than a lower octane one, but by being able to withstand higher compression without pre-ignition they can thus can be ustilised more efficiently.

Strewth, this sort of stuff is easy to understand compared to hypergolic fuels which I had to twist my brain round for my masters.