Hey guys, had an interesting conversation with a cool older guy with a Miata that I had a run in with, we pulled into the gas station which is the one I normally go to, which is the only in town to offer 94 octane, but they blend it with ethanol. He made a comment how he drives to the only Shell station thats local to us on the other side of town, specifically to run 91 octane V power gas they offer, apparently with no ethanol blend at all.

Whats your guys opinion on these 2 options?

 

The ethanol blend will run a tiny bit leaner because of the ethanol content but the octane rating is obviously higher on the blend. I cant tell you how much leaner but probably less than 5%. However a lot of people avoid ethanol fuels because they think it will melt your fuel system but modern cars have been designed for ethanol blended fuels for decades.

 

Plus pump gas has a maximum ethanol content of 10% (e10). this means that there's less petroleum product per gallon which is done to reduce the amount of fossil fuels we use which also keeps the cost of gas low.

While some argue that ethanol free fuels perform better there really isn't a difference. 93 octane whether it has 10% ethanol in it or not is still 93 octane, as they calculate the amount of ethanol needed to keep the basestock blend at the advertised octane rating. plus to some extent the added ethanol content actually has a higher detonation threshold and cooler intake charges since the ethanol vaporizes and removes heat.

there are a few ethanol free stations in every state but they are rare and the fuel is considerably more expensive per gallon.

 

The cost between 94 octane blended and 91 octane unblended are about the same locally to me, ive wonderred the same thing which to run

 

I have tested both. The 94 from petro canada is much better. It will alow you to run 3-5 psi more boost than the shell 91.