Phat Kat wrote:
Thanks Morris, thats some pretty interesting info... Did you find that adding toluene had any negative side effects?----How the hell did you strike up that kind of deal with Ampol you lucky bastard!? It promts me to ask the question... Its obvious that you had some "history" with our mutual ""friend""

Mr ******, and I've seen you mention your racing history a few times too... May I be so bold as to ask what your racing back ground is/was? It sounds pretty interesting...
I only ever used the free toluene in the F100 tow car as the class I was in at the time required pump fuel and they used to take fuel samples at random meetings. The F100 used to ping on city grade super petrol so five litres of toluene used to stop the ping.
I never actually had anything to to with Mr ****** but his reputation preceded him. I did pit crew for his brother and nephew at a meeting
once.
Phat Kat wrote:
albino235 wrote:
My understanding of an octane number is that it relates to the speed at which the fuel burns and not to the power potential of the fuel. It directly relates to the knocking characteristics of the fuel, therefore the engine CR should be matched to the fuel or vise versa and so there is not much point uping the octane over what is required.
Yeah, thats what/how I understand Octane aswell Albino,, it relates to not just to heat but how long it burns for... and not a direct indication as to how much power you will get out of the fuel,,, its more a case of being able to wind up your timing that little bit extra bit to get the most out of it and also being able to utlise a higher CR,,, and of course just the fuel alone won't make a difference, its gotta be a good combo of dynamic compression ratio, timing, and fuel (and obviously in dynamic CR cam timing too)...
Now you can (I'm 99.9% sure) add stuff into fuel to stop a motor pinging with out improving the way that the fuel burns,,, I'm not really out for an RON or MON reading for that reason (because it I don't really think it is a true representation of how efficiently fuel burns more just that It won't ping till the CR is ramped up to figure X.),,, I'm more just proof that some of these additives might assist in producing better power figures...
The octane number is a measurement of resistance to detonation. It is nothing more and nothing less.
The MON and RON are two different systems for working out the resistance to detonation. (MON = Motor Octane Number, RON = Research Octane Number) Both systems work but everyone always always follows the higher number (penis measuring contest)
There is more energy in some lower octane fuels but they detonate (ping) in high compression engines.
When I was racing the HQ Holden we originally had to run on Super petrol which had an octane of about 97. We had detonation problems due to running very high compression. It was a juggling act to keep the pistons in the thing! So after a couple of years when Super was going to be phased out we were allowed to run Avgas. There is a lot of myths about Avgas. All it is is 100 octane petrol. It is not rocket fuel. (rocket fuel is actually the hardner used in most types of plastic bodyfiller!

)
So when we could run Avgas our detonation problems were over, until we decked the block and head and bumped the compression up a couple of points!
