90 Octane pure gasoline

[YouDontGnomeMe]

So, I know we're supposed to use premium, 91 octane minimum in our MSP. There's a gas station near me (Atlanta area) that sells non-ethanol pure gas, but only at 90 octane. Would that be alright to use, or does it have to be at least 91?

 

[BOOSTR]

The simple fact of the matter is our MSP's will run on 87 octane. So no reason why you could not put in the 90 octane. Afterall our engines are virtually identical to a normally aspirated Protege. I've ran mine on several tanks of 87 for thousands of miles with no negative results.

Only thing I do differently is too stay out of boost. I would not push the car with the lower octane. But in my experience it runs great and there is no difference when driven normally.

 

[YouDontGnomeMe]

Really? Mine ran like utter s**** when I put 87 in mine when I first got it. Used about 2 tanks (didnt stay out of the boost tho), and i've never gone back to it, altho the engine's kinda clanky ever since...

 

[Jedidiah55]

its complicated to describe octane ratings
they are a measurement of the unlikeliness of the gas to detonation early
higher octane the less of a chance it will detonate prematurely
our system uses two systems to calculate the octane rating
the Research Octane Number (RON)
and Motor Octane Number (MON)
ours takes both ratings and averages them together to get Anti-Knock Index (AKI)
ethanol increases octane rating but decreases power unless you run 100% ethanol and due a major tune up
E85 has an octane rating of 94+
and 91 octane should give you better gas mileage
just some random info

 

[YouDontGnomeMe]

So, if ethanol increases the octane and mileage, it's better than pure gasoline then?