Which kind of fuel should I be using?

Brony2012

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So I've got a 2017 Honda Civic EX-T manual transmission and I've got a lead foot, but mpg is still kind of important, so I'm not flooring it at every light, just most of them. My question is should I use a high octane fuel, or just stick with 85 octane? And is there a noticable difference in performance, or not really? Thanks everybody.
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xcoreflyup

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I think 87 is minimum requirement.

Honda Civic 10th gen Which kind of fuel should I be using? 2
 

AndyAndromeda-AUS

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91 RON in Australia is the minimum.

Depends on how much fuel costs decides what I put in it. But normally I use either 94 RON with a 10% ethonal blend or 98 RON premium but that normally costs close to 180cents a litre so yeah... I don't put that in all that often.

But I guess just put in what ever the user manual suggests... See what your mileage is and then try something with a higher octane number to see what result you get.
 

brienp

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This question pops up from time to time. An octane rating is in regards to how much compression that fuel source can take before it ignites without a spark. 87 octane cannot be compressed as much as 89 or 91 or 102 and so on. You car's engine is built to squirt fuel into the cylinders and then compress the fuel to a predetermined value and then ignite the fuel with a spark from the spark plug, the subsequent explosion then lifts the cylinder heads and the process repeats its self. If your car's engine is designed to work off 87 octane gasoline than putting 92 into it wont do you much good, because the engine compresses the gas to a predetermined value, no more.

The same is NOT true using a lower value gasoline in an engine designed for a higher value. If your car's engine is designed to work off 91 or higher that means it compresses the fuel source significantly MORE than an engine designed to run off 87. In that scenario the fuel source will be squirted into the cylinder and compression will begin, before the spark plugs can ignite the fuel will have reached its tolerance for compression and pre-detonate ramming the heads back up BEFORE they've had a chance to fully compress the fuel. This pre-detonation results in a knocking sound and over an extended period of time can ruin an engine. Most modern cars are built with pre-detonation sensors (knock sensor) that will limit the compression of the engine on the fuel source to avoid pre-detonation, but, in that scenario this will also result in a loss of engine torque.

I don't know what octane your EX-T calls for. But, if the manual says "87 or higher" then your engine is designed to run off 87. You're more than welcome to waste your money and put 92 or more into your car. It wont do anything extra though, as the gasoline will be compressed to the value of 87 octane rated gasoline.
 

hfpdohc

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i put premium in my 1.5 turbo base model and 87 is recommended...but i can see better mpg with the premium
 


IDriveACivic

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I encourage those with sensitive butt-dynos to do a blind test. Ask a friend to fill up the car for you (without telling you fuel grade). See if you can feel the difference :D
 

_HawK_

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I usually put mid grade fuel (1 step higher than minimum) in my EX-L. This is because I have read at least 3 threads that say that after testing, the 89 octane fuel gives better performance and gas mileage. Premium gives even better performance and gas mileage but the price increase does not warrant it. So, the mid grade fuel is supposed to be a better deal. I would like to know if this is the truth and final word on the subject but I am not certain.

One thing I do make sure that I do is run a tank of quality fuel through my car every 6 weeks or so. As I understand it, the additives in better fuels like BP help maintain the fuel injection system with detergents and such.
 

Goseki

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So I see in my manual, 2018 touring, that it says for any honda equipped with sports mode that 91 premium is recommended now... is this a new thing?
 

djasonw

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Have a 16 Touring. Always use regular 87 octane and get great mileage in suburban south Florida. Hi 30's low 40's. Used premium once and NO difference in MPG. Premium costs $0.75 more per gallon. Waste of money especially if not required.
 


_HawK_

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Have a 16 Touring. Always use regular 87 octane and get great mileage in suburban south Florida. Hi 30's low 40's. Used premium once and NO difference in MPG. Premium costs $0.75 more per gallon. Waste of money especially if not required.
Well that could not be less conclusive. You can know nothing by using premium one time.
 

gtman

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I switched from 87 to 89 and got slightly better gas mileage and the engine just felt smoother to me. I stuck with 89 until I got tuned.
 

Honda 4life

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My car is 2.0L can i use 89 octane too? Or ill stick to 87?
 

WVUGuy275

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I'm almost at the end of my own little experiment. Did 1500 miles on 87 octane and am working on the next set of 1500 miles on 89 octane. No significant changes in drive patterns or whatnot. I'll post when I finish up in about 500 miles.
 

_HawK_

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So I see in my manual, 2018 touring, that it says for any honda equipped with sports mode that 91 premium is recommended now... is this a new thing?
I think I read in a thread when the '18s were first coming out that this is indeed a new recommendation from Honda for the new 2018 civics. I am not sure what trim levels it applies to if it is indeed the case. But don't take that as definitive as I am only about 85% sure of myself that I read that.
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