DiscreetSpeed
Member
- :
- 03 MSP
i dont understand what your askin bud, what does it do, you mean?Metal MP5 said:
Home Brewed Race Fuel (or higher octane)
- Thread starter DiscreetSpeed
- Start date
Im saying that what i read was that octane rating means the % of octane a fuel contains
87octane = 87% octane and 13% heptane (which is crap that doesnt compress well).
Now i understand that you can't have more octane than fuel itself, so if this is true ... your fuel can't have more than 100 octane which would mean it is made with 100% octane.
so what exactly does 103 octane fuel means ? Since howstuffworks.com says (like i just said) that octane rating = % of octane in your fuel mixture ... it can't be 103%
So i am asking, since i dont think something can be more pure than 100%, what is or what does 103 octane fuel do ?
I know it's not clear ... its late and my brain went to sleep a while ago =) Anything you can tell me about fuel with more than 100 octane would be helpful.
Here's a sample of what howstuffworks.com says:
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The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.
It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.
****************************************
I hope it'll help you understand why im confused =)
The full article is here: http://auto.howstuffworks.com/question90.htm
87octane = 87% octane and 13% heptane (which is crap that doesnt compress well).
Now i understand that you can't have more octane than fuel itself, so if this is true ... your fuel can't have more than 100 octane which would mean it is made with 100% octane.
so what exactly does 103 octane fuel means ? Since howstuffworks.com says (like i just said) that octane rating = % of octane in your fuel mixture ... it can't be 103%
So i am asking, since i dont think something can be more pure than 100%, what is or what does 103 octane fuel do ?
I know it's not clear ... its late and my brain went to sleep a while ago =) Anything you can tell me about fuel with more than 100 octane would be helpful.
Here's a sample of what howstuffworks.com says:
****************************************
The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.
It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.
****************************************
I hope it'll help you understand why im confused =)
The full article is here: http://auto.howstuffworks.com/question90.htm
p5sundevil
Member
- :
- 03.5 MidnightBlue p5
probably relates to the chemical term supersaturated....it techincally could have more than 100% of a particular compound.
But I also think that the two explanations of it being a direct % of the fuel is a little simplified.
But I also think that the two explanations of it being a direct % of the fuel is a little simplified.
Installshield 2
Gothenburg Superiority
alright dudes...The "octane" number you see on a gas pump, be it 87, 89, 93 or whatever, is simply an averaged comparison to that of a different mixture of hydrocarbons...It actually has very little to do with the actual octane content of the gasoline...
Octane numbers are basically given as a comparison to a pure mixture of Isoctane, and heptane (this IS NOT gasoline)...Isoctane (2,2,4-Trimethyl Pentane...I am such a dork) is very stable, and reacts to compression very linearly (in terms of handling the compression before ignition, as well as expanding uniformly once ingnited)...Heptane would probably blow the s*** out of you if you squeezed it in your hand...and thus: Isoctane recieves a octane "rating" of 100, and heptane gets a 0...
the number you see on the pump relates the gasolines "behaviour" to that of a mixture of Isoctane and heptane (87 gasoline behaves like a mixture of 87% Isoctane, and 13% heptane...but that DOESN'T mean it is Isoctane and Heptane...gasoline is a much more complicated mixture)...
Now also you will notice most of the time something like (R+M)/2 near the pump...this is an average created by the two octane rating procedures...RON or Research Octane Number tests an engine at 600 rpm or something, and MON or Motor Octane Number is tested at 900rpm at higher load, I don't remember...but in either case the numbers don't always match...so the two are added together and divided by 2 to effectively create and average octane rating...So a gas with a RON of 92 and a MON of 90, gives you an overall averaged rating of 91...
When you run into numbers north of 100, you are simply using fuels that are that much more stable than pure Isoctane...and I don't know how they rate those types of fuel...
Octane numbers are basically given as a comparison to a pure mixture of Isoctane, and heptane (this IS NOT gasoline)...Isoctane (2,2,4-Trimethyl Pentane...I am such a dork) is very stable, and reacts to compression very linearly (in terms of handling the compression before ignition, as well as expanding uniformly once ingnited)...Heptane would probably blow the s*** out of you if you squeezed it in your hand...and thus: Isoctane recieves a octane "rating" of 100, and heptane gets a 0...
the number you see on the pump relates the gasolines "behaviour" to that of a mixture of Isoctane and heptane (87 gasoline behaves like a mixture of 87% Isoctane, and 13% heptane...but that DOESN'T mean it is Isoctane and Heptane...gasoline is a much more complicated mixture)...
