[JSeery]

It depends on how the VR is mounted, if it is straight to the firewall with metal to metal contact it should be ok as is. If it has the rubber vibration washers then the ground wire needs to be connected to the firewall. I would make sure that both the VR housing and the generator are connected to a common ground near the VR and make sure that the body (firewall) has a good ground back to the battery.