My first design - throttle body adapter plate

I have completed the main body of the 3D modelling course and some of the worked examples and throughout was working on my first project on Fusion. I ended up starting again from scratch a few times as my knowledge and skills improved but now have a final prototype design. This has been a thoroughly enjoyable (although at times frustrating!) experience and I'm looking forward to bringing this design to life!

I need a custom adapter plate to fit a single plate throttle body onto a 13B-REW upper intake manifold from an FD RX-7. My throttle body is unique and so none of the existing adapters on the market would suit.

The design challenge is that the upper intake manifold (UIM) has 4 runners into 3 main ports at the throttle body flange: a primary port for the 2 primary runners and a port for each of the secondaries. I have modified my upper intake manifold to port out the secondaries into a single large elliptical port. Meanwhile, the single throttle body has a single port. So I wanted to design the internal shape so there was a nice smooth transition from the single port to the divided primary and secondary runners of the UIM.

I also wanted to incorporate grooves so that both sides of the adapter can be sealed with o-rings rather than gaskets. I am settling on 2mm cross-section metric gaskets. I was getting conflicting information on what groove is required but for a face/flange seal it looks like a need a 1.4mm deep, 2.5mm wide groove with 0.5mm radius in the corners. Please let me know if that is not correct. I will also check with the machinist when I get the product made up.

The other design challenge is that the UIM flange is not symmetrical, as I discovered when I scanned it and imported as a canvas into Fusion. Even with the high quality scan, tracing the profile and getting the sketch to become fully defined was quite a challenge, but I eventually got there and once that was done the rest of the design was easy - just a series of extrudes, fillet, holes, lofts and sweeps for the o-ring grooves.

The flange incorporates a pocket for supply air for the idle control valve. This will be covered in my application (as I can control idle via DBW), but I still needed to make sure the o-ring groove did not lie about the cavity in the UIM.

Here are some screenshots of my design (hopefully the images work)

And a shot showing the scanned canvas overlay which I used to trace the original profile. The o-ring groove looks like it work nicely.

I have printed some scale drawings onto card and it all looks like it will fit nicely. So next step is a 3D print!

I would be really grateful for any feedback on my design.

Awesome! Much of the HPA gang is at the SEMA Show this week including Connor, and working long hours covering the show. He'll likely see this next week.

Cheers!

The main outstanding concerns and potential improvements i have in my mind are:

1. The edge of the oring is only 1mm away from the edge of the primary port opening at the closest point. I can't really avoid this because of the open pocket cast into the intake manifold flange (i move the oring any further out and it will drop into that open space in the flange).

I am then left with 1mm wide, 1.4 high ridge for part of flange face. Is this going to be too thin/weak and create a stress point?

If so, i may just remove the o ring groove and stick with the factory gasket on that side (which should work just fine).

2. Whether the port openings on each flange should have a bit of a lip or chamfer into the plate before the internal transition to the other side. The way it is now may kind of leave a sharp edge around the port opening. I created the internal shape by lofting a cut between the port profiles on either side. What i could do instead is do an extrude cut (perhaps with a chamfer) around each port profile say 2mm deep and then loft between each side of the plate from the inside edge of the newly created lip (creating 2mm thickness around each port opening and adding some strength).

3. A nice rx7 logo cut into the blank face at the bottom!

Hey Greg,

Glad to hear you're enjoying the course and putting it all into action.

Awesome use of canvases and lofts!

Check out this o-ring calculator, I haven't actually used it yet (my Brother sent it to me) but it looks promising - you're right to double check with the machinist though.

https://ceetak.com/o-ring-calculator/?fbclid=IwY2xjawGXXEZleHRuA2FlbQIxMAABHTFTLCRV-G2rc5tqhg4F7rVkKhWBkPj1SbkYyIWLiKUsdemz6QqysVzaeg_aem_PXqGE3JQZ_VEqVb4MZoUng

1. It's really hard to know. I would ask the machinist if they thing it would be ok for their tooling as well.

tricky one though, and not really an obvious alternative.

2. If you modify the loft tool to use the 'tangent' or 'direction' settings does this help how the surface "flows" into the profile?