E85 flex-fuel remap: a fuel brief, not a checkbox on Stage 1

People treat E85 like a free octane button. It is a different fuel. More ethanol, more volume for the same energy, colder charge, a lambda the factory map never met. A Stage 1 written for 98 pump will not become a flex-fuel file because someone typed E85 in the notes. That is how you get a lean pull and a melted weekend.

The brief starts with hardware. Stock pump, stock injectors, stock fuel lines — say so. A raised pump, bigger injectors, a sensor in the line — say that too. Flex-fuel as a real blend sensor is not the same job as a fixed E85 map for a track tank that only ever sees one mix. Write which one you have.

Cold start and winter content belong on the ticket. A car that lives on E85 in July and 95 in January is two fuels. If you cannot keep the tank consistent, do not order the file that assumes it is consistent. We would rather send a 98 Stage 1 than a flex story that lies in March.

This sits next to petrol Stage 2 and Stage 3, not instead of the hardware list. Downpipe, GPF, pump, fuel. Same sentence style as every other ticket on this desk. If you are unsure the pump will hold the volume, ask on the job chat before the engineer writes a map the rail cannot feed.

Name the file. GOLF_GTI_2018_E85.bin is a brief. flexfinal.bin is a shrug. Circuit and motorsport only. An ethanol map is not a street ticket and we do not homologate the car for the public road. Keep the first dump. Petrol week will come back.