do you use 87 octane in your honda ex civic.

FC3L15B7

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I made the mistake of putting 89 instead of 87 into mine...

It made a $10 difference, never again lol.
Lol. Yeah, in that case, if you've been running 87 and at half a tank you fill up with 89 once, you're essentially using 88 for that tank until you use up gas and put in more 87, so there's not really that much of a difference - except that $10 you were going to use for lunch. ;)
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Man, I thought only Californians and maybe Hawaiians got screwed on gas prices, .50+ cents a gallon difference would probably make me think twice on tuning a civic to where you'd need premium, but price difference between premium and regular at my local stations range from 20-30 cents, so total price difference on an average tank of gas is $2-$3. Since I run a tune, I use the premium, if for no other reason because knock control will never go above .54 on premium, while with regular I've seen it go as high as .9.
 

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Man, I thought only Californians and maybe Hawaiians got screwed on gas prices, .50+ cents a gallon difference would probably make me think twice on tuning a civic to where you'd need premium, but price difference between premium and regular at my local stations range from 20-30 cents, so total price difference on an average tank of gas is $2-$3. Since I run a tune, I use the premium, if for no other reason because knock control will never go above .54 on premium, while with regular I've seen it go as high as .9.
I pay .20 or more cents per LITRE for Premium than Regular. I wish the difference for me was only .50 cents per gallon. That's like .76 cents per litre gallon.
 
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I pay .20 or more cents per LITRE for Premium than Regular. I wish the difference for me was only .50 cents per gallon. That's like .76 cents per litre.
I think you meant per gallon. :cool:
 

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I think you meant per gallon. :cool:
What did I calculate? LOL.

EDIT:
.50 cents per gallon would be .13 cents per litre.
I pay at least .20 per litre more, which is .76 cents per gallon

hahaha. Doh!
 
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saz468

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As I posted before I use 93 octane yes it’s a few cents more than 87. I’ve always been using higher octane for years. Plus the mileage I get with the civic I fill up every two weeks
 

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As I posted before I use 93 octane yes it’s a few cents more than 87. I’ve always been using higher octane for years. Plus the mileage I get with the civic I fill up every two weeks
I wish it was only a few cents more here in Maryland. These are todays prices at the Sunoco station I use (87,89,91):

Honda Civic 10th gen do you use 87 octane  in your honda ex civic. IMG_20200127_091400


It's not listed on the Gasbuddy app but I use the Ultra 93 (I'm tuned for it) and the difference for that is 60 cents over regular.
 

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I wish it was only a few cents more here in Maryland. These are todays prices at the Sunoco station I use (87,89,91):

IMG_20200127_091400.jpg


It's not listed on the Gasbuddy app but I use the Ultra 93 (I'm tuned for it) and the difference for that is 60 cents over regular.
Regular is 2.49 in my area of Florida. Believe it or not some stations mostly circle k ( shell) only have 89 & 93
Octane they don’t offer 87 and some stations a very few and far between offer 87 only. But this is snowbird season in Florida so everything go’s up ( prices)
 

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I ran regular about half of the time. Premium about half of the time when the price would drop for a day or two.

I have a KTuner now so I always run premium.

I look at it like this, it doesn't hurt to run premium instead of regular and a lot of the gas stations around me handle the premium gas a little better (water was found mixed in with the regular gas a few times.. I avoid those gas stations now). In my other cars made a much bigger difference than my civic. Before my tune, I noticed that it felt a little different. A veerrry small bit stronger at low rpm and probably weaker up top. MPG was within 1 mpg better when I was driving around town and no better or worse on the highway so not a big enough difference to write home about. To those saying it's a waste of money, why do you buy nice wine or beer vs the cheap stuff if they both get you drunk? Because you want to and it's not hurting anyone. It might be a waste but it might not. Maybe it'll pay off in 20 years but who tf knows LOL
 

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I didn't say higher octane gasoline was more volatile, but octane has everything to do with volatility.




The presence of spark does not guarantee ignition. The voltage - or energy of that spark - has to meet the minimum ignition energy or MIE. I suppose you're about to get a lesson in ignition systems and spark plugs.

An engine designed for lower octane, higher volatility gasoline may have spark plugs with narrow spark plug gaps because that's the gap that is most efficient for that engine. Those narrow gaps need less voltage than a spark jumping a larger gap, which you typically would have in higher-performance engines using premium gas. In a "premium engine", you need a higher energy charge to get the spark to jump a larger gap and its voltage is high enough for MIE when using higher octane gasoline to not just ignite the fuel, but burn it as completely as possible while resisting preignition. The more complete the burn, the higher the power output, higher fuel mileage, lower emissions, less NOx for your catalytic converter and less money. Further to the point, if the engine is designed to use lower octane, that is the grade that should have the most complete combustion (aka higher the power output, higher fuel mileage, lower emissions, less NOx). Using higher octane gas when it's not applicable can have the opposite effect.

