The smaller Mitsubishi turbos - 14b, 16g, etc, all have compressor housings that point in the same direction - roughly up and forward, in our cars. With most turbos - larger Mitsubishi Turbos (20g, etc), Garrets, etc - the relation of the three parts of the turbo is nonfixed. i.e. you can move the compressor housing relative to the rotating assembly, and also the exhaust housing. On these smaller Mitsu turbos, there are small locating dowels that lock in their phase relative to eachother, which is why all 14b's and 16g's point the same way.
After you've gotten fairly far down the modification path, it may be convenient for you to have a turbo that points in a different direction. Most larger DSM turbos like the 20g, FP Green, and such, point downwards. For the piping in my Supra IC project, having the turbo point down and slightly back was extremely convenient, so I clocked my 16g.
Note also that this mod was easy/possible because of my external wastegate setup, which does not have to allow for mounting of the wastegate actuator for the internal wastegate. It would be possible, although difficult to re-mount the WGA after the compressor housing is clocked.
Installation Notes
This can be a little bit intimidating to do for such a trivial change. Not only do you have to know how to pull your turbo, you also have to be comfortable taking the turbo apart.
The first thing to do is to remove your turbo from the car. VFAQ.com has instructions on how to do this. Here's a short (and possibly incomplete) list of things you'll need to remove to get your turbo out of the car:
- Oxygen Sensor and Oxygen sensor housing
- 4 exhaust manifold-to-turbo bolts - 14mm
- oil feed line (17mm - remove at head)
- water feed line - (8mm clamps - remove at t-stat housing)
- water return line at turbo (22mm - bend out of the way
- oil return line (2 10mm at turbo)
- intake hose
- any boost controller lines
- lower intercooler pipe or turbo outlet elbow
If you haven't replaced the stud on your turbo with a bolt, then now would be a great time to do so. It makes getting the turbo on and off the car worlds easier.
Now that the turbo is out of the car, it is time to start diassembling it. First, remove any lines still attached to the turbo. Be sure to be gentle with the banjo bolts, and keep the crush washers in a safe place.
The first step to disassembling the turbo is to remove the turbine housing. To do this, you will loosen and remove (10mm) the large, golden band clamp that runs around the circumfrence of the turbo. Before doing that, take a sharpie and mark the position of the clamp relative to your turbo so you can reassemble it in the same place. This is not crucial, other than that the nut and bolt can interfere with the oil and water lines if it's reassembled in the wrong position.
When the clamp falls off, you will see where the turbine housing mates to the CHRA. At this point, you should be able to pull the turbine housing off of the rest of the turbo. It may take a couple of nice thunks with hammer to loosen it up. Carefully pull it off to avoid doing any damage to the turbine wheel. Note the tiny little dowel that locates the turbine housing on the center assembly. (fig. 0)
Now that the turbine is off, we have access to the large circlip that holds the compressor housing on the rotating assembly. This circlip is very strong, so you will need a good pair of circlip pliers to compress it enough to get it off the turbo. It is sufficient to simply get the clip out from under the lip on the compressor housing and leave it dangling around the bearing housing (the center).(Fig 1)
The compressor housing should now pull off quite easily. You will note that there is an o-ring going all around the back of the compressor housing that seals the housing onto the center piece of the turbo. You will also see a small notch in the center assembly that matches up to a small dowel that is located in the compressor housing. That dowel is what we are going to remove. (Figs 2-4)
Take your drill and drill down into the dowel. You don't have to go very deep - the dowel is quite small. I drilled my first hole, switched to a larger bit, and the dowel popped off in my hand. (Fig 5)
Once the dowel is removed, that is all there is to it. Run a bit of oil over the o-ring on the compressor housing, slap it back on the rotating assembly, and clock the housing down to anywhere you want it. I reassembled the turbo completely before test-fitting it on the car, since I was paranoid about dropping it and bending either of the wheels. If you do take the turbo back off the car to re-clock it, be sure to mark where you were previously, so you have an idea of how much to move it this time.
Only one special note to make on the reassembly of the turbo. Under the turbine wheel is what I assume is a backing plate of some variety. It will come loose slightly when you pull the turbine housing off, and when you rotate the turbine wheel, you will hear it scraping. Don't worry - as soon as the turbine housing is back on the turbo and tightened down with the gold band clamp, the noise will go away. Don't ask me how I know!
Impressions
Nothing much to say here, since the turbo is, still, after all only a big16g. Don't expect any kind of performance increase out of this, it's purely a convenience mod. So far I'm very happy with the result. I can get to the oil feed banjo bolt with the turbo on the car now, and can access the water return line as it goes into the main water pipe. This allows me to see if its leaking or not, and do something about it. The best part is the length of the IC piping this allows - my lower IC pipe is now extremely short to the Supra intercooler.
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