When you see our "estimated gains," they always represent dyno-proven, tune-only gains for that vehicle. We practice an "under-promise and over-deliver" philosophy-- in other words, we advertise conservative estimates. Gains depend on several factors: The fuel type your tune is written for (and if applicable, the fuel you're running on that tune). With Ethanol: Maximum possible gains are always achieved on an e50 or e85 tune (compatibility of stock fuel system varies by vehicle). Without Ethanol: Tunes written specifically for 93 Octane will provide greatest possible gains on pump gas. Selecting a more flexible fuel type, like "91 Octane" will not achieve the same results, even if the highest octane fuel is used. The tuning goal or other specific requests you've made for your custom tune. A RACE goal achieves max gains for your selected fuel type (100% of max gains) . A PERFORMANCE goal will provide ~90% of max gains for WHP & WTQ. A DAILY DRIVER goal will provide ~60% of max gains for WHP & WTQ. A TOW goal will provide ~40% of max WHP gains, and ~60% of WTQ gains (this is the 'odd one out' and can vary greatly depending on your specs). For DMS Tunes ONLY: A "Stock+" goal provides no change in power - this is the STOCK tune. Which modifications you have on the vehicle, if any. Again, modifications are never accounted for in our estimated gains. To read more about which modifications we recommend and why, please see Recommended Upgrades & Modifications. Please note: Fuel quality and atmospheric conditions impact gains in ways that we cannot anticipate. Running a "pump gas" with less than 10% ethanol content will produce less power than advertised. Running a "pump gas" with more than 10% ethanol can produce more power than advertised.

Is true flex fuel tuning available? No. Flex-fuel tuning is not supported on EcoBoost platforms.  Will it become available? Unfortunately, we don’t know if or when true flex fuel tuning will become available. Why isn't it supported?   The ECU does not have native support for ethanol content sensors or automatic fuel blending logic.  What if I install an ethanol sensor or gauge?  You can install an ethanol sensor to display the value on a gauge (e.g., P3 Gauge with P3ESVA and P3ESEN), but these devices do not integrate with the ECU or your tune. They are display-only. What does this mean for you? You will need to switch tunes when changing fuel types. Customers who want full ethanol coverage usually run three or more dedicated tunes:  Pump Gas: e10-e30  Options: Auto-Octane 87-93 | 91+ Octane | 93 Octane e50: e40-e60  e85: e70-e90 You can also flash back to your stock tune at any time to run 87-93 (e10). Other Considerations: 📌 For more details, see: Can I run an Ethanol Blend (E30 / E50 / E85)? ⚙️ Fuel System Requirements Most platforms can run full e85 on the stock fuel system. However, to reach your setup’s full potential, the fuel system must be properly sized for airflow and ethanol content. If the system is undersized, ethanol content may need to be reduced to stay within fuel system limits. In our tuner's words: Requires proper capacity fuel system to match the maximum airflow potential for your setup. If the fuel system is not properly sized, ethanol content may need to be reduced to match the maximum potential of your setup.

You have two options: Flash back to your stock tune (file named "RESTORE" in the TDN App, is always accessible to you) Purchase an Additional Tune - Most customers who travel often will purchase an additional tune for the Auto-Octane fuel type. Auto-Octane supports 87-93 Octane fuels, and will self-adjust for whatever is in the tank. Although you won't see the same gains as a dedicated 91 or 93 tune in terms of performance, you will maintain the other benefits of tuning such as refined throttle mapping, improved shift schedule, and increased drivability.

Fuel choice directly impacts performance, consistency, and safety — follow the guidance below for best results. Ethanol blends are a mix of pump gas (87–93) and E85. Our tunes support a range of ethanol content, with most setups performing best on a blended fuel such as E30 or E50. Running full E85 on the stock fuel system may be supported on some platforms, but blended fuels often provide more consistent performance and greater peak gains without requiring additional modifications. General Guidance: 💡 Use our Ethanol Calculator  🧪 Always test ethanol content before blending for accurate results ✅ Follow all Ethanol Best Practices ⛽️ Pump Gas Tunes / E30 (up to ~30% Ethanol Content) Support for up to E30 is included with all pump gas tunes Your tune will automatically adjust to what's in the tank: E10 → up to E30 No separate files or tuning purchases required Additional power is typically gained when running E30, even if not reflected in advertised pump gas gains 🌽⛽️ E50 (~40-60% Ethanol Content) Delivers maximum gains Compatible with the stock fuel system on most platforms (no modifications required) 🌽 E85 (~70-90% Ethanol Content) Can be run on most platforms we support Not typically the maximum output fuel type unless specifically stated or supported by upgraded fuel system components ✅ Best Practices: Flash First: Write your Ethanol tune at the pump before adding ethanol Note: While flashing issues are very uncommon and typically temporary, this approach minimizes the chance of any flashing-related interruptions. Test: Always measure ethanol content of both pump gas and E85 for accurate blending: Ethanol Calculator  Wait: After flashing and fueling: This allows fuel to fully mix and clears previous fuel from the system. Drive a minimum of 15 miles Avoid going into boost during this period