About the HKS GCC:
The GCC is an electronic tuning component designed to add additional flexibility to the fuel tuning capabilities of the VPC, PFC F-CON or F-CON S. The GCC simply plugs into either the VPC or F-CON harness and allows the user to further adjust the air / fuel ratio at five specific rpm points. Each five points offer an adjustment range of 16% rich to 12% lean, in 2% increments, of the base value. Four different selectable rpm ranges allow maximum rpm level flexibility when tuning the fuel curve. The GCC will interpolate, or average between the rpm points of adjustment to ensure a smooth transition of fuel delivery throughout the RPM band
and the IPM:
The HKS Injection Pulse Monitor, or IPM, is an electronic injector duty cycle monitor and display unit. When tuning a fuel system with an HKS Graphic Control Computer (GCC), VPC, F-CON, AIC III or Super AFR, the IPM is essential for determining the remaining fuel injector capacity. With the supplied wiring harness, the IPM plugs directly into any vehicle equipped with an HKS PFC F-CON (Programmed Fuel Computer) or can be wired directly into the stock ECU harness of any electronically fuel injected application. When used with the PFC F-CON, the IPM will show the difference between the factory specified pulse width vs. that of the HKS F-CON pulse width on its dual level LED display. When used with the stock ECU, two separate injector signals can be displayed on the dual level LED display, either two stock injector signals or one stock injector signal and one signal from an AIC injector. As the injector pulse is increased via fuel controllers, the IPM will display the new injector duty cycle in real-time. In addition to monitoring, the IPM incorporates an audible alarm that can be set to trigger when any pulse width from 50% to 95%, in 5% intervals, is reached