Apexi 401-A917 AFC-neo. The AFC-neo is a multifunctional sub-computer that allows the tuner to fine-tune air-fuel ratios, calculate MAF/MAP transfer functions, control VTEC or other solenoids, address stall issues associated with open-air blow off valves, and monitor key ECU data.

Changes in air-fuel ratio are achieved by correcting the airflow sensor signal or pressure sensor signal at 16 different RPM points, and at high and low throttle positions, all of which can be moved according to the customers needs. By changing this input signal, the tuner can alter the injector pulse width as calculated by the ECU.

The AFC NEO is unique in the sense that it has a built in MAF/MAP transfer function, which is necessary when the tuner swaps MAF/MAP sensors from one vehicle application to another. By setting the sensor IN and OUT to the appropriate sensor numbers, the AFC NEO can act as a translator/emulator unit, eliminating the need for costly sensor or ECU reprogramming.

The unit also has a VTEC solenoid control function that allows the tuner to change the VTEC engagement/disengagement point on Honda VTEC systems (not compatible with iVTEC systems). The VTEC solenoid control and also be used to control other types of solenoids as used in nitrous-oxide and water/methanol injection systems.

On MAF applications with open-air blowoff valves, there is a deceleration air correction feature that allows the tuner to compensate for the over-rich condition that occurs at throttle-off. By adjusting the MAF signal at throttle-off condition, the tuner can reduce the amount of fuel injected and prevent stalling.

In monitor mode, the driver can monitor digital engine RPM, throttle position, battery voltage, airflow sensor capacity usage, pressure sensor data, Karman frequency, MAF/MAP/Karman correction factor, and solenoid on/off status.

The AFC NEO is a universal unit that can be used on a wide range of cars and trucks that have an air metering system that uses a VAF, MAF or MAP sensors operating within the 0-5 volt range, as well as applications using Karman sensors. There are some unique applications that do not allow for the proper functioning of the AFC NEO.