Audi S1 quattro
inlet manifold

The client came to us wanting to create a bespoke inlet manifold for his Quattro S1 replica. He already had the CNC’d head flange in-hand, but wanted to know what his options were for the rest of the manifold.  The original design intent was to utilise off-the-shelf extruded runners & inlet trumpets, with sheet metal being used to fabricate the rest of the manifold:

1x CNC machined head flange to suit Audi AAN/ABY/7A cylinder head inlet ports

5x Ross Machine Racing extruded runners

5x Ross Machine Racing CNC machined inler trumpets

In addition to the above, a plenum baseplate with 5x 3″ holes would need to be cut & have the machined inlet trumpets welded in place.

The flange was already in-hand & of reasonably sound design, so the main focus of our work here was to

1) Reduce the amount of fabrication time required 2) Reduce manifold sub-component cost

What we came up with was a a cost vs performance compromise. The plenum baseplate was optimised to be cut from a standard 4″ x 3/4″ 6082 T6 aluminium billet.  This kept machining time & material wastage to a minimum, but limited the possible inlet port radius.  Using one of our trusted suppliers, the part cost for this came in below the import cost of 5 x inlet trumpets from the USA.

Initial welding of machined parts

Finished manifold installed in engine bay

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