Dumb question: regular vs premium gasoline?

syncro87

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The turbo cars will run just fine on regular 87 unleaded.

The computer can easily adjust the timing appropriately for the fuel you are using. On the Sport models, premium is recommended because Honda advertises that car as having slightly more horsepower. For the car to generate the advertised power, premium fuel is necessary. The "brain" in the Sport cars has been programmed to advance the timing a little bit to generate a touch more power if premium fuel is available, producing a modest power bump. The timing map or programming on the non Sport trims has a slightly narrower or more conservative range.

The 91 recommendation does not mean that the engine needs 91. It will run along happily on 87 indefinitely. The computer will retard ignition timing a touch to prevent knock / ping if detected on lower grade fuel. A small performance loss will occur. But no damage will occur, the engine will not suffer any horrible fate. Modern engine controls are such that 87 works just fine. You aren't going to blow anything up by using 87, and the dealer techs aren't out there sampling Civic fuel tanks for regular grade gas in a quest to deny warranty claims as some have theorized.

Back in the day, you used to run into situations where cars would ping in hot weather on low octane gas. Those days are mostly over due to much better cylinder head design, better head cooling, far superior electronic engine management controls. The worst thing that will happen if you take your Civic to the Mojave desert for 0-60 runs is a more conservative timing map employed by the ECU and slower times. Well, you might get a cactus thorn in your tire as well.

The only reason I see to run premium fuel is to get gas that's ethanol free. In my area, the only way to get ethanol free gas is to buy 91 octane. 87 sans ethanol isn't available locally. The benefit is ditching the ethanol, and the higher octane number is a secondary bonus.
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