100 octane KA

[lflkajfj12123]

yeaaaaaahhhh

my brain just got fucked in the ass

[sillyvia13]

vp racefuels.com
i ran it in my na ka s13 dohc with a touch of timing, IT LOVED IT!

not something i did often, but it enjoyed it...
btw brain you got a s14 huh?
if so no go on ecu, you'd need a s13 / s14 jumper harness and a s13 ecu, probably like $150 in the end, but you can tune like its a obd0

[BoostedCoupe]

Originally Posted by sillyvia13

vp racefuels.com
i ran it in my na ka s13 dohc with a touch of timing, IT LOVED IT!

not something i did often, but it enjoyed it...
btw brain you got a s14 huh?
if so no go on ecu, you'd need a s13 / s14 jumper harness and a s13 ecu, probably like $150 in the end, but you can tune like its a obd0

He has a s13 now. The s14 was sold.

[Icy13]

Um, to the squabble over what octane means: Octane rating - Wikipedia, the free encyclopedia

Translation from a person with a Physics Degree (me): The point of an internal combustion engine is to combust fuel to release energy, doing work over a certain time (aka power = work/time). Thus more power with more energy or less time.

If the fuel has a higher resistance to combustion, than you will take more time to combust. Thus the power out put is lower assuming that you have released the same amount of energy from the fuel (assuming basically that a higher octane fuel is simply a lower octane fuel with octane raising additives, which is generally the case).

Damage: probably not, but the comments about deposits remaining I can get on board with as the likelihood of complete combustion within the same amount of time as lower octane fuel is pretty slim.

However, octane is a rating of resistance to detonation not combustion, although the two are related. Detonation, in car terms, means that the fuel has combusted due to heat and pressure premature to the desired instant of ignition. In general terms, detonation is uncontrolled combustion that occurs supersonically (the flame front travels faster than sound)

Combustion, in automotive terms, refers to the planned burning of fuel ignited, in a gasoline engine, by a spark plug. This usage of combustion refers to the deflagration form of combustion, basically a sub-sonic flame front

What all this means scientifically to the layman (most of us): Although octane measures resistance to "detonation", the same proporties that cause resistance to this inhibit "combustion." Thus, a flame front will travel slower in a higher octane fuel than a lower octane one. Thus, one has to time their engine to ignite fuel earlier for a higher octane fuel to achieve complete combustion at the same point in time as a lower octane fuel.

-------------------------------------------------

BOTTOM LINE: I do encourage you to read through all the above, quite educational and good for all car enthusiats and I enjoyed writing it. However this basically means that in an unmodified engine, use the lowest octane fuel that the engine was designed for (for my s14, there is a little sticker on the filler door that says use 92 octane aka Premium) for best performance and engine health. Lower octane risks detonation, higher octane lowers power output and risks deposits in the cyclnders, although this is prolonged use, in the short term you would be fine as the deposits would be washed by the detergents in all modern gas.

Bottom Bottom Line: if you want the smell, try to find an additive that simulates it or mix 87 octane and race gas (find out the octane) to achieve the ideal 92 octane your engine craves (anyone seen Idiocracy? 92 Octane, it's what kas crave!!! :-P)

Konrad

Edit: I forgot to insult people :-P (seriously, though, dont take this that way, I mean it to help others not insult you def)

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).

"Combustion" rate is indeed indirectly related to octane rating (combustion in automotive terms, in scientific terms detonation is a type of combustion and therefore octane is directly related). My thoughts on the fuel that burns faster is that there must be some sort of catelyst that causes the heat to spike when ignited that is inert during the compression stage of the Otto cycle. Cool shit there, if I am correct, but this is an exception not the rule.

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 engineering makes this readily apparent.

Not entirely true, octane rating is not separate of composition, it simply compares detonation point versus a standard. That being said, different additives may catalyze the reaction creating these differences. I am not an expert in different gas types, this is simply an analysis based on physics/chem/thermo

[Def]

Originally Posted by Icy13

Um, to the squabble over what octane means: Octane rating - Wikipedia, the free encyclopedia

Translation from a person with a Physics Degree (me): The point of an internal combustion engine is to combust fuel to release energy, doing work over a certain time (aka power = work/time). Thus more power with more energy or less time.

A translation from someone with a mechanical engineering degree (me) and an academic background in the engineering behind internal combustion engines: Physicists don't learn about this subject matter in depth in their degree program, so that's why you'd never hire a physicist to be a combustion/ICE engineer.

