djessence

Good Day everyone,

I've been through a bunch of the vacuum hose and emissions removal threads as well as the vacuum hose routing diagrams, but can't see these ones on them. The car background is it's an S5 engine going into an '83 GSL racecar (no emissions, very few electronics)


Dead center on Lower Intake Air Manifold - had a little goose neck hose on it - can't see where it may have gone on the Upper intake manifold and emissions are being removed - what did this go to? And if emissions are removed, is it still required or should it be capped?

The second is (I think) on the upper intake manifold and has a little inline check valve (I think) going to the back of the UIM shown below - what is this for? Where should it go?


Any guidance is much appreciated. Unfortunately a bunch of the vacuum hose and emissions threads I have been reading no longer have images.

Thanks!

professionalpyroman

On the S5 Turbo, the hose in the center of the lower manifold is routed up to plug in to the back of the upper manifold, to draw a small amount of air around the throttle body for idling and to allow the throttle body to be set correctly. Under driving conditions, it does practically nothing. I would expect similar for this engine.

On the S5 turbo, we only have 1 of those check valves that I know of, and it goes from the back of the intake to the thermowax plug on the throttle body to hold vacuum on the diaphragm and prevent the secondary throttle plates from opening when engine is still cold. See page F1-38 in the FSM for more details on your engine.

djessence

Thanks - this is helpful!