You completely right. E85 has much less energy density than gasoline. I found a nice
table on Wikipedia listing a comparison between Gas, E85 and 100% ethanol:
Gasoline stoichiometric AFR = 14.7 Lambda = 1
Gasoline max power rich AFR = 12.5 Lambda = 0.8503
Gasoline max power lean AFR = 13.23 Lambda = 0.900
E10 stoichiometric AFR = 14.0-14.1 Lambda = 1
E85 stoichiometric AFR = 9.765 Lambda = 1
E85 max power rich AFR = 6.975 Lambda = 0.7143
E85 max power lean AFR = 8.4687 Lambda = 0.8673
E100 stoichiometric AFR = 9.0078 Lambda = 1
E100 max power rich AFR = 6.429 Lambda = 0.714
E100 max power lean AFR = 7.8 Lambda = 0.870
Something else that goes hand in hand with this is the Stoichiometry of Regular E10 fuel used in California.
I have 740cc injectors. My car likes my injector flow scaling to be set about 5% lower than the actual flow (Flow Scaler = 703cc/min, Actual Flow = 740cc/min), which lines up pretty close to the difference between pure gas and E10. I don't know if this is the proper way of handling this, but it seem to work pretty well.