[JPuehl]

This past Saturday (1/4/2020) I started the PS2 turbo swap on my '12 135i w/N55. While I'm not going to reiterate the install steps and guides that are readily available I will share my thoughts/feedback/recommendations during the process.

As of right now, Monday morning, I have about 4 of the copper nuts holding the turbofold to the head and it will be free. Hopefully I'll have it off on Tuesday evening when I work on it again. I choose to leave the cooling and oil lines on the turbo and will try to remove them with the turbo free to give more access to the lines. If this makes it worse I'll reattach the turbo to the head and continue. I'm hoping to use bungee cord(s) to support the turbo so it doesn't hang from the lines while I'm trying to remove them. I'm trying to reuse the oil and cooling lines as the car only has 42k miles and the lines appear in good condition. Worst case is I'll replace them all if they get mangled and I have to cut them.

It took about 4 1/2 hours to remove everything needed to gain access to the turbo. I removed the front sway bar and the 2 bolts holding the steering rack to the front subframe but didn't completely disconnect it as it appears I'll have enough room by moving it.

Two notes about the engine support brace: 1. I would highly recommend removing as much from top including the turbofold heat shield and turbofold nuts as possible BEFORE attaching the engine support brace as the brace kind of gets in the way once installed. I managed to work around it but it would have been nice not to have to. 2. If you buy an engine brace, like I did, make sure you get one with long support arms, the arms that extend from the cross brace down to the fenders. The brace I bought from Harbor Freight online didn't sit high enough and I had to use a couple pieces of 2x4 to raise it high enough. It does appear if it's going to damage the fenders but it works and is not ideal.

I'm hoping to have everything back together next weekend.


Update: 2/3/2020, I just wanted to add the steps I remember taking to this post in case anyone planning on doing this swap themselves finds it helpful.

Turbo removal:
• Lift car & remove bottom cover(s), remove passenger side front wheel.
• Drain coolant & oil.
• While coolant drains, remove front top engine cover, remove intake including turbo inlet, cowl, passenger side strut tower brace, rear engine cover, heat shield above exhaust manifold, coolant fan, setup engine support.
• When coolant drained, remove coolant tank.
• From the bottom: remove sway bar, remove 2 bolts/nuts holding steering rack to sub-frame (leave tie-rods connected steering knuckles), remove coolant pump, remove FMIC including turbo outlet, remove small heat shield protecting steering racking tie rod boot, downpipe, vacuum line at WG, disconnect wires at the divertor valve, remove engine mount and stay.
• Spray oil & coolant connections with penetrating oil, leave sit over night if possible, or long enough for penetrating oil to do its thing.
• With oil drain pan under the turbo, remove the oil return line from the side of engine block, lots of oil will drain. When oil done draining remove line from bottom of turbo.
• Remove bolt holding the 2 coolant lines to the side of the turbo. I was able to access this bolt from under the car. Try to remove the 2 lines. These 2 lines can be left on when removing the turbofold so it’s not necessary to remove them but gives more room if removed.
• Remove upper coolant line from engine block.
• Remove upper oil feed line from engine block.
• Remove all cooper nuts holding on turbofold, making sure the last nut is removed while you’re under the engine to bring down the turbofold. The turbofold can be removed with the diverter valve, WG, 2 coolant lines and top oil feed line attached if done carefully.
• Note DV orientation as it can be reinstalled in 2 of 3 positions but only 1 is correct.

Turbo installation:
• With the top oil feed line and exhaust manifold gaskets installed on the turbo, push it up the same way it was removed. I found it easy to install by myself without the WG, diverter valve and coolant lines attached. I used the DV+ and found it easy to install after the turbo was in place and the upper coolant line attached to the engine block. The WG is also easy to install as was the 2 coolant lines that attach to the side of the turbo.
• Torque down the turbofold using the torque value and sequence documented by BMW.
• Install the coolant pump and coolant tank and add coolant and oil with new filter.
• Stop here, DON’T START THE ENGINE YET and “burp” the cooling system checking for leaks. I found that with the fan disconnected the coolant pump will run on its own for about 20 (or so) seconds when the car is turned on. The coolant pump will make an odd sound when running until all the air is purged from the system. I did this several times checking all connections for leaks before proceeding with the next cycle.
• Prime the engine oil by first removing the fuel injector wire connections. Crank the engine for about 20 seconds then check for leaks. I did this for 3 cycles and assumed the system was primped. I noticed that the engine would stop cranking on its own after about 20 (or so) seconds, so I didn’t need to time each cycle.
• Reconnect fuel injector wires.
• During reassembly, I stopped a couple times and verified the engine would start and check for leaks. I didn’t want to get the entire car reassembled to find out I missed something that needed a lot of stuff removed to access. I believe I did the following:
• Install FMIC including turbo outlet, connect DV wire & vacuum line to WG, engine mount & stay, downpipe, turbo inlet and temporarily connect intake. Start and let run checking for leaks.
• Finish reassembly stopping to start the engine whenever you feel the need.