I'm overhauling my fuel system. Got a a1000 fpr and everything stainless braid with new fuel rails. All I could find was the factory fuel pressure for FD's. Whats the S5 turbo stock fuel pressure?

-also does it make a difference if the fuel goes filter>primary>secondary>fpr>return OR filter>Y-fitting>both rails>both fpr inlets>return???

 

The fuel line pressure (34.1 - 39.8 psi) is listed in the factory service manual. The FAQ sticky has a link to online versions of the manual.

Running the fuel lines in parallel is usually better for high-output applications with a standalone EMS, but for a mostly stock setup I don't think it makes any difference whether they are in parallel or series.

Article from Kinsler:
http://www.kinsler.com/Cat_31_High_R..._press0071.pdf

Here is a parallel fuel diagram made by RETed. It is for the S4 RX-7, but it gives you the main idea.

 

Thanks for the detailed response. In that case I'll run my y-fitting in a parallel setup since I have a power FC and upgrading the turbo in the near future.