I've uploaded these pictures a size larger, hope it looks ok.
The turbo manifold that I designed and printed failed, and I wanted to share with you guys what I think happened. I started hearing an exhaust leak about two days before I took the car to the dyno, the leak was only audible at cold start and went away as soon as everything got hot.
On the day of the dyno after the first test pull and after the car stood for a little while, while waiting on software and such, the noise was a little louder. We did one more pull and it seemed like the wastegate couldn't hold pressure for the turbo to keep boosting at high rpm so we called it, to change out the spring in the wastegate to a slightly stiffer on. We unhooked the car off the dyno and with the next start up the exhaust leak was very loud and had clearly gotten worse. I had insulated the manifold, turbo turbine housing and exhaust so seeing where it was coming from was not at easy task, however there was a hole blown through the DEI aluminum heatshield that I had over the manifold.
When I got home I let the car cool down before trying to see what damage was.
This is what I found:
And the damage was so much worse than I thought once removed:
My conclusion for why this has happened is as follows:
- 316L Stainless Steel is not the ideal choice for this kind of service, the company I used only had this option to choose from for stainless steel.
- 3D printed parts are approximately 50% less dense than the equivalent cast item and thus very porous