Je ne pige pas suffisament l'Anglais pour tout comprendre mais il me semble que çà dit qu'on peut avoir un mélange plus pauvre à l'E85 car sa combustion est plus froide.Technical facts about the mentioned fuels:
E85 requires 39% more fuel to reach stoich even if that is not what you may come up with when doing calculations based on the table below. This is because the injector flow is slightly different when using E85 among many other things I can't really think of at this time (will be added at a later time).
Fuel ........................ AFRst ........ FARst ....... Equivalence Ratio ... Lambda
Gas stoich ................ 14.7 .......... 0.068 ................ 1 ................... 1
Gas max power rich .... 12.5 .......... 0.08 ................. 1.176 .............. 0.8503
Gas max power lean .... 13.23 ........ 0.0755 .............. 1.111 ............. 0.900
E85 stoich .................. 9.765 ....... 0.10235 ............ 1 ................... 1
E85 max power rich ...... 6.975 ....... 0.1434 .............. 1.40 ............... 0.7143
E85 max power lean ..... 8.4687 ...... 0.118 ............... 1.153 .............. 0.8673
E100 stoich ................ 9.0078 ...... 0.111 ............... 1 .................... 1
E100 max power rich .... 6.429 ........ 0.155 .............. 1.4 .................. 0.714
E100 max power lean .... 7.8 .... ...... 0.128 .............. 1.15 ................ 0.870
Ethanol reaches max torque at richer mixtures than gasoline will.
The term AFRst refers to the Air Fuel Ratio under stoichiometric, or ideal air fuel ratio mixture conditions. FARst refers to the Fuel Air Ratio under stoichiometric conditions, and is simply the reciprocal of AFRst.
Equivalence Ratio is the ratio of actual Fuel Air Ratio to Stoichiometric Fuel Air Ratio; it provides an intuitive way to express richer mixtures. Lambda is the ratio of actual Air Fuel Ratio to Stoichiometric Air Fuel Ratio; it provides an intuitive way to express leanness conditions (i.e., less fuel, less rich) mixtures of fuel and air.
As you can see from the table shown above this section, the ideal target AFR´s under boost for both gasoline and E85 are listed. For gasoline it's 13.23-12.5, and for E85 it's 8.47-6.975. However, with E85 you will not need to richen the mixture under WOT/boost as far as 6.975 or beyond. It does not need to be proportionally richer when compared to gasoline.
Why? Again, Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs. And at such a low AFR as 9.765 (lambda=1 on E85) or lower the fuel cools pretty good, don’t you think so?
Many people with some experience in mapping an ECU for use with E85 says that as high AFR as 8.5 or lambda=0.80-0.85 works well. No need to go to the extreme end of the useable scale to get safe power. It only uses a lot of fuel without giving any benefits.
E85 burns faster than gasoline at best mixtures so it is an inherently more efficient fuel. It also produces more exhaust gas for a give weight of fuel air mix giving higher average cylinder pressures in spite of lower EGT's. With straight E85 in a properly tuned car its good for about +5% power / torque increase. I suspect on a turbocharged car the benefit is larger.
Since you don't have to richen the mixture as many percent (proportionally) as you have to on gasoline, you can make more power without having to use as much fuel.
Je croie aussi avoir compris qu'à richesse égale cela fait injecter plus d'E85 qu'il n'en faut, ce qui expliquerait peut être aussi pourquoi certains comme BHE évoque une conso tellement accentuée à 100% d'E85 qu'il n'y a plus d'économie financière.
Ce serait bien qu'un pro de l'anglais puisse apporter des précisions sur ce texte.
... et ce sont bien des EV6 
! sinon, ma femme vient de faire un A/R paris perpignan en roulant à 50% d'E85 avec le 4.7, et aucun problème !
? sachant qu'en gardant les injecteurs d'origine, on préserve aussi la compatibilité 100% SP ...
