I'm rebuilding my S5 stock turbo and am planning to use a -4AN feed from the oil filter pedestal. I've seen references that rebuilt or modified turbos need a restrictor. I have the turbo apart but don't see what difference between the new and old parts could make. Do I need one?

 

i was asking hte same question and had no replies too. The restrictors are usually for ball bearing turbos. But my engine has higher than normal oil pressure, and I used to have oil burning issues with my turbo.

I made my own restricto ouit of a thin piece of alluminum the same size of the flange. I forgot the size of the hole

 

The stock turbo has an internal restrictor.

The GT series turbos have an internal restrictor as well but many people run an external 0.030" restrictor as well.

 

ahhhhh, gracias