Regular VS Premium

XeroReboot

Z6-All Motor
So is it common for Civics (D16Z6) to actually get better mileage on regular gas than on premium? I drive about 90% freeway and each tank is ran about the same... i get about 26 on Premium and about 29 Regular... this seems backwards since shouldn't I be getting a better and more efficent burn with premium? I've always got better MPG with premium in other cars...
 

bizoneoeh

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premium won't hurt but it's just a waste of money for your tiny little motor. I also think there's quite a few threads on this subject. did you even search before posting?
 


Deezy

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Yeah man, that's about as good as it gets with the D16...I've calculated my mpg's under all types of circumstances, and trust me, your there......Forget the premium, your wasting your money...
 

XeroReboot

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premium won't hurt but it's just a waste of money for your tiny little motor. I also think there's quite a few threads on this subject. did you even search before posting?
Yup... most were about poor mileage do to something else or asking what kind of mileage people get... I was asking if it's normal for Civics to get the same or worse with Premium (whole new thread)...
 


R3dline

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yup, regular is the way to go with a civic
 

RonJ

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Yup... most were about poor mileage do to something else or asking what kind of mileage people get... I was asking if it's normal for Civics to get the same or worse with Premium (whole new thread)...
Yep, the mileage should be about the same, so why pay the extra price. The mileage difference you saw is probably because you can't do the same exact type for driving for the regular versus premium tank. This is called sampling error.
 

XeroReboot

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i agree with both of this guys except if you do a swap i think it recommends premium gas for it ex. b16a,b18c
Well I'm used to my 4AGZE, which the sticker called for 96 octane, which has been unavailable since I've been driving lol and actually had a manual switch to push if you couldn't run premium that would change the timing for lower octane. Anyway, you guys are all saying what I figured, thanks.
 

kyle97charlie

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well, i'll use my highway miles as an example on this one


87 octane yields me around 27 mpg with spirited driving on city and highway combined.

93 octane yields me about 34 or 35 driving the same way.


and almost 40 mpg highway. I drove 180 miles round trip on less than a quarter tank of gas.


That is with my 97 Ex sedan
 

98ej8

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yeah idk my 98 coupe drives better with premium
first off it pulls better so i dont have to throttle it as much as when im using regular
and i get better mileage
btw how are you only getting high 20s?
 

DarkCreep

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I LOL @ people who put 91 in their Civics and argue that it gets better power and mileage. I have a few friends that say so, makes me lulz.
 

oc_civic

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Yep, the mileage should be about the same, so why pay the extra price. The mileage difference you saw is probably because you can't do the same exact type for driving for the regular versus premium tank. This is called sampling error.
higher octane gas DOES actually burn differently than lower octane so i think totally reasonable on a car that can not properly burn higher octane gas MAY actually get lower MPG on high octane fuel.....
 

XpL0d3r

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"A common misconception is that power output or fuel mileage can be improved by burning higher octane fuel than a particular engine was designed for. The power output of an engine depends in part on the energy density of its fuel, but similar fuels with different octane ratings have similar density. Since switching to a higher octane fuel does not add any more hydrocarbon content or oxygen, the engine cannot produce more power."

soo you NA Civic guys thinking you get more power with 93... all in your head. Learn Psychology :lol:
 

RonJ

Banned
higher octane gas DOES actually burn differently than lower octane so i think totally reasonable on a car that can not properly burn higher octane gas MAY actually get lower MPG on high octane fuel.....
The only difference between high and low octane gas is that high octane gas requires more energy to ignite than does regular gas. Thus, high octane fuel is used to prevent the unwanted problem of detonation in high compression engines. Nonetheless, a low compression Civic SOHC engine has no problem at all properly burning high octane fuel. It's just that the added feature of detonation prevention is unnecessary for this engine. In summary, regular and premium gas theoretically should yield similar gas mileage in the Civic SOHC engine. You just pay more money for the premium gas.
 

oc_civic

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Nonetheless, a low compression Civic SOHC engine has no problem at all properly burning high octane fuel.
I am not saying you are wrong but how do you know that.. my ex had an LX that actually ran better in general on lower octane gas it also did appear to get better mpg.. when she first got the car as a habit i would put high octane gas in it (ran high octane due to nitrous in my car).. but after a while we did switch down..
 

Hecz

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In a car that recommends regular gasoline, premium will not get you noticeably better gas mileage. The only advantage is a lighter wallet or pocketbook to carry around. Inversely, when regular gasoline is used in a car that requires premium, the engine’s computer changes its operation — it retards ignition timing — to adjust for lower octane fuel. This change in operation can decrease gas mileage and power.

According to the American Petroleum Institute, premium traditionally has a slightly higher energy content, which can provide better gas mileage, but any gains will be difficult to detect in daily driving. If there is a mileage advantage, it will be a far cry from saying premium is cost effective and negates the extra cost.

The main difference between regular, mid-grade and premium gas is the octane rating, which is a measure of gasoline’s resistance to combustion. It’s commonly sold in 87, 89 and 93 grades; 91 or 92 are available in some areas. Certain engines (especially ones with a supercharger or turbocharger) need the high octane go-go juice to prevent engine pinging or knocking, which can be harmful to an engine.

Before you make your car shopping decision, though, remember that a car will run best on its recommended fuel. If the car requires (not recommends) premium, definitely use it unless only a lower grade is available. You should always use the gasoline that the automaker — not the dealer — recommends. That’s why it’s always phrased either “recommended” or “required.” If you don’t know what fuel to use, check your owner’s manual
 

RonJ

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I am not saying you are wrong but how do you know that.. my ex had an LX that actually ran better in general on lower octane gas it also did appear to get better mpg.. when she first got the car as a habit i would put high octane gas in it (ran high octane due to nitrous in my car).. but after a while we did switch down..
The only explanation that I can come up with is that excess carbon build up in the cylinders was causing pre-ignition (knocking) of regular gas and someone retarded the ignition timing to Band-Aide remedy the problem. Then, when you put premium gas into the tank, the pre-ignition problem was eliminated but now the ignition timing was out of spec and engine performance and mileage were hurt.
 

DarkCreep

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What is the difference between the octane rating and the octance number?

I have a retarded friend that swears by putting 91 in his carb'd AE86. He showed me the book says to put 91, but it says "USE OCTANE NUMBER 91 (OCTANE RATING 87)".
 


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