I'm missing something in this calculation somewhere.
It's said that going from gasoline to E98 (98% ethanol) is a 37.5% increase in fuel flow to maintain the same lambda. This is proven with datalogs repeatedly. However, let's say we have an engine consuming 50 lbs/min of air (~620 CFM) based on given VE and assuming perfect sea level air. E98 has a stoich air/fuel ratio of 9.01:1 while ethanol free gasoline is 14.7:1.
50 / 14.7 = 3.40 lbs/min of fuel with gasoline
50 / 9.01 = 5.55 lbs/min of fuel with E98
5.55 / 3.40 = 63.2% increase in fuel flow by weight
Even factoring in flow by volume with E98 at .790 SpG (6.59 lbs/gal) and gasoline at .745 SpG (6.21 lbs/gal)...
3.40 / 6.21 = 0.5475 gal/min
5.55 / 6.59 = 0.8422 gal/min
0.8422 / 0.5475 = 53.8% increase in fuel flow by volume
What am I missing here?
It's said that going from gasoline to E98 (98% ethanol) is a 37.5% increase in fuel flow to maintain the same lambda. This is proven with datalogs repeatedly. However, let's say we have an engine consuming 50 lbs/min of air (~620 CFM) based on given VE and assuming perfect sea level air. E98 has a stoich air/fuel ratio of 9.01:1 while ethanol free gasoline is 14.7:1.
50 / 14.7 = 3.40 lbs/min of fuel with gasoline
50 / 9.01 = 5.55 lbs/min of fuel with E98
5.55 / 3.40 = 63.2% increase in fuel flow by weight
Even factoring in flow by volume with E98 at .790 SpG (6.59 lbs/gal) and gasoline at .745 SpG (6.21 lbs/gal)...
3.40 / 6.21 = 0.5475 gal/min
5.55 / 6.59 = 0.8422 gal/min
0.8422 / 0.5475 = 53.8% increase in fuel flow by volume
What am I missing here?