SDS4

Many people on this board have done so,but I heard it's bad for turbo,anyone please explain ?

DarinS4Turbo

Why would it be bad? The gauge T'd in isn't going to change the manifold pressure going to the FPR.

geoff

Tapping in there has no affect on the turbos.

<img src="http://pictureposter.audiworld.com/260/boost-guage-tap.jpg">

SDS4

My fault,maybe not the turbo,but something about causing a vacuum reservior on the FPR and run lean temporarily.

here is the tread
https://forums.audiworld.com/s4/msgs/42672.phtml

NickS

Yes because if you get a vaccum leak your car will run lean.

DarinS4Turbo

No significant effect here IMO, besides AWE recommends doing it (strange if Garrett/GIAC did not)

DarinS4Turbo

True, although if you install it correctly that shouldn't happen.

James R.

but the nipple (huh huh nipple) that feeds the FPR is pretty small, the hose going to the FPR is also very short...thus the volume is quite small, so it fills and evacuates quickly...aka it's responsive to manifold pressure and tracks it rather closely.

Now you T off of it and increase the volume of air that must be filled and evacuated by say what...I dunno that hose is 4" and most people use 6 feet or so for the boost gauge...so 18x more air volume. This is effectively a pneumatic low pass filter. You have a volume, which stores gas fed by a resistance it will have a integrating effect on the pressure in that line. The question is...is the nipple small enough (aka resistance high enough) to really matter? I dunno...but I'm not gonna chance it. Hack into something far less critical like the BPV line...of course all of my experiance is on the 1.8T tho.

Regards,

Toaster29

Why even take the chance?

geoff

You run the risk of a leak no matter where you tap into. If it happens, you'll notice it from the guage behavior.