Could be wrong, but I dont think its possible on a B18C engine, on a B16A2 (OBD1) u can go backwards cuz theres an OBD0 version of a B16 (B16A1), but the B18C dosnt have a version to go back too... I *think* u can make it OBD1 which is easier than switching to OBD2... But its still no walk in the park...