What Octane Do You Run?
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cougar694u
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I run a mix of race gas (left over from my car, I pump it out after each race). Usually, I'll fill up with 93, then at half tank, or there about, add the 110 from my car.
IF I had a dollar for everytime I have explained this...
Running HIGHER octane fuel does NOTHING for performance or CLEANING than just using the octane fuel for what your engine NEEDS. Octane is the resistance to detonation due to cylinder pressure. It also SLOWS the burning process of combustion which can lead to MORE deposits, not less if you do not have adequate flame propagation across the combustion chamber.
If all your requirements are for 87 octane, and you still use 93 or higher... you will actually see a deterioration in power and response. This is DYNO PROVEN and can be easily seen in the difference in mileage.
Using the minimal octane available without a sign of detonation is the best performance option you can hope for. Its also the cheapest.
I'm sure there are a bunch of people who will be interested in refuting this post, but I have over a 1000 hours of dyno experience that will back up my claims.
In fact... if you want the best source of detonation suppression, pump gas with methanol injection is the greatest power boost but it does nothing for a stock engine.
Running HIGHER octane fuel does NOTHING for performance or CLEANING than just using the octane fuel for what your engine NEEDS. Octane is the resistance to detonation due to cylinder pressure. It also SLOWS the burning process of combustion which can lead to MORE deposits, not less if you do not have adequate flame propagation across the combustion chamber.
If all your requirements are for 87 octane, and you still use 93 or higher... you will actually see a deterioration in power and response. This is DYNO PROVEN and can be easily seen in the difference in mileage.
Using the minimal octane available without a sign of detonation is the best performance option you can hope for. Its also the cheapest.
I'm sure there are a bunch of people who will be interested in refuting this post, but I have over a 1000 hours of dyno experience that will back up my claims.
In fact... if you want the best source of detonation suppression, pump gas with methanol injection is the greatest power boost but it does nothing for a stock engine.
Narcissus, your information is incorrect on Shell gas, since they are a top tier gas seller, ALL their octanes have to meet the requirements to be a top tier gas seller, do a search on the net on "top tier gas" and you'll see what I am talking about. I think there are three other gas stations that are top tier.
All fuels have cleaners in them now.
My question is why are there 3 grades of fuel. Some gas stations have meters on the pumps to show how much fuel has gone through the pump...and unless a pump also has diesel there are only 2 meters. If there are 3 grades should there not be 3 meters. Makes you wonder if there even is a 87 octane or if it is actually 89 and 93. The ratings are minimums not exacts. Makes you wonder.
My question is why are there 3 grades of fuel. Some gas stations have meters on the pumps to show how much fuel has gone through the pump...and unless a pump also has diesel there are only 2 meters. If there are 3 grades should there not be 3 meters. Makes you wonder if there even is a 87 octane or if it is actually 89 and 93. The ratings are minimums not exacts. Makes you wonder.
Well, this is a repost at least once since I've been active here, and last time it was about the same. 87 is what Suzi built the Busa to run on, its what its tuned for, and you really wont see any benefit from anything else IMHO. As for 92 being "cleaner" I seriously doubt it. More likely where the gas is coming from, if you use a pump thats notorious for being dirty or having water issues thats one thing. Or if your built and tuned for something requiring more/less octane than you might have issues running other than the recommended rating.
Explaination of my opinion: The Busa is a lower static compression (compared to other liter (+) bikes. The Busa has different valve timing events lowering the dynamic compression. Based off that, and the timing, the Busa is able to obtain more efficient burn of intake charge using 87octane than it will 92. The higher the octane, the slower the charge burns in general (if you doubt this, go fill your tank with 110octane race fuel and run the quarter mile compare that to the 87octane run, you will see the race gas is slower). Carbon build-up is a result of improper charge density, too slow of a burn, electrical/mechanical defect...
Now the grey area, like our brains
Modify the Busa, and you may need to run more octane, like increasing the timing, leaning out the AFR, raising the compression (dynamic or static, and definately if both are raised) and lowering the compression out of its efficiency range; all of these actions require a higher octane (except lowered compression which may want lower octane, sans boost and modified dynamic compression) to keep the engine from detonating. Detonation, however slight, will lead to carbon build-up, just as much as too low/high timing (effecting how much and the charge is burnt).