For example: If you compare 87 octane and 91 octane gasolines in an engine that is supposed to be using a lower octane and has narrow spark plug gaps because that's its most efficient gap for that engine design and appropriate grade of fuel you may not get ignition or can have incomplete combustion from the higher octane, lower volatility gasoline when it's cold. In addition to the likelihood of lower voltage sparks across a narrow plug gap, the gasoline doesn't evaporate as quickly in the cold, exacerbating the issue.



When it's hot, it's not likely to affect it because even the higher octane fuel is evaporating quickly and the combination of heat and compression is pushing the limits of autoignition you're so fond of you had to use bold type.

Preignition is a type of autoignition like thumbs are fingers but fingers are not thumbs. Preignition is the lowest temperature of ignition without an external ignition source or flame before ignition is supposed to occur and Autoignition is the lowest temperature of ignition without an external ignition source or flame at the time ignition is supposed to occur. Preignition is what high octane, lower volatility gasoline resists. Preignition is due to higher heat levels, which is why you may get engine knock in the summer while using the recommended fuel grade and can go up in fuel grades to resist preignition and reduce engine knock. Autoignition is what you get from compressing diesel fuel and doesn't belong here because we're talking about gasoline internal combustion engines that have external ignition source, even though some diesels do. It doesn't matter here. I hope you've learned something.
You gave a long speech, but the length of your homegrown philosophies doesn't make them right, even if it was a 23 hour speech.

Octane and volatility are two separate, unrelated properties, and you have zero chance of understanding it without a degree in chemistry. You just need to accept it.

There are compounds that are very volatile that have also high octane rating (methane, propane, butane) and there are compounds that are less volatile than gasoline that also have very high octane ratings (anything highly branched, alcohols, many other heavier compounds).

There are also compounds with very low octane rating that can be either more volatile or less volatile than gasoline.

Gasoline is a mixture. It's composition is tuned for the desired combination of volatility and octane for compliance with regulations.

High octane fuel is not less volatile, because the volatility of fuel is strictly controlled for location and season (winter and summer).

Spark ignition is not affected by octane, only by the volatility and flammability limits. Are you getting misfire codes on high octane? :rofl:
 


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have zero chance of understanding it without a degree in chemistry.
I don't have a degree in chemistry and I understand how octane and volatility work. :topic:

Why does everyone have to have the same argument in every one of these threads lol. I think that gtman is right that we need a sticky or a forum category that teaches people about fuel types and lets them ask questions.
 

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I don't have a degree in chemistry and I understand how octane and volatility work. :topic:
Without a degree in chemistry you can only pick who you want to believe and repeat what yo've read.:yes:

Explain with your hands behind your back why addition of 10% ethanol to gasoline increases its vapor pressure, but addition of 60% ethanol decreases vapor pressure over the mixture. And then explain why it's different with butanol. You can ask a friend who used to haul gas. Good luck.:D
 

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Without a degree in chemistry you can only pick who you want to believe and repeat what yo've read.:yes:

Explain with your hands behind your back why addition of 10% ethanol to gasoline increases its vapor pressure, but addition of 60% ethanol decreases vapor pressure over the mixture. And then explain why it's different with butanol. You can ask a friend who used to haul gas. Good luck.:D
It's not that hard to figure this stuff out man. I get it if you are proud of your education but projecting it on other people to try to make them feel stupid is not cool.

If you explain it then people will understand. If they don't understand then you probably did a bad job at explaining it.

It has something to do with the attraction of Ethanol molecules since they have Hydrogen bonds. If there is enough gasoline in the way then it blocks the ethanol from attracting. If the ethanol is attracted to other ethanol molecules then it won't evaporate as easily. Butanol has weaker hydrogen bonds so that would make the mixture percentage less likely affect the vapor pressure. I may not be spot on but I know I'm not far off lol.
 

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Am I the only one? :cool: Maybe we need a special "Gas, Mileage and Related Topics" forum here at CivicX. :popcorn:
That’s a throbbing affirmative. We can put it right before the master oil thread and after the master warranty one.

My personal favorite is the, “Hi... I drive my car with different environmental variables than you... on different routes than you... in a different style than you. How come... (insert random complaint here)”.

These ones where it’s, “Do you use the octane/viscosity/etc that the manual calls for... why or why not?” have never resonated with my soul like the aforementioned one.

Honda Civic 10th gen do you use 87 octane  in your honda ex civic. 167419DF-9A8D-4CA6-9A9E-A3B6B6247AB3
 
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gtman

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My personal favorite of the, “Hi... I drive my car with different environmental variables than you... on different routes than you... in a different style than you. How come... (insert random complaint here)”.
Yeah, my biggest pet peeve are the mileage threads. What compounds the problem is you have the guy in rural Kansas saying he consistently gets 45 mpg. Then the guy driving in NYC is upset because he only gets 28 mpg. It never seems to sink in that there are dozens of variables that effect mileage. There is absolutely no way to truly compare two cars with different drivers in different locations at different times.
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