VAFC

	The Apexi V-AFC is fuel mapping controller which allows adjustment of the VTEC / MIVEC cut in point in Honda and Mitsubishi vehicles.
The latest addition to the A'PEX digital revolution line up is the V-TEC AFC. Since Honda V-TEC engines are already well tuned from the factory, extracting more power requires precise fuel enrichment and V-TEC engagement control. A'PEX introduces the world's first Digital fuel controller that allows precise fuel enrichment and V-TEC engagement control. Fuel control is adjusted by throttle position and there are even adjustment parameters available for both low and high camshaft lobes. This is what is required to change V-TEC engagement points without damaging your engine. A common misconception of a V-TEC controller is that by changing the RPM engagement point alone will result in increased performance gains. Another misconception is that increasing fuel according to RPM will result in increased performance. In reality, when you modify the V-TEC engagement point from the factory setting, the factory ECU is still on the non V-TEC fuel map. With the V-AFC, this problem is fixed by the unmatched fuel correction function. When this function is used in addition to the camshaft lobe and throttle position sensitive fuel control, the result will be a perfectly tuned engine. To ensure good results, we suggest having the V-TEC AFC tuned by a professional tuner.
VAFC Technical Features: Main Menu
Monitor Mode: Allows monitoring of up to 4 channels at one time. Also allows tracing of AVC-R monitor functions.
Setting Mode: Allows user to adjust air/fuel ratio through Wide and Narrow Throttle maps. Other features like throttle percentage settings, rpm point settings, Vtec engagement/disengagement are adjustable through the setting menu.
Etc. Mode: The etcetera menu is for adjusting the variables that are required for the V-AFC to properly adjust fuel(i.e. # of cylinders, throttle position sensor type, sensor type, etc.)
Monitor Mode: 1, 2, 3, 4 Channel	Intake Pressure Throttle Position Engine RPM Air Correction Rate ECU VTEC Solenoid output V-AFC VTEC Solenoid output

Up to four of these parameters can be monitored in three different ways:
If monitored numerically, by pressing the up key the user can see a peak hold value for the chosen parameter. If monitored in analog meter mode, up to two meters can be displayed at one time. By pressing the up key, the analog meters will hold the peak value. If under 3 or 4 channel mode, only the first two channels will be displayed. If monitored in graphic display mode, by pressing the up key the AVC-R can start "sampling" or memorizing data channels. The memorized graph can then be replayed by pressing the right key. Anytime during replay by pressing the right key again, the display can be paused. To review any part of the memorized graph, the user can push the left key during replaying. Anytime during backwards replay, the left key can be pressed to pause the display. If monitoring one channel, then the last 60 seconds can be replayed. If monitoring two channels, then the last 30 seconds can be replayed. If monitoring three channels, then the last 20 seconds can be replayed. If monitoring four channels, then the last 15 seconds can be replayed.
Monitor Mode - 2D Trace Mode
The 2D Trace Mode displays one user-selected parameter versus engine RPM. The horizontal scale being engine RPM and the vertical scale being the user-selected parameter. There are three ways to view the 2D Trace. One way is a simple cursor that floats around the screen showing what the user-selected value is. The second way to view the graph is with a 10 point floating trail to show the trend of the user-selected value. The third way is to view with a "Ghost Map" trace. The "Ghost Map" shows wherever the cursor has been and does not clear until the user clears the screen.
Setting Mode: Wide Thr / Narr. Thrtl
Both the Wide and Narrow Throttle setting maps are used for adding or subtracting fuel throughout the fuel curve. This unit takes the input pressure signal and converts this signal into absolute pressure. The modified output signal value is then converted back into a pressure signal and sent to the ECU. The Wide and Narrow Throttle setting maps can be adjusted at 16 different RPM points with 8 each on the Hi cam and Lo cam. Within each selection, Wide and Narrow, are two maps. One map is for the Lo cam and the other map for the Hi cam. This means that there are a total of 4 maps between the Wide and Narrow selections (Narrow-Lo, Narrow-Hi, Wide-Lo, Wide-Hi).
The range of fuel adjustment is +/- 50% which can be done in 1% increments. However, varying upon application, when using a stock ECU there is a limit before the check engine light will turn on. When it does turn on, this means that the ECU thinks that there is boost entering the engine and the ECU will go into a limp mode. Generally, this is in the 12-15% additional fuel range. Keep in mind that the V-AFC modifies the factory pressure sensor's signal so when a user tries to add too much fuel, the pressure sensor voltage will go too high and the ECU will think there is boost entering the engine.
