Quote:
Originally Posted by flynjay
The point is that fuel quality has nothing to do with the octane rating. The quality is determined by what station you go to and where they get their fuel from, how it's delivered and how it's stored.
The "Octane Rating" is a measure of the tendency of gasoline to resist self-igniting using isooctane as the reference benchmark.
So a gasoline with an octane rating of 87 will be equavelent in self-ignition resistance to a mixture of 87% octane and 13% heptane.
But a higher octane rating does not equate to more energy in the fuel, cleaner burning, or inherently more performance.
In modern cars with variable valve timing. Higher octane rating does equate to higher performance for the simple reason that the engine controller is changing the timing to prevent knocking. When running higher octane fuels the valve timing can be more advanced for a performance gain.
I do not know of a bike that has variable valve timing. The 250 clearly doesn't.
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Quality may have been the incorrect terminology. Overall quality of the fuel varies on several factors to include: production, on-site storage, shipping, final destination storage tanks, temperature, relative humidity, ground water table......
All of these factors will determine the quality of fuel.
I worked in Petroleum, Oil, and Lubricants (POL) during my time as active duty Air Force and part of the job was to quality check the JP-8, Diesel, and MOGAS along with storage tanks.
Octane is the stability of the fuel during the combustion process which is documented as 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O.
Higher octane rating decreases the chance of detonation which for the most part is not a problem.
In modern vehicles variable valve and spark timing will help to achieve combustion at the most opportune moment.
Variable valve timing may increase performance over a wide rpm band by changing the lift and duration the valves are open.
During the combustion process all valves are closed so the engine can achieve compression, now variable spark timing comes into play to achieve "perfect" combustion.
Designed high compression engines or a modified engine using high compression/oxidizers running a lower octane fuel will be prone to detonation much like operation of a diesel engine.
Additional factor is fuel temperature when introduced into the combustion chamber, higher ambient temp with lower octane fuel can also lead to detonation.
Seeing how in my location I am already running below recommended fuel which has not been a problem in the fall/winter months but during summer when ambient temps are normally 100+ here in the desert leading to higher resting temp of the gasoline pre-detonation is something I have to keep a watch for.
Another prime example is the difference of diesel fuel and the paraffin content between summer and winter.
The ninjette will not benefit at all from running any higher octane fuel.