Just to ensure the comment (assuming you're comment was directed at my post) was directed towards Ethanol fuels overall and not specifically to the blends. Where I live, getting "non-ethanol" fuel is a challenge and I know ethanol attracts and absorbs water, including water from the air.
Higher octane isn't a performance boost. Higher octane just keeps fuel from combusting under pressure. If you're running 87 octane in a high compression engine, the fuel will ignite from the compression, before the spark plug fires, and cause spark knock. Higher octane is more resistant to combusting under pressure. This doesn't mean higher octane fuels don't have other additives which do increase performance, but it is not the octane rating.
Actually didn't see your post, I think we were typing at the same time. I was merely stating that there isn't a benefit of running higher octane fuel than what is required by the engine based on compression & timing. Ethanol is another matter, corn should be used for food and wood should be used for building things or heating homes! I try to avoid it if possible.
I wondered this as well, the P5 is such a noisey little fkr I'm not sure you could hear spark knock
This is true to a point depending on where you live, most 87-89 octane fuels in the mid-west have 10% ethanol which can absorb water if it sits for an extended period. This flip side of that is in colder climates higher octane fuels can cause hard starting because the flash point of the fuel is higher.
