Originally Posted by Robert

I'm told that Ethanol burns at a higher temperature to petrol therefore the metals used need to be suitable (valves etc). I know that with LPG conversions they used to request stainless steel valves & seats. Not sure whether these are now standard, but if not, then that may explain the slightly higher cost of manufacture.

Additionally, hoses and seals need to be able to resist any corrosion. It may also be that the materials used for normal petrol vehicles are already resistant.

Lastly, the timing needs to be altered (so what as it is already all electronic anyway.)

The only other consideration is some sort of a sensor to measure the % of ethanol present in the blend and calibrate the car's timing accordingly. This is what the "flex fuel" vehicle is all about - being able to run on any blend and have the car work out the optimum settings to run with it.

This is just anecdotally what I have heard, so someone please correct me or offer some better info.