It took me a bit to figure it out but there are some differences between the 2.85 and 1.75 versions of the titan.
here are some photos of the differences and due to the height the standard 1.75 titan will not work on the taz, so I modified a 2.85mm titan. Everything you need is in the standard 2.85mm titan kit minus the pfte tube that insulated the filament from the cold end. This pfte tube is probably common but I ordered mine from E3D along with my titan kit.
to start out the heat break is larger and uses m7 thread rather than m6 on the 2.85 version, so I drilled the heat break threads out with a 6mm drill bit, I was then able to run a m7 bottoming tap through it while constantly checking to make sure the shoulder of the heatbreak is flush with the bottom of the cold end
Now that this hole is correct the hole on the top of the cold end where the filament enters now needs to be drilled open to 4.1mm and deburred, I used the 6mm drill bit and it worked well.
Now that the modification are done it’s time to start assembling, take the pfte tubing and seat it in the heat break, then you can tread the heatbreak in (this way you’re sure the tubing is all the way seated into the heat break
you can now insert the 1.75mm guide tube that came with the titan kit on the other end of the pfte tube to measure how much needs to be trimmed off the tube
Use a razor to cut the tube straight without crushing it (the measurements E3D give for this are incorrect because we are using a different cold end) When the guide tube seats all the way on the cold end and the pfte tube is seated in the top of the guide tube the conversion is done and you can follow the rest of the instructions on the ohai site.
To help guide the filament you can use the rest of the pfte tube on the clamp above the drive gear