There is much more to this conversation but thats should be enough for now...and I have a migraine.
Charlie
Explaination of my opinion: The Busa is a lower static compression (compared to other liter (+) bikes. The Busa has different valve timing events lowering the dynamic compression. Based off that, and the timing, the Busa is able to obtain more efficient burn of intake charge using 87octane than it will 92. The higher the octane, the slower the charge burns in general (if you doubt this, go fill your tank with 110octane race fuel and run the quarter mile compare that to the 87octane run, you will see the race gas is slower). Carbon build-up is a result of improper charge density, too slow of a burn, electrical/mechanical defect...
Now the grey area, like our brains
Modify the Busa, and you may need to run more octane, like increasing the timing, leaning out the AFR, raising the compression (dynamic or static, and definately if both are raised) and lowering the compression out of its efficiency range; all of these actions require a higher octane (except lowered compression which may want lower octane, sans boost and modified dynamic compression) to keep the engine from detonating. Detonation, however slight, will lead to carbon build-up, just as much as too low/high timing (effecting how much and the charge is burnt). There is much more to this conversation but thats should be enough for now...and I have a migraine.
Charlie
So then if they are mixing to get 89 out of the line....wouldnt both meters move?
Class experiment: If a station you frequent has meters try using 87. shut off pump restart and use 89. The same meter moves but not the 93 meter.
They can not mix it in the ground because if you look at the fuel fill holes there are not enough of those either.
You are a smart dude Charlie!(CAT3 @ Feb. 23 2007,10:16) Well, this is a repost at least once since I've been active here, and last time it was about the same. 87 is what Suzi built the Busa to run on, its what its tuned for, and you really wont see any benefit from anything else IMHO. As for 92 being "cleaner" I seriously doubt it. More likely where the gas is coming from, if you use a pump thats notorious for being dirty or having water issues thats one thing. Or if your built and tuned for something requiring more/less octane than you might have issues running other than the recommended rating.
Explaination of my opinion: The Busa is a lower static compression (compared to other liter (+) bikes. The Busa has different valve timing events lowering the dynamic compression. Based off that, and the timing, the Busa is able to obtain more efficient burn of intake charge using 87octane than it will 92. The higher the octane, the slower the charge burns in general (if you doubt this, go fill your tank with 110octane race fuel and run the quarter mile compare that to the 87octane run, you will see the race gas is slower). Carbon build-up is a result of improper charge density, too slow of a burn, electrical/mechanical defect...
Now the grey area, like our brainsModify the Busa, and you may need to run more octane, like increasing the timing, leaning out the AFR, raising the compression (dynamic or static, and definately if both are raised) and lowering the compression out of its efficiency range; all of these actions require a higher octane (except lowered compression which may want lower octane, sans boost and modified dynamic compression) to keep the engine from detonating. Detonation, however slight, will lead to carbon build-up, just as much as too low/high timing (effecting how much and the charge is burnt).
There is much more to this conversation but thats should be enough for now...and I have a migraine.
Charlie
Tango....good post, I was actually typing my lonely reply while you posted and missed this one, or else I would have simply said +10000000
It is truely dumbfounding how ppl are misled into believing that higher octane will somehow make said machine run so much better, its a sales gimmick as much as a folklore I do believe. Although I have little experience on the dyno like you, I have a couple thousand drag strip passes under my cap of knowledge, and will absolutely stand by the higher octane (than required without detonation) runs slower, its not a theory its fact. Next to meth, I'd put propane! Oh yeah baby, 127 or so octane (yes many sources debate the actual rating) but mixed with nitrous makes for an incredible anti-detonation fuel source
(definately not NHRA legal though 
).
FadeTwoBlack
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I prefer to run 87, but I usually wind up running 89 as that is what my wife's bike requires. We generally fill up at the same time, so I just fill up using the same pump she is on.
However, if I'm alone then it's good 'ole regular 87. As for brands - If available, my station of preference is Chevron (for the additives).
However, if I'm alone then it's good 'ole regular 87. As for brands - If available, my station of preference is Chevron (for the additives).
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