E85 Tuning Method

[Asteroid]

I want to convert to E85 on my NA 442cid LS jet boat engine. I'm using an F-body 411 PCM. My plan is to change the scoich value to 9.7 and use EQ ratio (power enrichment) of 1.2 to set WOT at 8.08 afr (.83 lambda). I have purchased an AEM E85 gauge and WB which reads out in afr. It also has an analog output that I assume provides 0 -5V lambda data which I will record on my HP scanner. I'm thinking that the scanner will translate the data into afr gas values. What do I need to do to adjust the scanner to display 'lambda' or E85 afr values?

This engine has a very good SD tune for gas (VE tables are accurate) and I just want to convert to E85. Is this the proper approach or is there a better method to use?

THX
Asteroid

[LSxpwrdZ]

Make sure you have plenty of injector for the switch. Fuel demands are quite a bit more on e85 than gas.

[Iam Broke]

I went up to 42# Bosch greenies (~50 lb/hr at 58 psi) on a mild build LS1 and see ~85-90 IDC at times on full E85 on about the same PE as you are talking about.

I think you'll need around 60 lb/hr at your fuel pressure.

Another alternative is to run 1:1 E85 and 93 (E47) for the ethanol advantages. It needs around 15% more fuel where E85 needs ~30% more but the mixing is another issue.

[Asteroid]

Yes, I have Siemens 60# injectors (69@58), dual fuel pumps and large lines. My main question is; Will changing the stoich to 9.7 and power enrichment to 1.2 get me in a safe ballpark with my SD tune? I can refine the tune once it is running safely.
Asteriod

[Iam Broke]

Should be ok if you are close now, I think I had to drop to 9.62 stoich or it rounded up to 9.77 in the ecu. Better safe than sorry. I don't have the tune here to check the exact numbers though.

.8333 lambda (1.2 PE) is close to max power lean on E85 (.85) If in doubt richen up the PE a bit when you start tuning.