91 or 94 Octane.

[RCMPSVT]

So my car is tuned for 94 octane with a can of boostsane octane, makes 20PSI. Took car in today to local mechanic and he was checking it out and we got talking about fuel. He told me I’m Better off running 91 octane cause after 91 all it is is ethanol blend to make it 94. I don’t plan on changing off 94 but does 91 actually run better than 91?


Curious.


Thanks.

 

[TP03]

Nah. Don't listen to that. Old way of thinking is "ethanol is bad". Only worry if any is having an ethanol blend sit for a while in the tank like during storage. Ethanol likes to attract water/condensation. More octane will always run better if your timing is advanced for it. More timing on less octane and you're asking for trouble.

 

[13COBRA]

DO NOT listen to that local mechanic. LOL

 

[DSG2003Mach1]

leave it be with 94 + boostane. Even if they were just blending #85 with it to bring it up from 91 (which i doubt) the anti knock/detonation properties of it would be a bonus not a bad thing.