Fuel Preference
Race Director
Joined: Jan 2002
Posts: 15,342
Likes: 2,717
From: Close to DC
C2 of the Year Finalist - Modified 2020
I will go out on a limb and say many run 91-93, some, including myself run 89. It will depend on how an engine timing is mapped, known compression ratio, driving environment and how fresh or tired an engine might be. I sure others CF members will share their own details. 
Dennis
Dennis
Safety Car
Joined: May 2007
Posts: 3,677
Likes: 646
From: Indiana
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 Corvette of the Year Finalist - Modified
2024 C1 of the Year Winner - Modified
2023 C1 of the Year Finalist - Modified
2023 C3 of the Year Finalist - Unmodified
2022 C1 of the Year Finalist - Modified
2020 C1 of the Year Finalist - Modified
2019 C1 of Year Finalist (performance mods)
2018 C1 of Year Finalist
I use 91 octane non ethanol fuel.
