[Spridgets] Ethanol from Oak Ridge's perspective.

[Dean Hedin]

Here's some good scientific data on ethanol blends and the effects on
rubbers, sealants and metals.  It's very current.

http://info.ornl.gov/sites/publications/files/Pub27766.pdf

I haven't read all of it.  But after skimming through it I've come to the
conclusion that I am not worried until they start to go over 15% ethanol
blending. 

E10 does not appear to be much worse than high aromatic, winter blended,
regular gasoline with respect to seal swelling and rubber shrinkage.

According to this document, blending beyond 10% could happen real soon:

"However, the amount of ethanol that may be blended and sold as an additive
to gasoline is restricted to 10% by volume (E10) by the EPA. 7 A small
amount is sold as E85 (gasoline containing 85% by volume of ethanol) for use
in flex fuel vehicles (FFVs), but most (approximately 90% of dispenser
product) is sold as E10. In 2012, the RFS will require over 15 billion
gallons of renewable fuel, but the renewable fuel mandate will continue to
increase. Assuming that most of the RFS is met using ethanol, gasoline
blenders are likely to hit a limit in the next few years, since 10% ethanol
cannot likely exceed 14 billion gallons per year. This "blend-wall" is the
maximum possible volume of ethanol that can be achieve with E10. Because of
this limitation, there is interest in increasing the allowable concentration
of ethanol in gasoline to meet the RFS 2022 mandate to "intermediate-level"
blends, ranging from 15 to 50% ethanol by volume."

So in a few years we might have something to worry about. Rubber fuel line
to handle the higher blends won't be a problem.  I'm more worried about
those seals on the little plastic hoses that go from the floats to the main
jets on the SU's.  I think the mixture enrichment can be accommodated by the
main jet adjustment on the SU's to handle the higher ethanol blends.  Folks
with Webbers will have some work to do.  

On the up side it's nice to know that the octane rating of the fuel will go
up.  So when the time comes you might want to consider getting the head
milled to raise the CR.  We may witness the disappearance of the regular and
mid octane grades at the pump once they start blending beyond 50%

Oh yeah, maybe get rid of the rubber tipped float needles in favor of metal
ball Gross jets (If they are still available?)