2.0 NA gas spec

[David Harper]

https://www.cenex.com/about/cenex-i.../what-octane-ratings-really-mean-for-your-car

"An octane rating is simply a measure of how heat resistant a fuel is in order to prevent knocking. In other words, octane doesn’t enhance combustion — it prevents the air-fuel mixture inside an engine from igniting before it’s supposed to.

The higher a fuel’s octane, the more resistant it is to knocking. If you hear knocking, you could be using the wrong octane for your ride. The recommended octane rating varies by vehicle, so always consult your owner’s manual to determine which is right for you. Some vehicles require a higher octane rating because they have what’s known as supercharged or turbocharged engines that create higher compression levels."

https://www.eia.gov/energyexplained/gasoline/octane-in-depth.php

"Octane ratings are measures of fuel stability. These ratings are based on the pressure at which a fuel will spontaneously combust (auto-ignite) in a testing engine"

A simple google search would tell you what the differences actually are instead of what you just "believe" to be true (I believe that the way premium allows for higher potential maximum cylinder pressure is by delaying ,in effect, combustion")
[/QUOTE]
If octane makes the fuel more "heat resistant" as you stated, then that IS, IN FACT, delaying combustion. Are you not intelligent enough to get this?

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[dark_knight097]

https://www.cenex.com/about/cenex-i.../what-octane-ratings-really-mean-for-your-car

"An octane rating is simply a measure of how heat resistant a fuel is in order to prevent knocking. In other words, octane doesn’t enhance combustion — it prevents the air-fuel mixture inside an engine from igniting before it’s supposed to.

The higher a fuel’s octane, the more resistant it is to knocking. If you hear knocking, you could be using the wrong octane for your ride. The recommended octane rating varies by vehicle, so always consult your owner’s manual to determine which is right for you. Some vehicles require a higher octane rating because they have what’s known as supercharged or turbocharged engines that create higher compression levels."

https://www.eia.gov/energyexplained/gasoline/octane-in-depth.php

"Octane ratings are measures of fuel stability. These ratings are based on the pressure at which a fuel will spontaneously combust (auto-ignite) in a testing engine"

A simple google search would tell you what the differences actually are instead of what you just "believe" to be true (I believe that the way premium allows for higher potential maximum cylinder pressure is by delaying ,in effect, combustion")

If octane makes the fuel more "heat resistant" as you stated, then that IS, IN FACT, delaying combustion. Are you not intelligent enough to get this?
[/QUOTE]
Dude, its not hard to understand. I bet you didn't even read the damn links.
More heat resistant as in if there are higher cylinder temps the fuel can resist that extra heat so that it combusts exactly when ITS SUPPOSED TO. Not before and not after.

If the fuel is not stable enough in those higher heat conditions to make it to the point its supposed to ignite, that is PRE-IGITION. If the fuel ignites at the moment its supposed to, that means it is right on time not "delayed". Any combustion after the point of intended ignition is DETONATION.

You need to look up what delay means. Is english not your first language?

 

[ulieq]

no way high octane helps tried it million times.

 

[2020k20c2sport]

From what I know about octane. The best mileage you can get will be with whatever the car requires. So I use 87 with mine on the factory tune. Will obviously use 91 after ktuner because its turned for it. As far as E free fuel goes I haven't been able to find a pump that sells ot that's on my way to anywhere. My 18 civic got a lot of E free gas though and I do feel like it was easier to keep the mpgs up. It was also a cvt as well so idk.

 

[David Harper]

If octane makes the fuel more "heat resistant" as you stated, then that IS, IN FACT, delaying combustion. Are you not intelligent enough to get this?

Dude, its not hard to understand. I bet you didn't even read the damn links.
More heat resistant as in if there are higher cylinder temps the fuel can resist that extra heat so that it combusts exactly when ITS SUPPOSED TO. Not before and not after.

If the fuel is not stable enough in those higher heat conditions to make it to the point its supposed to ignite, that is PRE-IGITION. If the fuel ignites at the moment its supposed to, that means it is right on time not "delayed". Any combustion after the point of intended ignition is DETONATION.

You need to look up what delay means. Is english not your first language?
[/QUOTE]
One more time; If the fuel does not ignite before it's "supposed to" then combustion has been delayed until it's "supposed to" happen. You don't know what you're talking about.
https://www.researchgate.net/public...es_measured_in_an_ignition_quality_tester_IQT

https://www.sciencedirect.com/science/article/abs/pii/S0010218006002203

perhaps you may not want to post here anymore.

 

[Gruber]

Without some chemistry background, you are not likely to truly understand octane rating. But reading helps understand it on a sufficient practical level.

Octane rating is closely related to what's called "the activation energy" of a (combustion) reaction. High octane number correlates with high activation energy. It means a significant "impulse" is needed to initiate the reaction. It's not the same as the degree of combustibility, ignitability, flammability, volatility or the energy of the reaction. The activation anergy directly affects the kinetics (or rate or speed) of chemical reactions. High activation energy means the reaction will be harder to initiate and then it will proceed at a slower rate.

It's (only) somewhat similar to the "brisance" (or crushing power) of explosives. High brisance is like low octane number:

Wikipedia: "The value of brisance depends on the application. At one extreme, if an explosive is to be used for propulsion, e.g. by driving a piston or a bullet, brisance is likely to be undesirable, because the objective will be to move the load, not to shatter it or the engine or firearm, nor to produce a loud report. Such propulsive charges are designed to burn controllably, such as carburetted fuel/air mixes in vehicle piston engines, or nitrocellulose fibres or grains of controlled textures in firearm cartridges."

For example, a mixture of hydrogen and oxygen is by no means safe, and the energy of the reaction is rather huge. But it can sit in a closed vessel for years and not explode even if heated and compressed. Then when it explodes it's not a "powerful explosive" compared to other explosives, because it will burn relatively slowly (not delayed, but slower speed of the front) so it will not produce a hard, crushing hit (knock). Well, hydrogen has a very high octane number.

Finally, people often think about gas mileage when talking about octane. Now this is completely wrong, because gas mileage may vary with octane only in a random and insignificant way, depending on the particular fuel and particular car. There is no general relationship between octane and gas mileage until the engine stops working as designed because of extremely low or extremely high (racing fuel) octane.

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