On 2007-01-18 17:33, Boezack wrote:
Doc,
Would you ever use stabilizer in oxygenated gas. A service manager told me that the speedy is not tuned to run on oxygenated gas and stabilizer can alleviate the problems associated with that gas.
There are basically two oxygenates in wide spread use in the USA, MBTE and ethanol. The EPA and CARB rules concerning what fuels can be sold where are truly byzantine. Something like 500 different blends are required throughout the country at various times of the year. So when you say "oxygenated gasoline" it is a little less specific than saying "beer".
All the oxygenated gasolines are designed to lean out your combustion by providing additional oxygen in the fuel. This is only for the benefit of old carburated vehicles in the fleet and during cold start of all vehicles. When we are running closed loop on a fuel injected vehicle the oxygen sensor is correcting for the different fuel and it makes no difference. In open loop conditions the oxygenated fuel will run lean on the order of 2 to 4%.
I don't think that any fuel stabilizer, in the normal concentrations, will be able to make any difference in the A/F ratio. So in general, I avoid oxygenated fuels when possible but don't sweat it if I have to buy them. The MBTE does fewer bad things to your engine but there are more environmental concerns in ground water etc. The ethanol will pick up water, increase corrosion and seal swell. However, the maximun concentration of 10% should not hurt any modern fuel system. E85 is a whole 'nuther story. Don't even think about using it in Speedy.