If the fuel has a higher resistance to combustion, than you will take more time to combust. Thus the power out put is lower assuming that you have released the same amount of energy from the fuel (assuming basically that a higher octane fuel is simply a lower octane fuel with octane raising additives, which is generally the case).

I have no idea why you think this, but it's wrong. An Otto cycle engine(a spark ignition 4 stroke) will have a "very rapid" pressure spike after ignition, which is happening BTDC. You want peak pressure somewhere around 15-30 degrees ATDC depending on the engine and the operating parameters. I have no idea how you think a fuel being resistant to detonation makes it resistant to combustion. This is not the same process. Resistance to detonation is what octane rating refers to - I suggest you actually READ the wikipedia article you linked instead of making up definitions for terms. There is no "energy absorbed" by the fuel molecule during combustion, the heat/pressure from the combustion just overcomes the reaction energy needed for the combustion to spread to the rest of the air fuel mixture.

"Combustion" rate is indeed indirectly related to octane rating (combustion in automotive terms, in scientific terms detonation is a type of combustion and therefore octane is directly related). My thoughts on the fuel that burns faster is that there must be some sort of catelyst that causes the heat to spike when ignited that is inert during the compression stage of the Otto cycle. Cool shit there, if I am correct, but this is an exception not the rule.

Sorry, that Candy Land story about "magic catalysts" causing heat spikes is not true, so it is not "cool shit." Where are you getting this crap?

Not entirely true, octane rating is not separate of composition, it simply compares detonation point versus a standard. That being said, different additives may catalyze the reaction creating these differences. I am not an expert in different gas types, this is simply an analysis based on physics/chem/thermo

???

Octane rating is indeed entirely independent from composition. There are a million ways to get a fuel with an AKI of 100, and they can have wildly varying properties.


VP knows way more about fuels than ANYBODY here, so you might want to question your "knowledge" about why they formulate fuels for different applications which include wide variations in RPM windows where the fuels are meant to perform best.



This thread is beyond :facepalm status. Contact VP Race Fuels if you don't believe me and ask them if octane rating is directly related to burn rate. They'll probably tell you to learn to read and look at their product line which CLEARLY spells out that this isn't the case.

[kapowerhicomp1]

91 octane its great for stock ka with minor or major mods running with stock compression .........my ka has jim wolf ecu...with 93 and 100 octane tune... if going to run high compression or turbo with high boost 100+ is the best......

[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????

[racepar1]

Originally Posted by kapowerhicomp1

are you coming to htm sun????

I wish, too broke.

[kapowerhicomp1]

next year bro.... but i will have video and pics after the event ... on htm kapower out....................

[kapowerhicomp1]

Originally Posted by racepar1

I wish, too broke.

when can you do air ducts for brakes...

[Icy13]

I heartily support the thread jack ^^

But, to def, please pm if you want to continue this but I have not idea what you are referring to when you say detonation and combustion are not related. Having taken both our advice and read wikipedia, they are indeed closely related. I am not going to post the links.

My explanation was meant for the layman as I wrote, and no I am not trying to re-engineer the internal combustion engine. However, engineering is not some sort of magical exception to science and thus I was providing a basic explanation of octane rating and how that affects combustion based on my analytical ability and knowledge from Wikipedia.

2. I fully admit that the "candy land shit" may be just that. I was taking a wild guess. I actually would appreciate information you may have on that, it would be quite interesting.

3. What I meant to say is that composition is not taken into account when judging octane. I know that two diff substances can have the same octane. I think I made that unclear and for that I apologize.

4. I guess there could be a loophole i am missing in the science where a fuel with a high resistance to pressure based ignition (which is the basis of detonation, a pressure wave compresses the fuel and causes it to combust) and a low heat requirement, but my understanding of such matters is that one cannot seperate pressure and temperature dependance. I may be mistaken, and if so, I appologize for my candy land shit once again. CTFD mr. def.

Also, sorry I cant spell

And if i misused the word catalyst in some way, I am truly remorseful, I merely meant to say that there may be more factors outside of typical ideal combustion that will affect the process, perhaps significantly.

I dont know what htm sun is (*sadface ) Oh well....

[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.

[Brian]

So, I see paragraphs...

LOCKED NOW.

Thanks for the those with simple answers.

kisses,
bh