does ethanol in gas kill need for gasoline additives?

[Blue_Goose]

Most stations in NH have switched over to a 10% Ethanol blend...the stations that used to tout MTBE now have the Ethanol label...my Matrix has not missed a beat with the Ethanol blend and in fact has posted some of the best mpg's I have seen with it. Usually 33-34 mpg now....I usually fill up at the same Mobil station with the Ethanol blend but 2 fillups ago I went to a station that didn't have the Ethanol stickers on the pumps...I got the worst mpg I have gotten in 2 months on that tank...coincidence?

Goose

 

[e36'n]

Does anyone know if the ethanol gas has an effect on octane? For example is a 91 Shell the same octane as a Mohawk 91 w/ethanol?

 

[GT Mike]

quote:

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Originally posted by e36'n:
Does anyone know if the ethanol gas has an effect on octane? For example is a 91 Shell the same octane as a Mohawk 91 w/ethanol?

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10% ethanol will raise the octane about 2 numbers. If you start with a base gasoline with 87 octane, and add 10% ethanol, your end product will be in the 89-90 range. So to keep the octane ratings the same as the non-ethanol competitors, they use a base gasoline with a lower octane rating. An 87 octane E10 gasoline starts out as 85 octane before the ethanol is added.

 

[e36'n]

So with a turbo car, the 94 octane with ethanol should be better than a normal 91 shell gas correct?

Thanks.