Apexi Logo

AFC Air Flow Converter

Click here to buy SAFC Neo!

How does the AFC Air Flow Converter Work?

The A'PEXi Air Flow Converters work by intercepting the signal between the car's air flow meter and the ECU. The Air Flow Meter is the device that tells the ECU how much air is entering the engine so that the ECU can add the correct amount of fuel.

The ECU calculates the proper ratio of fuel to air for a stock, unmodified engine. Certain engine modifications can cause the dynamics of the engine to require more fuel. In this case, there are two common options for modifying the amout of fuel being input into the engine. One can either install larger injectors or increase the fuel pressure to the stock injectors is increased.

Since the stock ECU thinks that it knows how much fuel it is putting into the engine based on the stock injector size and the stock fuel pressure, changing either of these will result in increased fuel. You may get lucky and just pick the perfect injector or fuel pressure that gives you the perfect air/fuel ratio. You may also get lucky and pick this weekends winning lottery numbers. In either case I wouldn't bet the farm on it. The Air Flow Converter gives you the means to adjust the amount of fuel that the ECU injects into the engine by modifying the signal from the air flow meter. This is done a specific RPM levels. This way you can tell the engine that a certain amount more air is flowing into the engine as a specific RPM than is really entering the engine, and the ECU will add that much more fuel. Decrease it at another RPM level and the ECU will decrease the fuel into the engine.

What cars can use the AFC Air Flow Converter?

In general, any Japanese-made car with factory fuel injection and a mass air flow meter. However, these have been adapted to work with many other cars made in Korea, the USA, and Europe. It all boils down to identifying the correct wire into the ECU. In general, the following wires must be identified:

Fortunately, in many cases these wiring diagrams are available in the A'PEXi Vehicle-Specific Wiring Diagrams. If your car is not found here, you can often do a Google search for your model name and "APEXI SAFC" and find the fruit of someone elses labors lovingly presented in an online forum.

Which SAFC that is right for you?

Current Model


SAFC NEO - The SAFC NEO marks the newest edition to the world famous Super AFC line of piggy back fuel controllers. Building upon the powerful SAFC II, the AFC NEO has taken piggy back style fuel control to a new level. (More...)

Legacy Models (No Longer Available)

Apexi V-AFC II

V-AFC II - Like the Super AFC II, the VAFC II displays data in three different modes: Numerical, analog, and graph. The V-AFC II adds VTEC-compliant engagement control from 3000-7000 RPM in 100 RPM increments. DISCONTINUED!

Apexi S-AFC II

S-AFC II - The Super AFC II (Air Flow Converter) is the industry standard for sub computer fuel control. The S-AFC II is designed to fine tune and "squeeze" power out of existing engine setups by allowing the user to modify the fuel curve with precision accuracy. DISCONTINUED!

Apexi S-AFC Select

S-AFC Select - We are pleased to announce that the industry standard S-AFC II fuel computer can now be enjoyed by European car enthusiasts! DISCONTINUED!


Apexi SAFC NEO Image 1
Apexi SAFC NEO Image 2

The SAFC NEO marks the newest edition to the world famous Super AFC line of piggy back fuel controllers. Building upon the powerful SAFC II, the AFC NEO has taken piggy back style fuel control to a new level. The AFC NEO boasts an incredible 16 points of user definable fuel correction. VTEC control has also been incorporated for Honda/Acura applications. (Cannot control valve timing in i-VTEC engines, but still provides user-definable fuel correction to the i-VTEC motor.) A complete monitor mode is also available to keep the driver/tune informed of critical engine data.

Features include:

  • Completely new case design
  • Compact design
  • Incorporates both AFC and VAFC functions in one unit
  • 16 point fuel correction
  • Color FED display
  • User defined button and background colors
  • Inverted "anti-glare" screen

Key functions include:


  • RPM
  • Throttle
  • Battery voltage
  • Correction %
  • Air flow %
  • Pressure
  • Karmann
  • VTEC


  • Air map
  • Air map graph
  • Throttle point
  • Deceleration air
  • VTEC control
  • VTEC unmatch


  • Model select
  • Mode select
  • Car select
  • Sensor select
  • Analog scale
  • Warning set
  • Display set
  • Sensor check

Orders over $150 ship FREE!

Part # APEXi Product Price  
401-A018 NEW AFC Neo $434.50 +
Free Shipping!

Don't see what you're looking for?