Now also you will notice most of the time something like (R+M)/2 near the pump...this is an average created by the two octane rating procedures...RON or Research Octane Number tests an engine at 600 rpm or something, and MON or Motor Octane Number is tested at 900rpm at higher load, I don't remember...but in either case the numbers don't always match...so the two are added together and divided by 2 to effectively create and average octane rating...So a gas with a RON of 92 and a MON of 90, gives you an overall averaged rating of 91...
When you run into numbers north of 100, you are simply using fuels that are that much more stable than pure Isoctane...and I don't know how they rate those types of fuel...
Last edited:
BlueWolfCry
Member
- :
- 02 LX, 03 MSP
interesting....but expensive. how much does typical racing fuel cost?
DiscreetSpeed
Member
- :
- 03 MSP
104 runs 5 bucks a gallon here in houston.
c10 runs 6 bucks and c116 runs 8 bucks.
c10 runs 6 bucks and c116 runs 8 bucks.
Cellerator
Member
- :
- 2012 Mazda 3i Skyactiv Hatchback
mods, plz make this a sticky since it will b good for all of us that love 2 race
DiscreetSpeed
Member
- :
- 03 MSP
use my chart on page one bud...id say nothin less than 93...jflo said:
you mix 2 gals of 100 into 5 gallons of 91 and it equals out to 93.5
add another 2 gals of 100 and it gives you 95.
Installshield 2
Gothenburg Superiority
haha, no way dude...Mechanical engineering...we did some of that octane crap in a chem class though, I have no idea how I remember any of it...It may not be though, so if someone sees holes in it let me know...MSPinVA said:
umm, sorry i didn't get back to you earlier about that, but it's 4.999/gallon for 100 octane @ 76. i just bought 8 gallons today for 40 bucks...set the boost controller to 12 psi, well i'm getting the spike up to 12 psi then it drops down to 10. what do you guys think how much higher could i go ? i filled up 8 gallons of 100 octane when the low fuel light was on
The issue with higher octane fuels is that unspent fuel exiting through your exhaust system shortens the life of your catalytic converters. To some degree, a higher octane fuel can provide a more even burn, and actually reduce emissions. But above a certain octane rating, you may not be burning all the fuel in the cylinder during the ignition stroke. The unspent fuel is pushed out with the other combustion by-products during the exhaust stroke, and right into the cats.jflo said:
This is where a wideband O2 Sensor comes in handy. You can monitor your A/f mixture.
Installshield 2
Gothenburg Superiority
Very good point...
Think about what an octane rating refers to...It displays the similarity of your fuel, to a very stable mixture...Think of the octane as a non-polar "water" like substance that handles compression (Water is polar, so it never mixes with gasoline (looks like Italian dressing)...and water does not like compression in the slightest...but nevermind that for this)...Only think of it as water in that it does nothing for the reaction itself, other than stabalizes it and buffers it...overall keeping reaction temps down, and significantly slowing the rate of expansion...But when you get too much, especially when the application is not caling for it...it will not allow the reaction to happen quickly enough, or hot enough...and hurt power, your air, and your catalysts...
Think about what an octane rating refers to...It displays the similarity of your fuel, to a very stable mixture...Think of the octane as a non-polar "water" like substance that handles compression (Water is polar, so it never mixes with gasoline (looks like Italian dressing)...and water does not like compression in the slightest...but nevermind that for this)...Only think of it as water in that it does nothing for the reaction itself, other than stabalizes it and buffers it...overall keeping reaction temps down, and significantly slowing the rate of expansion...But when you get too much, especially when the application is not caling for it...it will not allow the reaction to happen quickly enough, or hot enough...and hurt power, your air, and your catalysts...
xxgosumastaxx
Member
- :
- Mazda, Protege 5
Saftey first
is it safe to make your own fuel???
is it safe to make your own fuel???
Installshield 2
Gothenburg Superiority
uh...yeah somewhat...as long as you are not carrying around a flamethrower, or having a cigarette....
