Flange Design

With the power plant in its final resting position, it’s about time that the Triumph gets some tunnels to spit it’s maybe-one-day exhaust flames through. Since there are no off the shelf headers that exist for my vehicle configuration, I took on the project of designing my own exhaust flange as a start to the fabrication of my exhaust system while I take a bit of a break from the tedious wiring.
As with all projects on the GT6, I’ve found myself getting lost in the world of endless possibilities and “what if’s”. I’m never truly satisfied with settling for something that simply works. I want something unique, bespoke and that speaks true to both who I am as an individual and the original intent of the car. A drawback to this consuming desire is the time that is spent thinking, researching and designing projects like these which ultimately continues to push the completion date of the vehicle further away from my grasp.
When, or even if this project ever sees the light of day, I hope to one day look back at the time spent on the unique quirks I’ve invested my time into and I say “this was all worth it”. I’m confident that this will in fact be the case, however only time can tell at this point.
So what is it then that you’re looking at? Using an el-cheapo Mastercraft caliper from Canadian Tire, I have measured the hole and slot patterns from the factory 1.6L Miata exhaust manifold gasket as the base geometry for a new high efficiency header flange. Throwing measurements into SolidWorks, my CAD suite of choice, I created a 2D sketch which turned into a 3D solid body after applying my specified material thickness.
Next comes the fun part. Wanting to extract optimal flow from my design, I created a three dimensional lofted profile which matches the exhaust ports from the head of the engine to the inner diameter of 1.5″ schedule 10 piping, a standard choice of material when fabricating custom exhaust components. This loft creates a seamless transition from one profile to the next to maximize exhaust flow by eliminating any steps or harsh transitions that would otherwise exist in conventional mass produced systems.
Once I was happy with my model, I sent a STEP file to Joe at Stim Tech for a rapid prototype of my flange. 3D printing is an incredible technology, it allows your ideas come to life right before your eyes (quite literally) and verify a design at an exceptionally low cost. To expedite the design verification process, we printed out a 2D drawing of the flange mating face and compared against the manifold gasket to ensure the measurements, and ultimately the CAD were accurate.
Within the hour, we had the design verified and the 3D model loaded into the 3D printer. The final result? A beautiful flange which mates to the engine perfectly. Now I just need someone to throw this into their CNC so I can get it made in 304 stainless. Suggestions, anyone?
One project down, a million more to go.
Stay tuned.
– Sean

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