BACK.
Big update: The k04 is in the car and all works fantastic. From this point backwards, there were a bunch of considerations and contingencies for me to deal with in the installation. I won't go into those details here because they're a system problem and don't necessarily concern the rebuild process itself. I would definitely recommend giving the install threads a good going-over before trying to tackle any used k04 buy and/or install.
Next are my notes about the rebuild process.
Getting the CHRA onto the compressor housing is just like taking it off. Fitment is tight, so a rubber or plastic mallet and some thorough light tapping is required to get it back on. The v-band does most of the work getting the CHRA into place. There is a strict orientation, but the parts are keyed so you can't get this wrong. There are no gaskets or o-rings to consider here.
Next is getting the compressor housing onto the CHRA. The parts are joined by a number of small 10mm bolts and washers. There are 4 bolts on the k04 housing and 5 on the k03, though they're different bolts so they don't carry over from one to another. Take care getting these parts together - the compressor wheel sits VERY VERY close to the compressor housing and you really don't want to scratch the two together for risk of making a barb or fissure that causes compressor wheel to compressor housing contact. Two things here: 1) tighten the bolts gradually and evenly to pull the compressor housing to the CHRA, and 2) make sure throughout the process that the turbine wheel can spin freely, ensuring that nothing is coming in contact with either wheel.
This is the best picture I have to demonstrate how the compressor housing mates to the CHRA. Look at the k03 on the right. Note the aluminum plate is a part of the CHRA assembly, while the bolts mount to the compressor housing.
There is a gasket needed here keeping the compressor housing and CHRA connection air-tight. I got an o-ring with my blown k04 purchase (CTS probably shipped it to my seller along with the bolts needed to mate the compressor housing to the CHRA), but I noted that the stock k03 used a liquid sealant from the factory. I gather that a good liquid gasket would probably do the trick great, if not over-applied. First picture is the remains of the gasket on the k03. Second is the o-ring I received with the CTS pseudo-kit.
Lastly, the "OEM" liquid gasket:
Orientation of the compressor housing to the CHRA matters. The first thing you'll find on the bench is the wastegate mounting bracket must line up. That's fairly self-evident. Otherwise, if the compressor inlet pipe is too forward (towards the manifold) then it will come in contact with the coolant return hard-piping as the whole assembly is mated to the block. If it's too far back, you'll have intake fitment issues and, at worst, you'll be hitting some other equipment bolted to the firewall. My recommendation here is to mount the compressor housing to the CHRA and then test-fit the whole assembly with those lines attached to the block (they're moved out of the way during turbo removal). Don't worry about the heat shield, it's not going to interfere with the compressor housing. Re-clock if necessary.
I didn't do this. I lucked out, although just barely. If my intake (a VF Engineering unit) wasn't much smaller in diameter than the intake coupler of the DV relocate kit I bought, I would have had to remove the turbo and re-clock the compressor housing (good thing I used the o-ring, because if I had applied the liquid gasket I'd have to carefully scrape it off and re-apply). As it is, the intake coupler rubs lightly against the coolant return line and doesn't bother me too much. I may try to re-clock it some day, if it can be done while mounted to the car. I'm not too sure if it can.
All things considered, the hardware all works properly in application and the tune seems to run it great. Check out my build thread (
starting page 20) for a log of my install shenanigans and, in the following 3 pages, my impressions of k04 in general.
