There have been numerous conflicting statements as to where to locate the vacuum hose to go to the FPR's bleed on a S4 NA.

One stated explicitly Back of the plenum, 3rd nipple down. However, on my plenum, there is only 2 nipples on the rear - but 3 in the "front". Another stated the third from the left.

Can I just throw the hose to the FPR on the bottom nipple on the front (closest to the bumper), or must it go on the bottom nipple on the rear (closest to the firewall)?

 

Bottom front is vacuum & both on the back are as well. Or you can use the nipple under the BAC, which is the stock vacuum source for the FPR (goes to the FPR solenoid).

 

So the FPR needs to be routed to vacuum, and I can put it on either bottom front or back?

 

Yes. A vacuum source is anything behind the throttle plates. Metered air sources are those that come out before the throttle plates, and the nipples at the TB are mixed. The larger ~6mm nipple for the oil injectors is metered for example.

 

Thank you.