Initial Configuration

Owned by Austin Vann
Last updated: Sept 20, 2024
1 min read

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

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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.

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.

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  • 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.

  • After Start Enrichment (ECT) - You can use our base values below. This table allows the tuner to adjust relative fuel mass after the engine has started for a certain duration of engine cycles.

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