87, 89, 93 octane whats the difference?

Me and my English 4 teacher had an arguement on the differences of gasoline and their octane. He was saying that their isn't a difference, and that higher octane doesn't clean your fuel system, and it doesnt improve performance. My return arguement goes like this. 1 Higher octane is more combustable their for giving more explosion and finally more performance. 2 Higher octane doesnt have as many carbon deposits as lower octane, therefor it does clean your engine. 3 I garantee you if you go and get some 108 octane racing fuel you will deffinetely feel some kick, im no fuel expert so write me back and tell me what you think.

Odoesnt clean anything. It does however improve performance to differing degrees depending on the vehicles configuration. If the car has fuel injection then the benifits are pretty minimal unless you use a racing gas of 100+ octane.

Octane, by definition, is the resistance to burn or detonation. The higher the rating, the slower the burn when ignited during the compression burn cycle of the piston. The higher octane allows for better control of burning for high compression engines. So we want to match the correct octane rating of the gasoline to the engine design to ensure complete burning of the gasoline by the engine for maximum fuel economy and clean emissions.

Im gonna say ditto to Yogs, just so i can rack up those posts :D

And yeah, it matches with the car, putting 93 octane in my crapalier would be quite a waste of money and outright bad, but for performance cars its pretty much necessary if you wanna keep your car running right.

I did hear that it helps out as far as keeping your engine going. Not actually CLEANING your engine, but preventing or slowing it from having problems as far as carbon and such goes. Anyway, thanks for the clarification Yogs :)

yeah, as compression in the engine goes up, the octane (resistance to burn) of the gasoline must increase to avoid detonation in a non-computer controlled car. when, say, 87 octane, is put in a car with, say, 11:1 compression ratio, the gasoline will expode on the compression stroke of the engine somewhere before reaching top dead center, before the spark has reached the spark plug resulting in an uneven burn across the combustion chamber. this is bad in a few ways: first, it can and more than likely will competely tear up you engine in a matter of seconds (burned, melted pistons, missing chunks in the combustion chamber, gouged walls... etc.... ) all of which will reduce your motor to scrap in short order. also, pre-ignition (as it is also called) robs power by not allowing the motor to squeeze the intake charge as much as normal, which means a less powerful explosion, and less HP. as the compression in a motor increases, so does the power of the explosion and thus more horsepower is produced. this is why a motor with 11:1 compression ration (ratio of the volume of the cylinder at bottom dead center to the volume at top dead center including the combustion chamber size) will be much stronger than a motor with 8:1

In a computer controlled engine, using a lesser grade of gasoline than optimal for the engine compression ratio will cause the computer in the car to retard the timing, which will then rob you of power.

using a higher octane allows you to take complete advantage of the performance of your car by allowing it to run at the optimal spark advance (time at which the distributor sends the spark to the combustion chamber in order for it to ignite the intake charge at the optimal moment for the charge without detonation) due to the increased resistance to burn, and it is also better for your motor due to it being further refined, detergents, supplements etc.....

Wow, my head hurts now :D

Really though, thanks for knowin your shit so i can now know mine

Originally posted by DementedPuppy
Wow, my head hurts now :D

Really though, thanks for knowin your shit so i can now know mine

I have some good formulas for making your own octane booster. Let me find them, and I will post them. :D

So your saying that the slower burn rate allows the piston to contract the fuel more which in return you have a bigger explosion. I think that higher octane does clean your engine, because less carbon deposits means less carbon build up right!

Yeah, i thought the same thing. Except for the person that says it doesnt clean anything would be right. Because lessening carbon buildup isn't actually cleaning anything, its just preventing as much further buildup than you would have in a lower octane gas. Then again, I may be wrong and youre right, I don't have any proof, its just what ive always thought/heard. So, with that said what do the AF gods have to say?

High octane fuel kicks ass...

bluevette- it's not a slower burn rate per-se, it's a higher resistance to ignition, thus preventing self-ignition when it is squeezed more in a higher compression engine. also, since higher octane is further refined etc... as i said in my last post, it prevents more carbon builup. you need a carb/injector cleaner to remove certain deposits (varnish etc...) in the fuel system.

If you want to consider the prevention of carbon build up in the egine a way of keeping it clean then higher octane would do that. But it does not remove any deposits that all ready exist. That is what those addatives are for that they put in some of the gasoline brands.

If there's too much carbon buildup in your injectors even the additives wont work... then you have to take them out and clean them.

I would NOT suggest that a person use the following fuel mixtures without considering the detrimental effects on your engine, vital engine components (O2 sensor, etc), and other potential damage. That said, the information is interesting.
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Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.

Formula #2 - Xylene
R+M/2.........117
Cost...........$2.75/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.

Formula #3 - Methyl-tertiary-butyl-ether (MTBE)
R+M/2.........118
Cost...........$3.50/gal
Mixtures with 92 Octane Premium
10%...........94.6 Octane
20%...........97.2 Octane
30%...........99.8 Octane
Notes: Oxygenate. Very common in octane booster products. Has lower BTU content than toluene or xylene, but oxygenate effect makes the gasoline burn better and produce more energy.

Formula #4 - Methanol or Ethanol
R+M/2.........101
Cost...........$0.60 - $1.75/gal
Mixtures with 92 Octane Premium
10%...........94.3 Octane (Methanol)
10%...........94.7 Octane (Ethanol)
20%...........Not Recommended
Notes: Methanol is wood alcohol. Ethanol is grain alcohol and found in Gasohol in 10% ratios. Both alcohols are mildly corrosive and will eat gas tank linings, rubber and aluminum if used in excessive ratios. Main ingredient in "Gas Dryers", combine with water.

Formula #5 - Isopropyl Alcohol and Tertiary Butyl Alcohol
R+M/2.........101
Cost...........$0.60-$1.50/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........Not Recommended
30%...........Not Recommended

Notes: Similar to Methanol/Ethanol. Isopropyl Alcohol is simply rubbing alcohol.

Sample Mixture
To make your own octane booster, it is easiest to make up a large batch, and then bottle it up in "dosage-size" uses.
Below is the basic formula of one of the popular octane booster products. To make eight 16 ounce bottles (128 oz = 1 gal):

100 oz of toluene for octane boost
25 oz of mineral spirits (cleaning agent)
3 oz of transmission fluid (lubricating agent)
This product is advertised as "octane booster with cleaning agent *and* lubricating agent!". Diesel fuel or kerosene can be substituted for mineral spirits and light turbine oil can be substituted for transmission fluid. Color can be added with petroleum dyes.


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Diesel? What the hell... :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes:

That's more like a recipe to total your gas engine within a few minutes of running!

Yeah man i don't doubt you, but that scares the hell out of me!

Looks like a meth lab than a gasoline mixture. J/K

Isn't it possible to simply purchase pure octane. I mean, "octane" is simply a liquid alkane that contains 8 carbons per molecule. Also I was under the impression that the breaking of carbon bonds within the octane molecules that actually released their potential energy as heat; hence giving petrolium it's property of cumbustability.