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      11-17-2012, 02:12 PM   #1
Second Lieutenant
NoTempoLimitN54's Avatar

Drives: E92 335i
Join Date: Sep 2012
Location: Los Angeles, CA

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EPA rejects bid to relax Ethanol mandate, E85, E15, reformulated gasoline

NOVEMBER 17, 2012 AT 1:00 AM


Washington — The Environmental Protection Agency on Friday rejected a request from eight governors and nearly 200 members of Congress to waive requirements for the use of corn-based ethanol in gasoline, after last summer's severe drought wilted much of the nation's corn crop.
Source: The Detroit News:

Among BMW enthusiasts, I see a lot of conflicting opinions on ethanol as a fuel.

The "old school" seems to hate it. Mike Miller (BMWCCA tech advisor) describes ethanol in gasoline as a "contaminant".

On the other hand, some of the "new school", the N54 twin-turbo tuner guys seem to love ethanol. Many are running blends with 30% - 50% ethanol. I saw one guy claim to be running 100% E85 in his 335i.

So what do you guys think?

Here in California our "CARBOB" blendstock gasoline is most likely about 89.8 AKI, to which they add 5.7% ethanol raising the octane to 91 AKI at the pump. We can't readily get higher than 91 AKI octane here (the only alternative is 100 AKI race gas at limited locations for $7-$10/gal).

Adding another 4.3% ethanol to CA 91 AKI gasoline would raise the total ethanol to 10% (E10 fuel) and raise the octane to right around 92 AKI.

Adding ethanol to gasoline raises the octane rating, but diminishing returns set in early. Past 10% (E10) it seems you would have to keep increasing the amount of ethanol you have to blend into the gasoline or each AKI point you gain.

CA base premium gas. 89.8 AKI (at 0% ethanol)
+5.7% ethanol 91 AKI
+10% ethanol 92 AKI
+15~22% ethanol 92.5~93 AKI (interpolated)
and so on...

For Sale: 2009 335i 6MT (E92/N54), Sport / M-Technic / no iDrive / Black Sapphire / Black Dakota Leather, ZCW, 6FL, PDC, 19" VMR VB3, Pilot Super Sport, M3 control arms + tension links (fr) S. California

Last edited by NoTempoLimitN54; 11-18-2012 at 03:56 PM.