I'm looking for some general advice on making an intake plenum to suit a low boost turbo engine (7 PSI) out of carbon fiber using vacuum infusion, utilising my 3D printer to create the mould. This would be the first carbon fibre part that I've made, based on a design drawn up in Autodesk Fusion 360 shown below.

So far I've spent a few days doing research online, reading other posts in this forum relating to intake manifolds and 3D printing moulds and watched numerous videos on producing carbon fibre parts. However I still have a few open points I'd like to get peoples opinion on. 

• Based on the plenum shape I'm assuming I would create a positive mould.
• Should I use tooling gel or something like 3M Super 77 sparingly to ensure the CF attaches to the shape.  
  
• Does this sound right to create a 3D printed mould; use PLA filament, smooth down the edges, spray a few coats of plastic filler primer and seal with S120 mould sealer.
• For the 4 bolt end flange I'm guessing this can't really be formed using CF. Instead could I go about inserting an aluminium flange that could form part of the mould and be covered in CF. Would this hold up under boost? 
• Layer up wall thickness to be around 2mm, from what I've read this would be strong enough.

I do believe you that it happend. But it was likely a construction problem. Wrong shape or insufficient wall thickness. Maybe insufficient overlapping of the layers of a two part mold.

As long as we are not talking about aerodynamics, intake plenums are really not that much of a challenge for experienced laminators. The second half of the sentence is quite important though.