12216125 OS Flex Fuel - Timing PE questions

[Super73]

I am looking to help a friend switch his LS based rail from a MEFI computer to an 0411 using the 12216125 OS to gain flex fuel ability.

Motor is a drive by cable 13-1cr 440" deal that is currently run on 110 octane and makes 550rwhp through the not so forgiving drive train. The car has no wide-band in it right now due to the leaded fuel and he has no way to make real tune up changes at different altitudes due to the MEFI.


I see the stoich AFR is scaled based on ethanol percentage which is what I want. The concern I have however lie in the spark corrections for E85 and Power Enrichment EQ ratio.


There seems to be only two real ways to have the ECU add timing for the alcohol:

1) Advance --> Spark Corrections --> Misc. --> Flex Fuel Spark
-- This concerns me as the dynamic cylinder airflow table only goes to .88g and I am worried it will revert back to the main table if DCA exceeds .88g. This would lead to a non-optimized timing tune up with higher ethanol content as I would have to tune for gas, specifically 91 octane (and a lot would have to be pulled).

Also, at what ethanol percentage does this come active?
Does it do any averaging based on ethanol content? IE E42 would see half of the total added timing?


2) Advance --> Spark Corrections --> AFR Correction --> Base
-- I can easily use a multiplier here in the .80 lambda column leaving .85 and up alone as I find NA E85 tune ups tend to like .77 lambda. But again, if the actual tune ends at .77 lambda, does it revert back to no multiplier?

I am thinking this might be the better section to add timing. My guess is it will average between .80 and .85 commanded lambda:
--If base was set for gas at 20* total timing (remember 13-1cr on gas and needs to be very safe)
--Commanded lambda of .80 had a multiplier of 1.5 to achieve 30*
--Then commanded lambda should look like:
.85 = 20* timing
.84 = 22* timing
.83 = 24* timing
.82 = 26* timing
.81 = 28* timing
.80 = 30* timing



In both cases I am guessing it would stick to the highest .88g for Flex Fuel Spark or lowest .80 lambda for Base but just want to confirm.







For PE, it looks like there is only a PE based on gas. This again has me concerned:

Gas tune ups seem to land in the .87 lambda range meaning a PE multiplier of 1.15 where the E85 tune up is going to need a PE multiplier of 1.30 for .77 Lambda. Sure I could keep the PE at 1.30 even on gas, it would just be rich on gas. While the car will never get beat on with Gas and will likely have at least 25% ethanol ratio, I'd prefer to have it more optimized for each blend.

If I am stuck to a fixed PE multiplier being 1.30 for E85, the more ethanol the better it will likely run



Hoping someone can help answer my questions or have an alternate route that I have not thought of.