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What octane are you using in your 10th Gen?

  • 87

    Votes: 36 63.2%
  • 89

    Votes: 8 14.0%
  • 91

    Votes: 7 12.3%
  • 93

    Votes: 6 10.5%
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Discussion Starter · #1 ·
A poll to see what octane folks are using. Post comments on any mpg or performance changes you've seen. I know break-in mileage will be a factor.
 

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People who live in high altitude regions, e.g., Colorado, may be running less than 87 since less than 87 is routinely sold as Regular. For most older, dumber, cars, the car would never know or care about running 85 in place of 87 in Denver. There's some question whether this is still true. Honda is silent in the OM. Ford, in the manual for our former '12 Focus, explicitly said to use at least 87 even in high altitude areas where lower octane is sold as Regular.
 

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87-89 is fine for the Civic and I don't think you really need to go any higher than that. The average four cylinder car won't really see the advantage with premium gas.
 

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From what i have also understood using the recommended grade of gas is what you should use, anything more and you're wasting money. One video that might help to understand this a bit is this here:

If what you're currently using is working well, stick to it.

 

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Discussion Starter · #6 ·
I posed the question (and the poll) to see if the new 1.5L turbo motor is octane sensitive. The r18a motor in my '13 EX-L is oblivious to octane after an extended test with 93 E10. I am wondering if this is going to be true with the new engine in the Civic. My curiosity comes from watching the 1.4L turbo motor in the first generation Cruze. That motor was horribly sensitive to octane rating. The Cruze OM said 87 E10 was the requisite fuel, but the engine had several issues with it in high altitudes, heat, and loading. It would heat soak easily, have to turn off the A/C in the heat, and would pull timing so much that acceleration was nearly dangerous. 91 E10 would fix the problems, or you could spend $600 for an aftermarket tune. I'm watching to see (make sure) the new Civic doesn't have those sorts of issues before I consider purchase of one.
 

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The ECU controls everything, and it is calibrated for a certain octane, which of course is the octane recommended in the manual.
 

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Not sure how the octane level would affect the engine at high altitudes, heat, etc but I assume HOnda took everything into account when testing the new civic so it wouldn't run into these problems.
 

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Not sure how the octane level would affect the engine at high altitudes, heat, etc but I assume HOnda took everything into account when testing the new civic so it wouldn't run into these problems.
Yes sir, all that is part of the calibration process. I used to help build the ECU's for Honda... they take no shortcuts in engineering.
 

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Did Honda bring prototypes to high altitudes for testing? Did you get to go with the prototypes to make sure the ECU is adjusting the actuators properly?
 

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Did Honda bring prototypes to high altitudes for testing? Did you get to go with the prototypes to make sure the ECU is adjusting the actuators properly?
I worked for Keihin (Honda subsidiary) from 2005 - 2009. The calibration process is carried out in a controlled lab environment, with subsequent testing done in extreme conditions on a test track, then the camouflaged versions we see in the sneek peeks from different locations. I was involved only with the manufacturing side of the ECU's. From my observations and experiences, Honda takes no shortcuts in their engineering.
 

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That would probably explain why how their cars run overall are so good. Someone in the industry doing what you do, going from company to company and seeing what the various practices are like could probably vouch for that.

I'd be interested in hearing how American car brands compare to Honda.
 

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Running 91 burns a little higher and kicks the turbo in slightly faster as well as the injen CAI. I did notice a little difference when went from 87-91. When driving conservatively I'm able to average 44-46mpg on the highway
 

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The Engineer who developed " The new 1.5 turbo engine" clearly siad that

" higher octain doesn't effect anything at all~~~!!! "
" controled by ecu " " not by octane grade "
 

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I've been using 87 in mine and an very happy that it runs fine on it. This was not the case with my 97 Prelude V-TECH that insisted on premium fuel. Anything less and you could watch the tac bounce up and down until she got what she wanted :)
 

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I'm buying 87 Octane gas just like the owner's manual says.

Feel free to buy the 89, 91, 93 or race gas if it makes you feel better.

(I'll be taking the money I save and buying high octane, high quality microbrews to sip while I read these silly forum threads.)

Cheers!
 

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The purpose of higher octane fuel is to prevent pre-ignition (knocking) caused by high compression ratios. That's it folks. Unless you are running a high compression engine, such as a Corvette, it is not necessary and a waste. The Civic does not have a high compression ratio engine. Regular and Premium explode with equal intensity when sparked off with the engine's spark plug. One is not more 'powerful' a fuel than the other. However, Premium is engineered to resist ignition simply by being compressed.
 
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