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Since pump 93 contains roughly 10% ethanol content and AFR for pure gasoline is 14.7, is the actual AFR slightly richer than 14.7 even though the gauge says 14.7 because of added ethanol content?

We know pure gasoline is 14.7 and E85 is 9.8, is there a way or formula to calculate AFR for any blend like E30?

I understand using Lambda is the best way to tune multiple fuels and aiming for the same gauge displayed AFR will get the right results, but just curious how to get the correct AFR for each blend on paper.

I tried to calculate by adding the two fuels by percentage for E85: (0.85x9.8)+(0.15x14.7)=10.5 which is leaner than 9.8 so it must be wrong.

Lambda 1 is always stoichiometric ratio for any fuel, is there a scientific scale for WOT operation with different blend or is the difference so small that we can ignore and just use common Lambda values for all fuels?

Sorry if everything above is explained in future courses, I just started with the basic course and this has been bugging me.

What is wrong with 10.5 being leaner than 9.8?

The calculation method is wrong- not the "10.5 being leaner than 9.8" part.

What makes you think that calculation is wrong?

Take 85 percent times 9 for ethanol

Take 15 percent times 14.7 for gasoline

Add it together and you'll get 9.8 for E85.

Now take 30 percent times 9 for ethanol

Take 70 percent times 14.7 for gasoline

Add it up and you'll get 12.99 for E30

I see where I did wrong… thanks.