10% ethonal blend 14.7AFR???

[damojo2003]

I have been doing some looking around and I have been curious if with a 10% ethonal blend you should still shoot for the 14.7 AFR during closed loop. I know the stock O2 sensor is most accurate at 14.7, but that is designed for gasoline not ethonal. Has anyone else looked into the optimal AFR for cruise with 93 octane and 10% ethonal blend?

[85DropTopTA]

The O2 sensor does not measure the amount of burnt fuel in the exhaust. it measures the amount of Oxygen left in the exhaust which the computer makes its fuel calculations based off.

you will see this when you fill your tank with ethonal, by watching your STFT and LTFT.

[damojo2003]

I understand that, but that does not answer my question. If gasoline stioc is 14.7:1 and ethonal is 9:1, would the stioc of the 10% blend that is required in my area be lower than 14.7:1? If so, what should it be?

[MMGT1]

Pretty much all fuel here in Canada has 10% ethanol (SUNOCO 94) and I have not seen or herd of anyone having to change the stoich settings from 14.7 to anything else.

[GTPNoga]

I found this on CLubGp. Take it for what it is.

http://www.clubgp.com/newforum/tm.as...mode=1&smode=1


The formula for blending two fuels and finding their stoic is as follows:
(stoic point fuel #1 * % by mass)+(stoic point fuel #2 * % by mass)

E.G.:

stoic point of gas = 14.7
stoic point of ethanol = 9

E85 (85% Ethanol, 15% gas)
(14.7 x .15)+(9 x .85) = 9.85 Stoic AFR

87 Octane with 10% Ethanol blend (90 gas, 10% ethanol)
(14.7 x .90)+(9 x .10)= 14.13 Stoic AFR

Open loop fueling should be adjusted accordingly.