Fuel?


29 replies to this topic
  • dukeyaz

Posted August 25, 2006 - 09:21 AM

#21

(R+M)/2
R=RON RON is Research Octane Number
M=MON MON is Motor Octan Number

The RON is determined by chemists, and the MON is (or at least was) determined by running the fuel in a standardized engine with an adjustable compression ratio. With the engine running at a standard speed and load the compression ratio is increased until detonation is detectable.

Best to just spend the money on the premium fuel.

  • Daffy Duck

Posted August 25, 2006 - 09:37 AM

#22

(R+M)/2
R=RON RON is Research Octane Number
M=MON MON is Motor Octan Number

The RON is determined by chemists, and the MON is (or at least was) determined by running the fuel in a standardized engine with an adjustable compression ratio. With the engine running at a standard speed and load the compression ratio is increased until detonation is detectable.

Best to just spend the money on the premium fuel.

:thumbsup: Well at least I can understand the last sentence. That makes sense to me..

  • grayracer513

Posted August 25, 2006 - 10:01 AM

#23

(R+M)/2
R=RON RON is Research Octane Number
M=MON MON is Motor Octan Number

The RON is determined by chemists, and the MON is (or at least was) determined by running the fuel in a standardized engine with an adjustable compression ratio. With the engine running at a standard speed and load the compression ratio is increased until detonation is detectable.

Best to just spend the money on the premium fuel.

Both Research and Motor octane are determined by actual tests done in special test engines with variable compression ratios.
Here's a Writeup by VP Fuels that explains the differences. Essentially, the Motor test machine runs at a higher speed, higher temperature, and has variable timing as well as variable compression. Neither is actually a very good representative of a modern engine, but the Motor machine puts a good deal more stress on the fuel under conditions that are more like those seen in the real world.

Determining the octane chemically dates back to a time prior to 1950, when gasoline was mostly a blend of Heptane and Octane. A 90 octane fuel was roughly 90% octane and 10% heptane. Those days are long gone, since many modern gasolines now contain none of either chemical.

  • TexN343

Posted August 25, 2006 - 12:21 PM

#24

Would their be any adavantage of using 93 octane vs. 91 octane. I heard somewhere that it would run cooler? I really don't think my source(friend) is reliable and was just blowing smoke up my ***.

  • grayracer513

Posted August 25, 2006 - 01:47 PM

#25

No advantage whatever if 91 octane was an adequate level of detonation resistance for your engine.

The method by which a fuel blender achieves a higher or lower octane can have some effect on other characteristics, such as how fast or slow, or how hot or cold the fuel burns, the vapor rate, or any of the myriad of measurable qualities gasoline has, but there is nothing you can tell about a fuel by its octane number that will allow you to make any such observation. None of these, or any other fuel behavior is directly related to octane number in any way. It is only a measure of detonation resistance, and if yours doesn't ping, its octane is high enough.

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  • jamieyz426f01

Posted August 25, 2006 - 03:36 PM

#26

why is the petrol in the uk have a higher octane rating?, i got "total excellium" and it said it was 97 octane! the standard pump stuff was 95!?

  • grayracer513

Posted August 25, 2006 - 04:25 PM

#27

Most of the world outside of the U.S. uses Research Octane numbers, which are the highest for any level of detonation resistance.

  • flintlock28

Posted August 25, 2006 - 05:34 PM

#28

Thanks Master (Gray), for the clarification......

I am not yet ready to snatch the marble.......

  • jamiehughes

Posted August 25, 2006 - 09:03 PM

#29

i actually mix 2 gallons of race fuel with 2 gallons of premium(91 octane) no problems yet, haven't always mixed in the right proportions and my bike doesn't seem to care either way.

  • GONE1445

Posted August 25, 2006 - 09:04 PM

#30

I usually run premium 93-94 octane depends on what gas station I go too but if I am at home and am low on gas I'll put regular in I dont hear any pinging or detination she runs fine but I am just messing around in my back yard not goin balls to the walls on the trails or any thing





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