[CigaR007]

I did some preliminary testing yesterday and the floor register opening is not effective. Coolant kept creeping up to 204F until the fan turns on.

On the way back home, I removed it, while keeping the foam casing, and the coolant temperature was rock solid at 188F. That can only be explained by a more stable air flow.

I have a feeling that the opening angle of the floor register is too sharp and the incoming air becomes too turbulent, thus affecting its cooling capability.

I am now considering just keeping the foam casing in place (better aero, efficient cooling) for the winter.

I guess I have some more thinking and tinkering to do.