Flex Fuel - bootmod3 CustomROM V2
- Dzenan Becic
Dynamic Stoichiometric Ratio Switch - Ethanol Sensor Based Flex Fuel
When we created the advanced port fuel injection strategies that use a DME calculated fuel mass target, such as the one described here REV2 Board: Secondary Port Fuel Injection - bootmod3 CustomROM V2 | (Advanced) MAP vs Engine RPM vs PI DI Split % Base (Gasoline) and FlexFuel (1... , we realized that we wanted a more integrated OEM-like approach with this new feature, but also for those not using secondary port fuel injection.
We feed the ethanol sensor data to the DME’s fuel mass target calculation by auto-scaling the stoichiometric ratio of the fuel based on ethanol content.
To activate Dynamic Stoichiometric Ratio functionality refer to this section: Map Editor, Tuning Suggestions, Map Configuration and Feature Activation Options - CustomROM V2 | Stoichiometric Ratio (Dynamic) Activation.
Once Dynamic Stoichiometric Ratio is activated, Fuel Scalar tables can be set to stock values instead of using values such as 1.30 to add injector duration there for high ethanol blends. They don’t require Flex Fuel blending any longer.
Static Stoichiometric Ratio Switch - Fixed Ethanol Blends per Map Slot
In addition to the above ability, we also provide means to turn off flex fuel per map slot and for those slots set a fixed stoichiometric ratio which can be used for those vehicles that may not have a bootmod3 flex fuel kit or REV2 Board on the car.
Example above shows Flex Fuel functionality deactivated for Map Slot 2 and instead using a fixed Stoichiometric Ratio of for example 9.0 for 100% ethanol. Even without Flex Fuel functionality and by using the above fixed stoichiometric value change courtesy of CustomROM V2, the engine will start in map slot 2 flawlessly on 100% ethanol without any other changes.
We strongly recommend adding a bootmod3 flex fuel kit or REV2 Board and activating the Flex Fuel functionality with Dynamic Stoichiometric Ratio Switch.
Table Blending between Gasoline and Ethanol Tables for Flex Fuel
Flex Fuel table blending is activated on a given slot using the Map Based Activation (Flex Fuel) table as described in the following section: Map Editor, Tuning Suggestions, Map Configuration and Feature Activation Options - CustomROM V2 | Map Based Activation (FlexFuel). If disabled (value for slot set to 0) on a given map slot, table blending (blend factor logic) will not be done and base table will be used at all times instead.
When enabled, Flex Fuel blending interpolates values between the Base (i.e. 0% ethanol) version of the table and the Flex Fuel (i.e. 100% ethanol) tables. Blending between the tables is done based on the set up in the respective Blend Factor table like its been done for CustomROM V1.
The following tables come with FlexFuel blend factor logic with CustomROM V2:
Boost Ceiling (1D) Map Slot 1-4 and FlexFuel
Boost Ceiling by Gear (Gear vs RPM) Map Slot 1-4 and FlexFuel
Pressure Ratio Limitation Map Slot 1-4 and FlexFuel (pressure ratio limit raised from 4.0 max, to 8.0)
Compressor Map With Required Compressor / Turbine Output Map slot 1-4 and FlexFuel (CustomROM V2 update)
Fuel Scalar Map Slot 1-4 and FlexFuel (use is no longer required if Dynamic Stoichiometric Ration Switch used)
Correction Factor Map Slot 1-4 and FlexFuel (use is no longer required if Dynamic Stoichiometric Ration Switch used)
Lambda Limit Map Slot 1-4 and FlexFuel
Lambda Target Map Slot 1-4 and FlexFuel
Ignition Timing Correction Map Slot 1-4 and Flex Fuel
Base Ignition Timing in Map Slot 1-4 and FlexFuel
Full and Partial Load
Warm and Cold operation
Maximum Relative Filling Characteristic Map (Spool) Slot 1-4 and FlexFuel
Secondary Port Fuel Injection Tables
PI IDC Load vs Engine RPM Base and FlexFuel
PI IDC MAP vs Engine RPM Base and FlexFuel
PI DI Split Load vs Engine RPM Base and FlexFuel
PI DI Split MAP vs Engine RPM Base and FlexFuel