Originally Posted by 1MOREMOD
Is a tuned car less able to deal with lower octane gas or does it still retard the timing in a similar way so no damage occurs. Conversely would using a higher octane than you are tuned for be a waste or can the tuned ecu manage to adapt and make more power?
My Ess tune for the 1M would adjust for higher than tuned octane, don't know for lower though.
My Cobb tune for my old STI wanted just the gas it was tuned for I think.
But I used to put 91 instead of 94 all the time in it and never noticed pinging or whatever else.