This guide outlines the hardware modifications required to convert the "1980" Honda ECU board for enhanced functionality, including VTEC and Intake Air Bypass (IAB) support.

Required Components#

Components to Add#

• C60: 1uF 35V tantalum capacitor.
• D11: 600V 1A clamping diode.
• IC14: 515X High Side Switch0.
• J10: Jumper wire.
• R142: 10k Ohm resistor.
• R143: 51k Ohm resistor (recommended value).
• R144: 12k Ohm resistor (10k Ohm can be used).
• Q26: C27850 or C2458Y transistor.
• Q37: C27850 or C2458Y transistor.
• Q34: D17800.
• Q17: A1430.
• R107, R115, R116: 220 Ohm resistors.
• C94: 4.7uF tantalum electrolytic capacitor.
• J1, J3, J5: Jumper wires.

Components to Remove#

• R90
• C71
• J4
• RP17 (if applicable)

Technical Notes#

This conversion is commonly used to adapt the P75 ECU board for P72 (GSR) functionality. When performing this conversion, it is recommended to use an appropriate base map, such as a USDM GSR map with knock sensor detection disabled if a knock sensor is not present.

Always verify your board layout and component markings before soldering.