Tuning on ethanol

[ayau]

I'm currently running the E25 base map and am curious about running more ethanol. Based on the flex table compensation multiplier, E40 has max ignition. Higher than E40, the boost by ethanol table will just reduce the air charge limits. Is it safe to assume the car's sweet spot is E40 (considering factory fuel pump limitation)?

I did a ignition table comparison between E40 and E25. This shows either ignition advance (green) or ignition retard (red). See attached screenshot.

For learning purposes (not sure if I'll actually do this), would I be able to essentially run the same E40 ignition table as long as I do the following?
1. Run fuel tank low, add E40
2. Copy E40 ignition table to my custom tune table
3. Copy boost by E40 ethanol air charge table to my custom tune
4. Add 24% fuel trim to my custom tune
5. Log to ensure data looks good

[ttking885]

I dont see a log posted. do you have a 3rd or 4th gear pull to share?

[ayau]

I dont see a log posted. do you have a 3rd or 4th gear pull to share?

I haven't done too much. I've only tested with E30 without changing anything in the calibration. Fuel trims still look pretty decent. Here's a 4th gear pull.

I noticed long term trims are -3. You'd think that if I'm running on the E25 calibration, the fuel trims would be positive since there's more ethanol.

I most likely won't mess with the ignition tables as I don't have a full understanding of the various tables. In theory, higher ethanol would mean the engine should be even more knock resistant though.

[ttking885]

thanks, yeah im 25 psi, e50 and running the same timing.