I run 92 octane unleaded. It is my belief that the unleaded leaves less deposits than leaded and if that is true then it is actually "cleaner".
It is also my belief that tetraethyl lead is added to prevent predetonation and detonation. For thirty years I thought that lead lubricated the valve seats in a four stroke engine. That is why you are supposed to use hardened valve seats for unleaded. But I recently found out that the lead fuel when burned, creates oxides and halides. The oxides and halides, actually harden the cast iron surface of the "soft" valve seats and create a surface hardness. Then if you switch to unleaded fuel the valve seats will survive. Now all that soft valve seat stuff only applies to 50's and 60's cars, but I thought this might create some debate.
It is also my belief that higher octane fuel when ignited burns slower than lower octane fuel, thus preventing the detonation. I think that the specific gravity is the measurement of the fuels explosiveness and that is a source of power gain. I do not know how the fuel is measured for its ability to bear oxygen. I am hoping many others will post the facts so I can learn about specific gravity and oxygen.
John
