My interest in composites for my Marcos project started as a way to create a part that was too expensive to CNC machine out of aluminium. The V8 engine originally lived in a 2001 Range Rover - plenty of room under the bonnet. The Marcos is a much smaller car with a very low bonnet line. This has required a rethink on the inlet manifold design. While I can keep the cast runners, I have had to discard the single large throttle body. I will use two 48mm Jenvey throttle bodies. To mount these new throttle bodies I will need two asymmetric mini-manifold parts. Here is a rendered view of the CAD model...

You do not state the dimensions of the part, but working from the assumption that the square flange is what goes onto 48 mm throttle-bodies, I would say a way forward is to make these as "high pressure" ( sometimes called "forged") Carbon fibre .

This would be much more feasible if the flanges are at least parallel in one plane, as the image suggests.

If you already have a 3D CAD model, you could get a "negative" or male mold made by CNC machining the mold itself from Aluminium (a multi-part mold)

You would need to machine a two or three part "outside" mold and a "plug" for the hole inside.

you can then do like the watchmakers  Audemars Piguet do their "Carbon diver"     

I am currently experimenting with a variation of this technique to make Carbon "forged" rifle-scope mounts ..

So far I have made extremely strong flat and curved parts in my tests using simple aluminium moulds, made on my own lathe and mill.

Like with the watch-case, cut up or "shredded" Prepreg would probably work well.   I have used high temp and standard EC resins, with added Carbon Nanotube material from "NanoCyl" + Milled CF powder from EC and my own "cut strand" CF made from leftover cutoffs
This forms an "isotropic" "paste" that can be put in the mould.  

I heat the aluminium mould in an ordinary household oven and compress the moulds using large (M10 and M12) bolts.

This squeezes out excess resin along the joints in the mould. . I Vac-bag the whole mould before it goes in the oven.

The resulting material seems to be stronger than parts of equivalent weight parts made from aluminium, even stronger than T6 "Ergal" alloys in some of the tests.

My current problem is a high variability of the ultimate strenght, but for parts like yours, that probably will not matter. Your biggest problem will be heat tolerance and vibrations

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From your picture it dosent look undercut so I would get the "centre" of your item machined in ali or cast in resin then bolt on loose ali flanges either end

Fairly easy part that should come out rather nicw

Wow Dravis!

Just make your own pattern then.

Depending on how many you want either use your pattern to make the part or take moulds off it then cast parts from them

All this is variable on what you are going to make the finished item from ? will it see vac/temp/pressure etc

For a one off in a rush (in like the car had to leave the factory in 5 hrs !) had good results making a quick pattern in p38 !

as I'm new to all this and not sure what kind of temperatures this part is needed to whitstand, have you that about 3D printing it from some sort of ABS?

Bean Bandit, that may be a worthwhile thing to try. Maybe for the experimental stage at least. I'm wiling to try it, even if it's a non-starter, the knowledge gained could come in useful elsewhere.



Marcos Mantula blog

Why not make a loose casting pattern and get it cast in aluminium rather than CNC'd.  Waaaaay cheaper and surprisingly not too challenging to do. 

The other option would be to carve / shape it from a piece of polystyrene foam and ask the foundry to cast from that.  Its a one-shot approach but works well.

Might also be worth a chat with Boost performance as they do a lot of RV8 stuff and might have something suitable.

if its a one off and you can afford it there are suitable 3d printed materials on the market for this application, im currently working with a company over here in germany that uses a glass fibre reinforced nylon for prototype car parts for under hood applications, most of the OEMs use the parts for dyno and road testing as they are suitable for llonglife use, have a look at www.igwmbh.d
There may be something suitable in the uk too,if you ask companies like laser lines or amalglam they might be able to help.

But as f1rob says the overall pattern to make shouldnt be too difficult with a split mould and then two flanges at the end you can either bond on or create carbon flanges, i would add dome metallic bushes in the bolt holes just to be extra fancy and possibly cast a silicon mandrel of the internal shape to give you a really nice smooth surface.