When looking at the map, the vertical dotted line represents the VTEC engagement point. Fuel settings to the left side of the dotted line for Hi cam, and right side of the dotted line for the Lo cam, will have no effect on fuel correction. During tuning, the Wide Throttle map should be set first and then the Narrow Throttle map. All values between the predetermined RPM points will be interpolated. Only a professional using engine monitoring equipment should be tuning the VAFC.
Setting Mode: V/T Cont
This is the screen used to adjust the VTEC engagement point. A tuner can adjust the RPM point at which the engine switches from the Lo to Hi cam during acceleration as well as when the engine switches from the Hi to Lo cam during deceleration. However, the Hi to Lo (deceleration) rpm setting cannot be set higher than the Lo to Hi (acceleration) setting and the Lo to Hi (acceleration) rpm setting cannot be set lower than the hi to Lo (deceleration) setting. The adjustment range is between 3000 - 7000 rpm in 100 rpm increments.
Setting Mode: V/T Unmt
This function performs correction for when the ECU and the V-AFC Vtec engagement points differ. For example, if the V-AFC's Vtec engagement point is set to 5000 rpm and the ECU's enagement point is set to 5500 rpm, then the VTEC Unmatch Fuel Correction setting will occur during this 500 rpm difference (between 5000 and 5500). Technically the fuel correction can be tuned with just the wide and narrow maps, but the use of this feature allows easier and finer tuneability. Whatever values entered into this setting will be added to the corrections in the wide and narrow maps.
Setting Mode: Throttle %
On this screen there are two values, Lo and Hi. Each value determines whether the Narr.-Thr or Wide-Thr map will be used by the V-AFC for correction. If the Lo value is at 10% and the Hi value is at 50%, then the settings on the Narr.-Thr map will occur between 0 and 10% throttle position and the settings on the Wide-Thr map will occur between 50 and 100%. If the throttle is between 10 and 50%, then the V-AFC will interpolate between the two values set on the Narr.-Thr and Wide-Thr maps. The Wide-Thr value should be set at the point where air/fuel ratio no longer changes with an increase in throttle angle. For example, if at 65% throttle the air/fuel ratio is at 10.5:1 and at 100% the air/fuel ratio is 10.5:1, but at 55% throttle angle the air/fuel ratio is 10.9:1 then the setting for Wide-Thr should be 65% (the point where air/fuel ratios no longer vary according to throttle angle).
Setting Mode: Ne-P:Hvt
This menu allows adjustment of engine RPM points to control fuel while the engine is on the Hi cam. The user can define eight points between 3000 and 9000 rpm in 100-rpm increments. These eight points will appear on the Hi cam maps in both Narrow and Wide setting screens.
Etc. Mode: Sensor Type
This menu allows the user to select which type of sensor the V-AFC will be correcting. All Honda models will be set to 06 IN and 06 OUT
Etc. Mode: Car Select
This screen allows the user to set the number of cylinders the engine has and what type of throttle position sensor the engine uses. All Hondas use an ascending type (arrow pointing to the upper right hand corner) throttle position sensor.
Etc. Mode: Grph Scale
This mode allows the setting of the maximum and minimum values to be displayed under the Monitor Mode's graph display mode, analog meter mode, and 2D Trace mode. The user can select the following scales:
Pr: Intake Pressure	-760mmHg~0mmHg -760mmHg~+1.0kg/cm2 -760mmHg~+2.0kg/cm2
Ne: Engine RPM	0rpm~6000rpm 0rpm~7000rpm 0rpm~8000rpm 0rpm~9000rpm 0rpm~10000rpm
Cr: Air Flow % Correction	+/- 3% +/- 6% +/- 9% +/- 15% +/- 30%
Etc. Mode (sensor check) This mode will check the voltage of the pressure sensor, throttle sensor, and scramble switch on/off. This is to check if all connections have been properly connected after installation. Also if there is improper operation, this screen can be viewed to determine if any connections or sensors are bad.
Etc. Mode (VFD bright) This mode allows brightness adjustment of the VFD (Vacuum Florescent Display).
Etc. Mode (Initialize) This will restore all data to factory default settings. All previously saved data will be lost. To initialize data, select YES and push the [NEXT] key. Then turn the ignition switch OFF and then ON again. All data will be initialized.