What Octane are you running - Page 2

quote:

ORIGINAL: Kevin48

Everyone is talking about this possibility of a knock with the 87.  If its not bad to run the 93, and you get no knock, then why not do it.  Think about it, were only talking about a few gallons here.  At my gas station, the 93 is about .20 cents more a gallon than the 87, so to fill it up what are we talking about....one dollar?  As long as the 93 is ok to run, ill stick with that and pay the extra dollar, besides i dont have to worry about, or listen for any knocks.

I don't understand that rationale at all. If you don't need premium fuel, pay more for it anyway and leave a little power on the table just because you can?

For those saying that premium is cleaner, cooler burning, hotter burning, slower burning, resistant to burning, or whatever.........it is none of those things. Here are some excerpts from posts of mine in a few threads just like this one:

quote:

ORIGINAL: 65ShelbyClone

Also, octane does not refer to the rate of burn or flame speed of a fuel. It describes a fuel's resistance to autoignition. Methanol is ~115 motor octane, but it has a flame speed that is faster than gasoline. High octane is great if you need it, but it will cost power if you don't.

That autoignition can come from heating due to compression, residual heat in carbon deposits, radicals in exhaust byproducts left over from the last cycle, and even too much ignition advance. However, spark knock doesn't quite work the same way as flat out autoignition.

quote:

ORIGINAL: 65ShelbyClone

High octane fuel will not burn "hotter." Did you know that methanol has a motor octane of about 115, yet little more than half the BTU content of gasoline? Compressed natural gas has an octane rating of about 130, but 1/4 the energy content by weight of gasoline. Pump gas has a negligible difference of energy content between the grades.

The bottom line is that the F4i's ability to run on 87 R+M/2 octane fuel shows how conservative Honda and/or Keihin was with the ignition advance curve. This is especially significant considering there is no knock sensor. Another aspect of being able to run 87 fuel through a 12:1 engine is the relatively high rpm. There is simply less time for the necessary chemical and thermodynamic reactions to take place in the cylinder. An efficient chamber design also helps. I suspect that if Honda had taken full advantage of their design, none of us would be able to run anything less than 94-96 fuel.

Now that we have yet another beaten-to-death octane thread, all we need now is another "what oil is best" thread to complement it.

87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87 87

As tiresome as these threads are, I think it's very healthy for the community to be exposed to the actual factual information that ends up getting repeated on the last pages. It's what keeps this community alive lol.

my bike runs on sunshine and happiness

quote:

ORIGINAL: sluijs01

my bike runs on sunshine and happiness

 
wow...just wow...is it pink too?

quote:

ORIGINAL: Tahoe SC

quote:

ORIGINAL: sluijs01

my bike runs on sunshine and happiness

wow...just wow...is it pink too?

 
lol i think i just had a wtf moment seeing that

my bike gets 16,300 leagues per hoghead.

For my first post, I figured I would chime in.

Running a higher octane will not make your engine lose power.  Also premium gas compared to regular gas has no extra detergents or any "extra" cleaning agents.  Also, per a post on the front page, all pump grade gasolines contain 10% ethanol.  Per EPA (and a few dozen other standards and authorities including SAE and ASTM), all street grades will contain 10% ethanol and 90% gasoline (unless you are running a higher ethanol fuel, i.e. e85, 90, 100).

Please advise that running a higher octane will not reduce KNOCK per se.  Knock is the premature ignition of fuel due to high temperatures (a 87 octane will ignite before a 89 and so on).  Knock can be, and often is, a precursor to pre ignition.

Pre ignition is the the ignition of the airfuel mixture within the cylinder by a source other than the spark from your spark plug.  These points may be ring lands, valve seats, burrs on the cylinder head etc.  Knock can cause pre ignition by uncontrollably raising temperatures on said parts/points.

Long story short, if you run your engine hot all the time, it wouldn't hurt to run a higher octane.  If you have a ECU flash that advances/retards timing, it may also require a higher octane (possibly along with colder plugs).

Hope this helps,

-Westy

Knock is not a precursor to "pre ignition"; it's the result.

quote:

ORIGINAL: FLYOU

my bike gets 16,300 leagues per hoghead.

I really doubt that.

quote:

ORIGINAL: Tahoe SC

quote:

ORIGINAL: sluijs01

my bike runs on sunshine and happiness

wow...just wow...is it pink too?

of course!  I didn't buy matching pink handlebar tassles for nothing

(I figure if nobody else was going to try to salvage this thread, I will!)

Bonzai Bitches