91 octane

  1. S

    E85 as a 91 octane booster?

    I've done some googling and still haven't found anything that seems to answer this clearly. Sorry if it's been hashed out already. I live in CA. We only have 91 octane fuel. I do have E85 near me. Without doing ANY mods or tuning, can I add a couple gallons of E85 to each tankful of 91 just...