How do you set up flex fuel so the car adjusts commanded lambda between E85 and pump gas?
Here is what the documentation says. Each point links to its source; tables and names vary by computer, operating system and tuning software.
- E85's lower energy density requires 30–40% more fuel-system flow to maintain the same lambda, so fuel-system upgrades and tuning go together. (Performance Racing Industry)
- A flex-fuel tune also lets the engine run on regular unleaded gasoline when E85 is unavailable or before storage. (Performance Racing Industry)
- A flex-fuel tune requires an ethanol-content sensor in the fuel system communicating with the ECU so the engine adapts to varying ethanol concentrations. (Performance Racing Industry)
More in fuel, E85 & boost, or build a checklist for your swap with the tune checklist tool.
Confidence: medium — sources disagree or are limited; check the sources below.
Community discussion
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Sources
- PRI Education: Converting From Pump Gas to E85 — Performance Racing Industry