I had my power steering hose('93 GTS) from the pump to the rack rebuilt.
The re-builder could not re-use the metal restrictor.

What is the purpose of the restrictor and is there a reason I should not use the rebuilt hose?



When I had mine done recently, the guy at the "hose doctors" said it is to reduce vibrations and noise (its in the hose from the pump to the rack), so you are right, the same reason as the venturi in the air tubes.



I haven't got one on mine either and it has worked fine for the last 2 years.
Don't worry about it.



Without having ever seen said restrictor or knowing much about the 928's PS system, it sounds to me like it's meant to reduce the pressure from that which comes out of the pump, so I'd be worried about not installing the restrictor, and thus subjecting my rack to the full pump pressure that it wasn't designed for. (That's just Fluid Mechanics 201 talking...)



"Official reason" I read somewhere - gossip becoming gospel, is twofold - in no particular order 1 as smiffy says to reduce noise (I seem to think at full lock not moving) and 2 it's a restrictor (orifice plate) that restricts flow at higher engine (and ps pump) revs thus crudely being a form of speed sensitive power steering.

I rather have hoses that didn't leak



Some pictures of the restrictor. A good hydraulic hose repair shop can fix you a new hose :)