BP/Amaco refines about half of the fuel in the US. They operate the largest single refinery. So you really don't know who produced your fuel originally. I just use on brand and stick with it if I can. On the compression issue: wrong It has to do with the tuning. My girlfriend 89 Prelude runs a stock 9:1 compression and knocked horribly when she didn't put in 91(Honda recommended) octane or higher. It has to do with how the car is tuned. The higher strung cars such as the S2000 and Prelude were tuned from the factory more for performance so they need the higher octane gas to avoid knocking. Cars such as the Accord and Civic are set up for a balance of fuel economy and power. This allows for use of a lower octane gas. Honda recommends 87 or higher octane for the Accords. The higher octane will not hurt the car but you are spending extra money that you don't need to. Both me(03 4cyl) and my friend(04 V6) run 87 and have had no problems with performance or mileage.

 

was your g/f's car the sohc or dohc? just curious

 

I actually noticed a big difference going from using 87 to 89. so from now on i use 89 in all my cars. not only does it help clean the engine better and reduce the amount of gas particles left behind, it gives you a little kick of performance as well. i especially felt it on acceleration.

 

It is dohc. Last year our master tech was at Honda school and they went over the octane debate. Per Honda info that they were given only about a 1mpg difference was found when 91 was used instead of 87. They found both no extra deposits nor extra cleaning ability from using a higher octane.

 

*nods* i understand that, I just never really knew the cutoff point for compression on each octane level. Found out earlier today that that most effective octane for a 10:1 compression engine is 87, and i cant remember who said it, but higher octanes do not burn slower. I just assumed 89 was a better choice cause most every place you go 87 has ethanol.

Is the ethanol myth true to where it can in some cases harm engines?

 

I'm not trying to be a wise *** here, just backing up my statements:


In most of the U.S., regular gas has an octane rating of 87, midgrade gas is 89, and premium is 91 or 92. (Octane ratings are lower in the mountain west due to the effects of thin air on internal combustion.) Contrary to widespread belief, the octane rating doesn't indicate how much power the fuel delivers; all grades of gasoline contain roughly the same amount of heat energy. Rather, a higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.
First off- Octane. Race cars and high performance vehicles have higher compression engines and more advanced ignition timing. This higher compression can cause premature detonation (relax guys, it happens to everyone once). To remedy the premature detonation a slower burning fuel is used.[ Higher octane numbers mean that the fuel burns slower. The slower burning fuel can be compressed at a higher ratio without as much fear of deadly premature detonation, commonly called "pinging." Pinging will definitely ruin your engine. In modern engines with aluminum pistons this is an absolute engine killer. With modern replacement engines starting at $2000 + installation for cheap cars and up to $20,000 for some higher end cars, it's not something to ignore.


Ethanol, depending on the concentration, can indeed cause major problems when used in a car not designed for it. For instance, running E85 in a 7th gen Accord is a big no no. Ten percent is the max the car can stand according to the owners manual.

 

Yo Tex ...seems as you got this post handled...as you usually do..

WheelBrokerAng[sm=americanasmiley.gif]

 

Thanks. Just trying to post factual answers to honest questions.

 

hey yea the gas itself doesnt give more power...your engine does. the computer will notice the higher grade fuel your using (because of the adsence of any detonation) and effectively advance the timing, unquestionably yielding more power at all rpm levels. just to clear it up though. every honda out there can easily run on regular 87 octane gas. the computer will retard the timing to a point that the engine runs safely, reducing power. even on my 3.2 tl which has premium unleaded only written on the dash, the gas cap, the owners manual, and probably other places. when i called the dealership they told me i can easily use 87 and not have any problems. so should i do it?.....sure....just as soon as i stop over at my local jiffy lube for some bulk penzoil.

 

You are absolutely wrong. Higher octane than required in a computerized car that calls for 87 octane WILL NOT advance the timing. The exception is in a car like yours that calls for premium fuel and has run a tank of 87 octane. Once filled up with the correct fuel it will return (slowly) to the previous timing.

I'm with you on sticking with premium when the car calls for it. To go with less octane in a car that requires premium is foolish. The only way you'ld catch me at a Jiffy lube place is if I had a flat tire right in front of it! I am pro synthetic oil and bought up all of the Mobil 1 0W20 that I could find when I found out they were going to discontinue it.

We are waaayyyy off topic here and we've hijacked the thread. Guilty, I apologize.