i usually use 87 octane fuel, but my friend says that 93 octane is better for your engine. i have a 95 accord ex with 175k on it. i was wondering if i switched to 93 octane if it would mess up my engine somehow or have any disadvantages. does anyone know anything about this?

 

this has been covered many times, i would search to find your answer. but it can actually be worse. to run your car at optimum efficiency, only use what the owners manual states, which is regular fuel.

 

That's how the gas companies get you at the pump....by preying on assumptions and insecurities.

Just get 87....the engine was designed that way.

 

Agreed. The V-6 will respond to higher octane but it is a waste of time and money for the 4 cylinder.

 

why will the v6 respond and the i4 wont?

its a waste of $ unless its required.

 

i have the same type of car with 175k on it as well. I use synthetic oil with no leaks and use premium fuel. Personally, I never got a chance to know what 89 octane performed in it. I put 93 in it since I got it. No smoke, No knocks, i'm happy with it.

 

Wish I had 93 octane here in Cali. Highest we have is 91 octane.

 

Technically I don't know. The engineer that designed the engine said an additional 10 HP was available from the V-6 using premium fuel.

 

Without better information, I can take a reasonable guess..

The 4-cyl ECU has maps for spark timing & mixture over the operating envelope of the engine. The knock sensor can retard the spark from that map, but the ECU is probably not programmed to advance the spark beyond the map. So if the knock sensor is NOT hearing any knocking, it won't go hunting for the point of incipient knock.

Maybe the spark map for the V-6 is set up with enough advance sothat the ECU has to pull back the spark when it has 87 fuel?? I was not aware that Honda would have done this...

 

That sounds correct now that you mention it. I forget where I read the article but it was straight from the3.0l V-6 engine designer@ Honda. Some intense googling may bring it up.