I have a personal hatred of 2 bolt flanges, but they seem to be everywhere. Inevitably they leak and people think cranking the 2 bolts tighter will stop the leak. This only makes the problem worse as it warps the flange and lets it bow out in the middle. I had this problem on my downpipe to midpipe flange that came on my car which I noticed when I was steam cleaning the engine and water was dripping out of this joint …

I just thought I would post a picture of a simple fix I did that let me keep the flange so I can maintain bolt up ease with most parts made for this car but stopped the leak cold. I cut a short piece of 3”ID SS piping and installed it as a pilot tube inside the flanges. The pipe was expanded slightly in the flange on my midpipe so it actually slid in and didn’t cause a lip to disturb the flow.

This tube keeps gaskets centered and prevents the exhaust heat from damaging the gaskets.
I actually just used a pieced of 14ga solid copper wire wrapped around the tube and high temp silicone as a temporary solution while my solid copper gaskets from summit were on back order.
My exhaust was half as loud inside the car after doing this mod. It really got rid of most of the drone in the cabin…

The blue tape is just holding some flattened welding rod in pace to keep the tube centered before I welded it in place. I am an idiot and forgot to take a pic after welding. IT looks the same but welded and no tape

Here is a pic of the flange and the gasket that has now since arrived ... The gasket is for a WRX from summit racing is anyone is interested as it took me a long time to find a 2 bolt 3in copper gasket: SCE Gaskets 9447