Unfortunately, I have had to change out inserts, and it either goes super smoothly or is a complete pain! The common reason I have changed out an insert is that someone has an old FC (S4/S5) Normally Aspirated rotor housing and needs to use it on a turbo- FC S4/S5/ or FD S6/S7/S8 or race engine and thus needs to get rid of the exhaust diffuser Mazda cast into the insert. Since destroyed turbo housings used to be very common the inserts were easy to get, just pull the roll pin out, heat the aluminum housing a bit, and tap it right on out, installation the reverse of removal. Nowadays wrecked housings are a bit more rare, and many of them have been recycled, so if you did have to change an insert it might be difficult. I am not sure the rational behind the Ti insert as I would think it not particularly suited to the application, but then I have not really looked into which alloy they are using and for the most part, they are being used in drag race engines that get rebuilt a tick more than often.dwalker, I've never had to exchange an Exhaust insert, is it difficult - I do like Ti. ? Pity about the cost.
It is a pity about the cost of the inconel tubing for the fabrication of a turbo manifold, and I may give in and build one, once I have the plane flying and manifold design tested and feel comfortable there will be no revisions needed. Once I have a jig built for the manifold- and that is my intent- creating a replacement becomes a matter of a few hours quality time in the shop with cutting tools and the TIG, and 321SSSCH40 pipe bends and tubing is common. I even have a buddy in the Denver area that could mass produce them in lots of 30 or 40 at a time if needed.