The Low-Down on High Octane Gasoline
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Joined: Dec 1999
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From: Lakeville, Minnesota, USA
Originally posted by bikenut
And BTW, Ethanol is not added to boost octane, it's there to help emissions.
The proof is in the pudding, test it out and you will see that if you run a tank of each in the same conditions, you will get better mpg on the good stuff.
X"
And BTW, Ethanol is not added to boost octane, it's there to help emissions.
The proof is in the pudding, test it out and you will see that if you run a tank of each in the same conditions, you will get better mpg on the good stuff.
X"
Try buying gas in many corn belt states. In most cases, 87 octane will not have ethanol, but 89 and 91+ octanes do. Again, the ethanol provides the octane boost.
In general, ethanol is used for emissions, but it not the ONLY reason its used.
Tough to make blanket statements when there are so many exceptions to the rules.
As far as using different grades and seeing a difference? Been there, done that. My' 97 has almost seven years of meticulous fuel records, using regular (87 and 85 octanes) and premium gasolines. Statistically ZERO difference (premium was actually 0.2 mpg lower).
Sorry to rain on the parade...
Last edited by gopher; Jul 26, 2003 at 04:16 PM.
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Joined: Oct 2002
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From: Costa Mesa, CA.
I suspect the blending methods in others states vary from those here in CA.
What is the max. allowable Ethanol percentage back there?
Here in CA. all grades have Ethanol and our premium is now 91 R+M/2
What is the max. allowable Ethanol percentage back there?
Here in CA. all grades have Ethanol and our premium is now 91 R+M/2
Senior Member
Joined: Dec 1999
Posts: 749
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From: Lakeville, Minnesota, USA
By State Law, all of our gas has 10% ethanol in it, except at select retailers that offer non-oxy premium for use in engines that cannot handle the ethanol (generally vehicles made pre-1988 or so) and for off road uses (boats, snowmobiles etc...). State law has been in effect since 1996.
In general, gasoline can contain up to a 10% ethanol blend with no adverse affects on engines designed for straight gas.
You can buy E85 (85% ethanol) pretty readily up here. Its 100+ octane, and generallly runs about 20-25 cents cheaper a gallon, but will get you 25% less fuel mileage than gasoline due to the lower energy content. It can only be used in vehicles designed for Flexible Fuels.
If you are getting 91 octane with 10% ethanol, you are really getting around 88 octane gasoline blended with 10% ethanol to raise the octane to around 91. Burns just like regular 91 octane, just less fuel economy. Good for corn farmers, bad for you.
In general, gasoline can contain up to a 10% ethanol blend with no adverse affects on engines designed for straight gas.
You can buy E85 (85% ethanol) pretty readily up here. Its 100+ octane, and generallly runs about 20-25 cents cheaper a gallon, but will get you 25% less fuel mileage than gasoline due to the lower energy content. It can only be used in vehicles designed for Flexible Fuels.
If you are getting 91 octane with 10% ethanol, you are really getting around 88 octane gasoline blended with 10% ethanol to raise the octane to around 91. Burns just like regular 91 octane, just less fuel economy. Good for corn farmers, bad for you.