In a recent episode of MotorWeek, as you can in the video above, Pat Goss lays out the reasons why flex-fuel conversion kits are "impractical." Using parts supplied by GM, Pat lists the things in a regular gas engine that just won't work with ethanol. The parts that must be changed to convert a gas car to run on ethanol include: fuel lines, fuel pumps, fuel gauges, fuel tank, fuel rail, capsule assembly, fuel injectors, the fuel injector computer, fuel identifier, exhaust valves, intake valves, valve seats and - last but not least - the cylinder heads must be replaced.
Pat warns against using conversion kits you find on the internet but I don't think he meant to say EPA approved kits are impractical. Early research hints regular cars may be able to use higher percentages of ethanol. Even the president, depending on how you interpret his recent comments about ethanol, may endorse regular cars using ethanol. The EPA however warns using ethanol in a regular car will cause your engine to stop working, damage your engine, increase emissions and set the emissions warning light off. We have written about ethanol conversion kits and gas cars using ethanol but don't gloss over the first lines of those articles that warn that there is a debate on the practicality of these options.