"These additives were initially tri-ethyl-lead that presented health and environment risks so many countries have outlawed their use (with some exceptions for aviation fuel). These additives are intended to actually slow/delay combustion slightly."
"Most modern engines are designed with a moderate compression ratio that doesn’t need leaded fuel and will run as well or BETTER on low octane fuel. Remember, it’s easier to ignite a low octane fuel than a high octane fuel and that the higher octane fuel burns slower."
"Some engines are designed with high octane fuel requirements. Forced induction (turbo-charged and super-charged) engines have higher cylinder pressures so they require higher octane gas."
Lead was introduced into petrol not only to stop knocking but to lubricate the valve seats as well. Also note, TEL (Tetra Ethyl Lead) is a heavy metal compound with a short aerial time span. It was superceded because it was shown to have a supposed detrimental effect to childrens IQ. It was replaced by Benzene one of the most dangerous carcenogens known to man, that does not come to earth quickly and is actually absorbed through the skin. As they say in the USof A, go figure. Most probably cost in actual fact.
So when you fill your bikes up wear those plastic gloves supplied for filling diesel.
I think I'm right in stating that most Ducatis have a CR around the 10.5 to 11.5:1 ratio so would gain from a higher grade. My old bus takes 3 people to push start it in 3rd, I dunno what the comp ratio is but it's bloo*y high and it does make a difference sticking a higher octane juice in it. Enough to stay with a new R1 up the straight at Croft. A mate of mine had the old Laverda Formula Mirage 1200 triple. It would not run at all on std unleaded.
Turbocharged cars have a reduced compression ratio because they are forced induction. More like around 7:1 or so.
They can practically run on paraffin rather than the other way round. If they ran standard compression ratios they would reduce the engine to **** in seconds under load.
In short and in general the higher the compression ratio the higher the octane needed, although modern engine management has minimised knock and pinking so a higher CR can be used for the same grade of petrol than of old.
I also think I am right in saying our low grade fuel is actually higher than in the USofA; 87 for the US. Wos ours 90 something?
See this:
http://chemistry.about.com/gi/dynami...od4 %3Fsp=ink Ains.