87 Octane

[1929]

Originally Posted by 1crosscut

1929

High octane fuel is more difficult to burn. It is used on high compression engines to help prevent pre-ignition / pinging.
In a high compression engine fuel will want to ignite prematurely due to compression sort of like a diesel engine ignites fuel from pressure.
Using high octane fuel that is more difficult to ignite solves this issue.
Stock Model A's do not have this problem and will run better on the lower octane fuels.
Has anyone had troubles with pre-ignition / pinging with a high compression head on their Model A?

I have a 6-1 Head

[Mike V. Florida]

Originally Posted by 1929

I have a 6-1 Head

Still low compression as compared to the 12.5:1 engines that require 91 octane.