100 octane KA

[McRussellPants]

Originally Posted by Brian

Yeah, looks like I won't be using it.

I have no desire to change things around. Putting gas into the gas tank is the most amount of work I want to do.

And, seeing as I have a stock engine, I don't want to LOSE ANY power.

Thanks guys.

Put in Racegas
advance timing all the way
?????
profit

[sillyvia13]

Originally Posted by McRussellPants

Put in Racegas
advance timing all the way
?????
profit

SOUNDS LIKE A PLAN!!!!!

BRAIN I AM SEND A FUCKING ECU! to you...
gimmie your address NOW!

If you like it send me your ecu and $50!
You gotta see the power from these...
pm me well talk... you need more than that na ka oem ecu can do...
hit me

[Def]

This thread is full of fail.


Combustion rate is NOT directly related to octane rating of a fuel. There is some race gas that has a faster combustion rate than normal pump gas, and some that has a slower combustion rate of the gas. VP Import stuff in particular touts its higher combustion rate to enable a small increase in power at very high RPM(<8000 RPM).

[racepar1]

Originally Posted by s0apgun

so you're saying

if i put 93 octane in my stock ka i'm actually losing power..

so putting 87 in my tank is actually better

some one hit me with some knowledge

Ka's are supposed to run on 91 octane, that is what you should run. I get a bit of pinging in hot weather from 87 octane, so I stick with 91. I doubt you will lose anything with 93 octane, but with 110 octane you probably will.

Originally Posted by Def

This thread is full of fail.


Combustion rate is NOT directly related to octane rating of a fuel. There is some race gas that has a faster combustion rate than normal pump gas, and some that has a slower combustion rate of the gas. VP Import stuff in particular touts its higher combustion rate to enable a small increase in power at very high RPM(<8000 RPM).

In all cases, no. Generally speaking though higher octane means slower combustion. You can get race gas that will burn as fast or faster then pump gas, but most race fuels don't. What higher octane really means is a higher resistance to combustion. It takes higher cylinder pressures and/or temperatures to burn higher octane fuels efficiently then it does to burn pump gas efficiently.

[Def]

Originally Posted by racepar1

In all cases, no. Generally speaking though higher octane means slower combustion. You can get race gas that will burn as fast or faster then pump gas, but most race fuels don't. What higher octane really means is a higher resistance to combustion. It takes higher cylinder pressures and/or temperatures to burn higher octane fuels efficiently then it does to burn pump gas efficiently.

Absolutely 100% incorrect on all counts. Burn kinetics at the same octane rating, but with a fuel made of up different compounds(more aromatics, more TEL, etc.), will be vastly different.

Tuning cars on different fuels, and learning a few things about combustion engineer makes this readily apparent.

[racepar1]

Originally Posted by Def

Absolutely 100% incorrect on all counts. Burn kinetics at the same octane rating, but with a fuel made of up different compounds(more aromatics, more TEL, etc.), will be vastly different.

Tuning cars on different fuels, and learning a few things about combustion engineer makes this readily apparent.

Ok then what does octane signify mr fuel expert? A higher octane fuel has a higher resistance to combustion. Without a higher resistance to combustion it would pre-detonate in high compression/boost applications just like street gas would. Since a higher octane fuel has a higher resistance to combustion it will not burn as efficiently in a low compression/boost application, because it NEEDS the extra cylinder temps/pressure, which will cost you some power. That is logic, I do not need an engineering degree to tell me that that statement is correct. You are right that the burn kinetics will certainly differ with the different compositions of different fuels at least, but I did agree with that statement already in my previous post.

[kapowerhicomp1]

Originally Posted by racepar1

Ok then what does octane signify mr fuel expert? A higher octane fuel has a higher resistance to combustion. Without a higher resistance to combustion it would pre-detonate in high compression/boost applications just like street gas would. Since a higher octane fuel has a higher resistance to combustion it will not burn as efficiently in a low compression/boost application, because it NEEDS the extra cylinder temps/pressure, which will cost you some power. That is logic, I do not need an engineering degree to tell me that that statement is correct. You are right that the burn kinetics will certainly differ with the different compositions of different fuels at least, but I did agree with that statement already in my previous post.

are you coming to htm sun????

[Def]

Originally Posted by racepar1

Ok then what does octane signify mr fuel expert? A higher octane fuel has a higher resistance to combustion. Without a higher resistance to combustion it would pre-detonate in high compression/boost applications just like street gas would. Since a higher octane fuel has a higher resistance to combustion it will not burn as efficiently in a low compression/boost application, because it NEEDS the extra cylinder temps/pressure, which will cost you some power. That is logic, I do not need an engineering degree to tell me that that statement is correct. You are right that the burn kinetics will certainly differ with the different compositions of different fuels at least, but I did agree with that statement already in my previous post.

It's right in the wikipedia article - it's resistance to detonation - which is NOT combustion.

Fuel with a higher octane doesn't "soak up" extra combustion energy as it's burning - it RELEASES energy as long as there is enough heat/pressure to make it undergo the exothermic combustion process. A chemical "reluctance" to undergo combustion does not equal a greater energy input to start the combustion process, even though it might take higher pressures/temperatures to get the internal energy of the mixture high enough to spontaneous combust. You're thinking about this in a mechanical way of "more energy required to combust = higher octane," when it's a really a chemical change that makes it reluctant to undergo detonation due to high pressure.


...and no reason to get pissy due to the fact that I took quite a few classes in undergrad directly related to this subject.