Justin is right about what the octane rating is.
(see http://www.shell.ca/code/motoring/encyclopedia/gasolines/octane.html
for the simplest and best description I've found)
The thing is, ignition timing is the quick fix. Really there are many
factors that cause pinging.
1. Ignition timing
2. Valve timing
3. Compression ratio
4. Carbon deposits build up
5. Wrong spark plug
6. Fuel mixture and atomization in the manifold
7. Oil mixed with fuel (2-strokes only, unless you have a very worn
engine)
and more.
The octane rating has nothing to do with power the fuel produces, only the
pressure that can be exerted on it prior to, and during, combustion (without
detonation), which should result in more power from the engine. The correct
fuel to use is the one that allows your engine to be tuned to maximum
performance without pinging. To get more power there are fuels blended with
alcohol and/or ethanol that burn hotter and faster (talk about home brew ;-)
That all said, I run a fuel 3 octanes high than recommend for my engine in
case a supplier blends cheaper fuel with what I require. I also carry a
bottle of octane booster in case I cannot get what I want. My engine is not
designed for leaded fuels so I must use normal automotive fuels, avgas and
most high performance fuels are out.
Full power in the air and no problems, a few cents a litre is cheap :-)
My 2 cents worth.
regards
Barry Kruyssen
Cairns, Australia
AUF 19-3873
[email protected]
http://users.tpg.com.au/barryk/KR2.htm
> Please correct me if im wrong but octane is the rating which dictates the
> flash point, at what temprature the fuel will explode... early and late.
> Adjusting the mixture can only offer a limited amount of cover-up for
this.
> For different octanes the timing will need to be different. So if im right
> the timing is what needs to be changed with the octane.
>
> New cars have "ping-sensors" which retards the timing if it suspects
> pinging. For example: if you use a higher that whats tuned for octane your
> firing will be late, thus giving less power, so if you were to advance the
> timing in this situation you would get more power and vise vera with
> different grades of gas.
