All i can tell you is that when i tune my honda on e-85 i tune to 7.7 air fuel or about .8 lambda but this is a different car it is not a DSM it is a B16 with only 10psi of boost.
All i can tell you is that i tuned in Lambda to try and not have the air fuel ratio issue
Converting to E85 (ethanol fuel) - Turbobricks Forums
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
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.
When driving purely on E85 you can blend it with up to 25% gasoline in case you want to raise the AFR number used to produce max. power. In that case you can raise the boost even further since the volume of fuel needed to reach the desired lambda is decreased.
Performance application and fuel needed:
Performance application:
Let´s pretend for a while that the ECU´s in our cars are pretty good at their jobs. On gasoline it will try to keep an AFR of 14.7 (lambda=1) all the time at idle, cruise and light load. It will also try to keep a good AFR at WOT/boost of 13.2-12.5, sometimes even lower than that, probably closer to 11.x.
Why? Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs.
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.
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. Instead you can keep the AFR´s leaner across the board and by doing so you can make room for higher boost without maxing out the injectors.
Fuel needed:
As you will see, both in my article as well as other places on the internet, different fuel requirements are listed. What numbers will you see and why?
1. A car converted, but not specifically mapped for E85 will consume ~30% more fuel.
2. A car running E85 will require ~42% more fuel.
3. According to your own calculations (if you have bothered to look in to it), it will not quite add up. Most people scratch their head.
Let me show you a table again:
Mode ........... Gas .... E85 ...... extra % (mass) ... extra % (flow)
Stoich .......... 14.7 .... 9.765 ........ +50.5% ................ +42%
Lean power ... 13.2 .... 8.47 .......... +55.8% ................ +47%
Rich power .... 12.5 .... 6.975 ........ +79.2% ................ +69%
E85 has a higher density than gasoline. The change in AFR from 14.7 (lambda=1 for gasoline) to 9.765 (lambda=1 for E85) is 50.5%. But the resulting flow needed is only 42% greater.
Explanations to this: E85 will need a fuel flow that is 42% greater than the flow needed for gasoline. However, it will not use 42% more fuel since it will actually be more efficient. Generally, the engine will consume ~30% more fuel.
If I am using 46.7lb/hr injectors (45% larger than stock) which are easy to get hold of, my AFR´s should theoretically look like this:
*At idle, cruise and low load (closed loop) the AFR will be 9.56, the O2-sensor sees this and will correct it to 9.765. A very small correction, and it lies well within the adaptation limits. Not even noticeable as more than normal adaptation by the ECU.
*When at WOT/boost (open loop) the AFR will be between 8.58-8.13. This looks a little lean according to the AFR table, doesn´t it? It isn´t even in the "rich" area according to the table. No worries, the cooling properties of E85 are pretty good. But in reality I will actually get an AFR of around 8-7.5 since my ECU wants to run a slightly richer mixture than 12.5 on gasoline. It obviously does not know that it is running E85...
EDIT:// I am now running 75lb/hr injectors and 3" AMM. This is to meet my performance goals of 300HP+.
. I would like to play with it, but I don't know of anyone in my area running e85 just yet, other than the v8 crowd.
