[lee88]

I have a '77 ROW (German delivered) 930, indeed no thermal reactors.

My understanding from the Snodgrass 3.0 Turbo book is that there were three components to the system to comply with North America (possibly also Japan) emissions regs: the exhaust gas recirculation (EGR) system, the secondary air injection pump, and then the thermal reactors. I believe the first two were fitted to all cars and in fact after they designed the system Porsche engineers discovered the secondary air pump actually improved boost pressure and torque slightly <3K RPM. The thermal reactors were fitted for US cars but not ROW.

So would make sense for the SAI pump and EGR to be in place but the thermal reactors definitely wouldn't be. Also as you probably know the exhaust routing is slightly different in the ROW cars because of the lack of thermal reactors. The heat exchangers are different since there's no outlet for thermal reactors and there's a cross pipe that routes exhaust to the wastegate & turbo.