Fuel octane selection

[DylanS]

So I know the basics on what octane means, and that the higher the compression ratio is the higher the octane should be to prevent premature combustion

But I'm still experimenting with my fuel mixtures, and would like to hear what you guys have to say on the topic too

I have about 200 pounds of compression in my motor
And it seems to run best at a mix of 4 gallons of 93 non ethanol and one gallon of 110 AV gas
Maybe could be better, what do y'all run?

 

[Harbor]

Only have 91 around here no 93.... 200 psi 50/50 91/110 no long wide open.... 225 psi straight 110 or ms109...

 

[DylanS]

Only have 91 around here no 93.... 200 psi 50/50 91/110 no long wide open.... 225 psi straight 110 or ms109...

I tried half half mix and it seemed to run poorly which is odd
That should be the right mix

Thanks for the input though, I see you a lot around here lol

 

[Mike W]

I don't like to run pump gas with ethanol so I run straight LL100 avgas at 40:1. I'm at ~180 psi in my SJ and B1 and they both run just fine.

 

[Harbor]

I tried half half mix and it seemed to run poorly which is odd
That should be the right mix

Thanks for the input though, I see you a lot around here lol

Welcome, ya I should have mentioned it's not AV gas but leaded 110 race gas...

And the ms109 is unleaded gas