A sub-heading in a news report from the National Renewable Energy Laboratory (NREL) sums up recent testing there on blends of ethanol beyond 10 percent -- the cars don't seem to mind.
The vehicles used in the lab's tests on E15 and E20 represent a cross-section of cars currently in use, 16 vehicles ranging from model years 1999 through 2007 with odometers reading from 10,000 to 100,000 miles.
"So far nothing has jumped out at us and vehicles don't show a significant impact with ethanol blends of 15 and 20 percent," said Keith Knoll, senior project leader for NREL's Fuels Performance Group.
Testing shows that as ethanol content increases, tailpipe emissions stayed largely the same, with carbon monoxide emissions declining for all of the ethanol blends.
The article states that, generally, the tests have shown no big surprises or short-term effects when using greater blends of ethanol in existing cars.
The full article is available at this link: http://www.nrel.gov/features/20090918_ethanol.html