vtec.dc2

I don't know about percentage of ethanol being used in todays fuel and if there was or going to be an increase in ethanol usage.. can someone explain exactly what they've been talking about on the news? and, if there are changes in gas, will it have some effect on a/f ratio?

Muckman

iTrader: (2)

I dont think anybody uses MTBE anymore. Alot of states already mix up to 10% of ethanol into gasoline. Ethanol has a higher octane rating (113) than gasoline however its stoichmetric value is much lower than gasoline, about 9:1 vs 14.7:1. This boosts the average octane rating of the blend (usually the premium grades contain ethanol) however your engine will run leaner with ethanol. Most engines can compensate for this amount with the O2 sensor however this will be a problem with high performance engines due to their sensitivity to AFRs. Also alcohols (ethanol, methanol) contain less energy or BTUs then gasoline therefore you will get less gas mileage too with ethanol blends.

Bottom line Ethanol has a bad rep because most people dont understand it. It causes your gas mileage to suffer and inadvertently causes your engine to run leaner. Its a cheap way to boost octane of gasoline and its clean burning.

vtec.dc2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">I dont think anybody uses MTBE anymore. Alot of states already mix up to 10% of ethanol into gasoline. Ethanol has a higher octane rating (113) than gasoline however its stoichmetric value is much lower than gasoline, about 9:1 vs 14.7:1. This boosts the average octane rating of the blend (usually the premium grades contain ethanol) however your engine will run leaner with ethanol. Most engines can compensate for this amount with the O2 sensor however this will be a problem with high performance engines due to their sensitivity to AFRs. Also alcohols (ethanol, methanol) contain less energy or BTUs then gasoline therefore you will get less gas mileage too with ethanol blends.

Bottom line Ethanol has a bad rep because most people dont understand it. It causes your gas mileage to suffer and inadvertently causes your engine to run leaner. Its a cheap way to boost octane of gasoline and its clean burning.</TD></TR></TABLE>

thanks for explainig.. but how can i find out if there have been or going to be more changes made to ethanol percentage in pump gas?. my car was last tuned in early winter.. i hope there haven't been any changes to gas after that.

VTteg

iTrader: (1)

I believe that if any gas station carries a blend of anything higher than 10% ethanol, it has to say it on the pump. Anything under 10% and they dont have to label it as having ethanol in it.

If I were you, I might tune a map while running 10% ethanol. That way you will be safe to run anything as high as 10% in the future, and if you switch back to pure gasoline you should be ok.