My turbo car was tuned on 10 percent alcohol fuel but when I store it for 11 months I drain the tank and fill it with 93 non alcohol fuel and sta-bil when I come back it seems to run a little rich I’m almost on empty and will put 93 10 percent alcohol in and see if it makes a difference
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Does non alcohol fuel change AFRs
- Thread starter BobK
- Start date
If tuned correctly it should change with a flex fuel setup.
The nominal stoichiometric ratio of gasoline is 14.7:1 (nominal because the stoichiometric ratio changes with the fuel blend). The stoichiometric ratio of ethanol is 9:1. A 10% blend of ethanol with gas would have an aggregate stoichiometric ratio of 14.1. If your ECU is set up to hit a target AFR and you have closed loop operation off of the O2 sensors the fuel trim should be able to correct for the small difference in stoichiometric ratio and you should be able to hit your target AFRs.
If you are running open loop and the ECU fuel tables are set up based upon 10% ethanol but you are now running 100% gasoline, then yes it will be running a little on the rich side. Of course, remember that most AFR gauges come calibrated for use with gasoline and unless your AFR gauge was calibrated for use with 10% ethanol the gauge is not displaying AFR. It will display lambda accurately.
If you are running open loop and the ECU fuel tables are set up based upon 10% ethanol but you are now running 100% gasoline, then yes it will be running a little on the rich side. Of course, remember that most AFR gauges come calibrated for use with gasoline and unless your AFR gauge was calibrated for use with 10% ethanol the gauge is not displaying AFR. It will display lambda accurately.
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