What it does
Lets the calibration use an assumed ethanol percentage without reading a physical ethanol sensor. The percentage is an input you supply, not a measurement of the fuel actually in the tank.
Choose one variant
V1 provides a fixed assumed-content table. The author describes an enabled default of 10%; changing the fixed value requires updating and flashing the calibration. On September 14 the author explicitly confirmed that V1 remains the current choice when map switching is not wanted.
V2 adds SI/map-switching selection of assumed content. This is an alternative configuration, not an instruction to install both files. Review every mode's value and the interaction with other SI-controlled features before enabling it: selecting a different mode can change the fueling assumption.
Integration and limitations
The original development was for VB and initially marked untested. Later replies include successful use and lean-running reports. An assumed percentage must match verified fuel content and a compatible base calibration; fuel trims alone do not establish that a setup is safe. This does not create sensor-based flex-fuel measurement, nor certify compatibility with an arbitrary OTS tune. Retain a known-good calibration and have the complete fueling strategy reviewed.
Credits and original discussion
Original author/contributors: michaelwrx.
https://discord.com/channels/1147002774505136228/1539462034582802432
Imported and summarized by the community site administration from the release discussion reviewed September 14, 2026. This is not a post made here by the original author. Attached files preserve the downloaded bytes; applicability must be checked against your hardware, ROM, and other enabled features.