Guessing or using incorrect injector characterization data will result in poor performance and potentially engine damaging situations!
For consistency and ease of use we’ve used the same fuel injector characterization method as MHD+ Advanced Reflex Port Injection (ECUTEK/COBB GTR characterization). In addition we have kept all table names and units identical so tuners already familiar with this process will be able to get up and running quickly. For this reason we recommend you familiarize yourself with the below tables on page 29 of the MHD+ Suite Tuning Guide.
Fuel Injector & Pressure Tables
Base Fuel Pressure
Injector Scalar
3D Injector Latency
Differential Fuel Pressure Compensation
Non-Linear Injector Compensation
Non-Linear Injector Compensation Maximum IPW
These tables are located in MHD+ Suite → NXM Port Injection. Populate these tables with the base fuel pressure and injector characterization data from the fuel injector manufacture.
Once all Port Injection tables are populated you can enable our custom code by setting Enable Nexsys Motorsport PI Conversion to 1.
Differential Fuel Pressure Compensation table should be filled with 100% if using a 1:1 boost referenced fuel pressure regulator.
MHD’s PI Safety MUST be disabled in flash-time options before flashing the vehicle. Failure to do so will result in pops/bangs on throttle lift that can cause engine, turbo and exhaust damage.
Other table recommendations
Latest EOI Angle - Set to 0*. This will allow you to use the entire injection window.
Minimum LPFP Pressure - Set to 10-15 psi below your base fuel pressure. This will keep limp mode from occurring at lower fuel pressures.
Enable LTFT - Set to 0 during the fuel tuning process. This will disable long term fuel trims temporarily while fueling is tuned. On single bank vehicles it may be beneficial to have long term fuel trims always disabled.
Fuel Reactivation Adder - Set the entire table to 6.0. This will help prevent the engine from wanting to stumble when exiting fuel cutoff.
Fuel Target Adder (Warmup) - You can use our base values below. This table is added to the AFR Target table Fuel (Main). This table allows negative values so it provides a nice method for allowing a richer AFR target during engine startup and warmup which is needed for port injection vehicles. These values may be able to be reduced, this is simply a starting point.
Fuel Target Adder (Cat Heating) - You can use our base values below. This table is identical to the one above but is used when cat heating is active. Modifying this table is important as in stock form this table will cause the AFR target to be too lean for port injection.
