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Another RSP thread - with a twist

11780 Views 77 Replies 12 Participants Last post by  Xmedina
First time poster, spent far too long reading lots of interesting threads on intake manifolds.

However times have moved on and I thought you might be interested in my little project.

My car is an S1 elise with a K20a2, it currently has the PRB manifold and the RRC wont fit without cutting the bulkhead.

Then I discovered the RSP, not only does it look okay on paper but more importantly it is a modular design so I can take it apart to tweak quite easily.

I have seen several posts on here where people have cut the back off and welded it up and done similar to the trumpets, even seen people CNC machining new trumpets but all of that is either beyond my skill set or budget.

So this evening I set up a mini photo studio

Resulting in 109 photos of the trumpets, example below

I then imported those into 3DF Zephyr and after an hour or two of custom making image masks I was able to generate this splodge:

The rings of blue dots are the camera positions and the image mask process basically cuts out the block of wood the trumpets are balanced on. The wood is on a lazy susan (turn table) on an oversize clear plastic protractor. After each photo I rotated the part by exactly 10 degrees and took another photo, after 36 photos I rotated the part.

The splodge is a point cloud, the software has compared all of the photos an identified specific points that it can see in all (well some) of the photos and it uses these points to understand the 3d model.

Next step is to refine the point cloud:

And then generate the model

This can then be exported into your modelling software of choice. Because I am on freeware that would be Blender:

Its pretty lumpy and bumpy.

Next step is to basically trace it in the modelling software so that the whole thing is tidied up and then tweak it so it matches the dimensions of the actual part. Place particular emphasis on bolt holes etc.

I've found this to be a nice easy way to get to a 90% model that can be refined because freehand measuring things like curved surfaces can be tricky.

So why bother, where is this going?

First step will be to 3D print a new plenum back plate that does away with the resonance chamber, I can run this a while to check/prove reliability as it will be easy to see if its damaged.
Second step will be to print a set of 20mm trumpets with nice elliptical edges to open up the top end.
Third will be to experiment with different trumpet designs / angles to see if flow can be evened out / improved.
Then try and find a way to add a dual plenum to the back plate to feed the plenum.

Once the design has been tested (including dyno time) and reliability proven the last step will be printing a custom flange and runners as part of a full working printed inlet manifold to maximize.

I'm expecting all of this to take some time but i'll keep this updated if there is interest :)
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I like it. Really neat approach instead of fancy 3d scanning and proprietary software.
I have thought about that as well, in regards to TB placement. I would love to test out a blanking plate and modify the lower resonance chamber to adapt the throttle body, probably in a dual plenum design but really just looking for improved throttle body angle of attack.
drtye, you may remember the 6spd_EK RSP plenum? You find them here: (1) RBC vs RSP(euro type R) intake manifold | Page 34 | Honda / Acura K20a K24a Engine Forum . I never saw the results, I lost the contact to 6spd_EK. Maybe you have the FB contact or any other? He lives in the mountains of the sate of NY. Not to far away from your place if I am not wrong 🤔?!
Yeah, I remember that testing, can't remember if I ever saw results either... I do not have any sort of social media to speak of. NY wouldn't be too far away....
Allen socket head bolts with a tool like this might be able to reach around the bells,

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This is amazing. Bravo to you sir.
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Would this fit the bill?
Ultrasint PA6 FR (Flame Retardant) 3D Printing Material
Looks like it's melting point is 201C and flame retardant. Limited by printer bed size.
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I would 100% of the time er on the side of caution and use the inserts. With that thin of a flange it wouldn't be worth the risk even if the material was up to the load/stresses. The fasteners not being torqued enough would be moreof a concern and potentially backing out into the manifold. Even with chemical thread locker.
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