those who tell that theres no benefit - are probably dont understand the true purpose of the gasoline

Yes there is a better milage and yes there is a better explosion and yes longer life for Catalyst and O2 sensors

Fill up 93 from the factory on stock

 

You'll have to back that up with some facts because it sounds like a misguided opinion to me. Using a higher grade than required can accelerate wear on emissions components and does nothing but make you feel better about spending an additional 20 cents per gallon.

http://chemistry.about.com/library/w...abyb100401.htm

http://www.thecarconnection.com/Car_...212.A3031.html

http://www.cartalk.com/content/colum.../April/08.html

http://www.straightdope.com/columns/041008.html

 

which facts should i back off on?

 

Back off???

I said some facts to back up your claim.

 

FACT: The ONLY way to prove better mileage from higher octane is to have the test done in a controlled enviroment on a dyno, (same wind direction/speed, temperature, humidity, etc. You cannot do this on daily or even hourly conditions. By the time you drive a specific distance and refill - conditions change. If it could be proven, you can bet the petroleum companies would jump on it.

Higher octane -more power? Just a more precisely controlled detonation ONLY necessary for higher compression engines.

Believe it or not.

 

The manual for my 2004 Accord v6 says that 87 fuel is fine for my vehicle. Today, one of those parking-lot-fix-it guys said that there was water accumulated around the tailpipe and this was an indication that the gasoline that I have been using ("regular") is of an insufficient octane, that I need to use the next grade up; that I probably need to get my spark plugs changed.

So, what is the real truth? Am I to believe the manual of the parking lot mechanic? I have to say, that after five years of ownership of this used vehicle and many fill-ups of of regular unleaded fuel, the car has not given me a moment's trouble. However, am I to expect inappropriate-fuel-related breakdowns down the road? I am less concerned about gas mileage, as I am about unnecessary wear and tear on vital parts. Professional wisdom will be greatly appreciated.

 

Tell the stupid and uneducated slob to buzz off; he doen't have a freakin' clue what he's talking about. The highly educated Honda engineers that designed and built your car know exactly what your car needs; regular fuel. The fact is, the two main by products of combustion are Carbon Dioxide and, yup, you guessed it, WATER. Changing the anti-knock rating of your fuel won't do squat for water accumulating around your tail pipe; only heat can do that. Drive the car until it is fully warmed up and there won't be any visible misture around the tail pipe, and if there is you've got much-MUCH bigger problems than the grade of fuel you're using.

 

Duh.... I kinda thought this might be the reply (the obvious). Still, when you're ignorant on a subject, it is nice to get validation. Thanks for that.

 

I've always been told the only dumb questions was the one which went unasked. Fuel and fuel grades is one of the areas where misinformation is rampant so it is easy to be given bad advice.

 

It's really misleading to call it "high-grade" gasoline. It's a different anti-knock index, NOTHING MORE. The engine designer can choose a higher compression ratio to get more power, and that high compression in turn might require a higher anti-knock rating.

There's a few Honda engines like that, but not your stock 2004 Accord V-6.