It is the brake booster vacuum line. Period.
On the Tiptronic cars, it connects to the right rear of the engine via the venturi tube.
On the manual transmission cars, it connects to the left front of the engine.
Part number 986.355.575.05 or 986.355.575.0
6. I'm not sure what the difference is between the two. I bet a
phone call to Pelican Parts or Woody could get you the right part.
Here's where the Vacuum line connects on the manual cars:
Parts 3, 23, 24 connect the vacuum line.
Here's the vacuum line:
#14 - The elbow attaches to this on the manual cars. The venturi hose attaches to this on the Tiptronics.
I learned all this a few years ago when I swapped a manual engine into a Tiptronic car.
