Just filled up the tank with 91 octane premium fuel

[DerFlosser]

Possibly placebo but a higher octane fuel should ignite better so a smoother start really is possible.

[07WYarisRS]

Originally Posted by DerFlosser

Possibly placebo but a higher octane fuel should ignite better so a smoother start really is possible.

Higher octane fuel had a higher flash point... That means its harder for higer octane to ignite thats why its only to be used in high compression engines to eliminate knock...

So many people know so little about fuels and its affects its enough to make your head spin. Why people will continue to argue the effects of running different octanes is beyond me...
Run only the octane needed to prevent detonation, anything higher is waisting $$$ and costing you performance as a higher octane with higher flash point is harder to ignite and can waist fuel...
If your engine is knocking on 87 octane it either because you have a problem, your buyin shitty ass gas or you ran high octane fuels for a time and have a carbon build up problem.
i've been building and rebuilding race engines and regular engines for many years and have done many tests on the dyno and using CHT/EGT guages.
Facts are facts people. running a higher octane in a n engine that was designed to run a lower octane is not doing ANY good.. in fact it does more harm then good

[06vitzRS]

Originally Posted by 07WYarisRS

Higher octane fuel had a higher flash point... That means its harder for higer octane to ignite thats why its only to be used in high compression engines to eliminate knock...

So many people know so little about fuels and its affects its enough to make your head spin. Why people will continue to argue the effects of running different octanes is beyond me...
Run only the octane needed to prevent detonation, anything higher is waisting $$$ and costing you performance as a higher octane with higher flash point is harder to ignite and can waist fuel...
If your engine is knocking on 87 octane it either because you have a problem, your buyin shitty ass gas or you ran high octane fuels for a time and have a carbon build up problem.
i've been building and rebuilding race engines and regular engines for many years and have done many tests on the dyno and using CHT/EGT guages.
Facts are facts people. running a higher octane in a n engine that was designed to run a lower octane is not doing ANY good.. in fact it does more harm then good

+1

But i'm just a mechanic so what do i know.

It would be soooooo nice to put this topic to rest....probably not going to happen, oh well.