[Healeys] Ethanol

[Bob Spidell]

I believe the European octane ratings are Research Method only, which reads 3-5 points higher than US (R+M)/2. So, European 98 octane would be equivalent to US 93 octane (rare, but available in some areas in the States; 100-octane is available for boat engines around Havasu). 

Contrary to popular belief, ethanol can actually raise octane. There's a gas station in Los Altos that used to sell 95-octane, which was E10 IIRC. It's very difficult to raise the octane rating of pure gas--it requires special refining--that's why TEL was added starting around WWII for high-compression fighter engines (it was 'discovered' at the Sloan-Kettering institute, who tested several thousand compounds before settling on TEL). Adding ethanol to gasoline means the gas part doesn't have to be as carefully refined (hence 'cheaper'). There is an exhaustive research program being undertaken in order to develop an aviation fuel to replace 100LL--100-octane, 'low-lead,' which I believe is 'only' 2 grams/gallon of elemental lead vs. 3 grams/gallon of previous formulations--and it is proceeding very slowly due to its complexity. 

I've run tanks of E10 and tanks of pure gas, and didn't notice any significant variance in mileage, but it's usually an 'oranges-to-apples' comparison since most runs involve a mix of highway/freeway and grades, stop-and-go, etc. 



----- Original Message -----

From: "John Spaur" <jmsdarch at sbcglobal.net> 
To: josef-eckert at t-online.de, "Oudesluys" <coudesluijs at chello.nl>, "Forum' 'Healeys" <Healeys at autox.team.net> 
Sent: Thursday, January 26, 2017 10:54:48 PM 
Subject: Re: [Healeys] Ethanol 



Wish I could get 93 octane let alone 95 or 98! 



John 

San Jose, CA 



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