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Posts: 197
Join Date: Jun 2015
Car: 2011 335i Convertible
Default N55 PWG Turbo Swap Pure Stage 2 - 03-24-2017, 02:12 PM

Originally I was planning on videotaping everything, but that didn't go very well, so this is going to be a not so great instruction list for swapping the turbo. Comments welcome. Here it goes:

I didn't find a detailed set of instructions, but what I referred to the most was the instructions labelled "N55 Turbo Swap Guide" I think that it's originally for an M135i, so the torque settings may not be correct for your car. Along with that guide, the're are some detailed instructions that came with it. I'll reference them as I go along. For the most part I follow the preliminary tasks defined in the Swap Guide.

1. Remove the Catalytic converter. For this I use "COBB_BMW_N55_********_Installation_Instructio ns". These were nicely detailed out.
**NOTE 1: I didn't do steps 14 and 15 - I left the power steering in place.
**NOTE 2: Before trying to physically remove the catalytic converter, I removed the engine mount. See below.

2. Remove the engine mount. There were 3 additional PDF instructions that came with the swap guide, they are:
A. "N55 Secure Engine in Installation Position" - I ended up getting a Harbor Freight Engine Support Bar (approx $75) and used that to support the engine. See picture. I used the tow hook as described, but one thing that I noticed was that tow hook wouldn't thread all the way in. See picture. I ended up threading it in as far as it would go and that worked fine for me. YMMV.

B. "N55 Remove Engine Support Arm" - Pretty self explanatory. The only caveat here is that the stud where the arm connects to the mount is angled towards the passenger side of the car, not straight up. So when removing the arm, you need it lift it at an angle towards the passenger side of the car. I ended up taking the arm and the mount out at the same time.
C. "N55 RWD Remove Engine Mount" - Again pretty self explanatory. With this out, it makes space to get the catalytic converter out easily.
D. Finish removing the catalytic converter following the COBB instructions. Take note of the O2 sensor wire route.

3. Remove Water Pump/Thermostat and Drain Coolant. For this I followed the DIY that Bavarian Autosport has on YouTube. It's here Water Pump Removal This is a great video.
**NOTE 1: Again, I did not do anything to the power steering rack. I left it in place.
**NOTE 2: On my car, I had a support brace that I removed one arm from. See picture. With the engine supported, I didn't mind removing it.

4. Remove the Coolant Expansion Tank. Don't forget to remove the electrical connection for the level sensor
A. Remove your OCC if you have one.

5. Remove the turbo inlet pipe.

6. This finishes the preliminary stuff. I then followed the directions in the swap guide.
A. When removing the coolant to turbo lines, the upper one I had a friend wiggle the line while I pried it out with a screwdriver...carefully. In the guide, this is picture R11 8213
B. All of the lines I was able to wiggle/pry off. I made sure to be very careful not to bend or scratch the flanges that hold them in.
C. I ended up pulling the coolant line that you removed the screws from in the first picture (R11 8202) out of the block so that I could move it out of the way to bring the turbo down out of the car. Also for re-installation. I believe you get a new O-ring in the install kit from Pure for this. Getting this back into the block was a real PITA. I ended up getting it as close as I could get and threaded one screw as far as it would go without cross threading it. Then I pried against the flange (see picture) to allow the screws to be threaded in without cross threading it. Once they were all started nicely, I walked the flange down to the block by the screwing the screws in. The whole time keeping the pry bar in place to make sure that the flange didn't move sideways.

At this point hopefully you've pulled the turbo! Congrats! Here are some pics of my removal.


7. Transfer wastegate actuator and diverter valve to new turbo.
A. (From Pure's install guide) - Using a high resolution camera, take an image of the turbocharger wastegate locknut location. Take note of the number of threads showing past the locknut on the wastegate threaded shaft. The wastetgate will need to be removed and re-installed. Maintaining the same wastegate position is critical for proper boost control.
B. There is some sort of loctite material holding the wastegate nuts in place, I only removed one nut (circled below in pic) to get the wastegate actuator off the stock turbo and I used Blue Loctite when putting it back on.
C. When pulling things off the stock turbo, I noticed stuff on the threads of the screws holding them in which I assumed was loctite, so I used Blue Loctite when reinstalling.

8. Install turbo in reverse order of the swap guide.
A. I added the DV+ bits to my diverter valve. This made it extend 3/4 inch further out. This made installing the screw that holds the oil line that is connected to the block almost impossible. I ended up replacing it with a small bolt that I had. See picture. If I had a shorter torx bit it may not have been an issue.

9. Install the Pure Inlet pipe. I found this to be a real PITA as well. The connection to the turbo is really tight and once you get it in, you can't rotate the pipe at all. You need to rotate it a little bit to line up mounting screw hole. Then once you figure out that you need to rotate it and can't, removing it is twice as hard. I spent a lot of time trying to line up the mounting screw hole because if it's not lined up, the screw will cross thread. If I ever have it off again (hopefully never) I will drill out the mounting screw hole a little bigger. This is because the alignment with the intake pipe doesn't need to be perfect as there is some room for it to move but not really because the inlet pipe has to be lined up perfect. That being said there is a screw that holds the intake pipe in place and I wasn't able to get it perfectly in either. This is the part of the whole swap that I'm probably the least happy with.

10. Install Water Pump/Thermostat and Drain Coolant. For this I followed the DIY that Bavarian Autosport has on YouTube. It's here Water Pump Install Another great video.

11. While you have room, install your catalytic converter and route the O2 sensor wires back where they belong.
A. With the V-band clamp that holds the *** to the turbo exhaust housing, I found that the only way I could get it to work was to have it behind the exhaust housing flange and then once the *** is in place, walking 1/2 of it over the flanges to put it in place. I wasn't able to put it on the *** side of the flange and walk it towards the exhaust housing.
B. I don't think I connected the exhaust to the *** at this time.

12. Re-install the engine mount.
A. The engine support bar has a nice feature where the bar "pivots" on the mounting brackets. I was able to "pivot" the bar upwards (or back towards the rear of the car) which raises the engine enough to install the mount. You can "pivot" it easily by grabbing the arm of the "hook" that you hook on to the tow hook and push it towards the rear of the car. It doesn't lock in position, so have a friend hold it in place or use a strap or bungee to hold it in the back position. This way you don't crush/lose a finger if it pivots back on it's own.

13. Connect the exhaust to the catalytic converter.

14. Re-install the under car support brace if you removed it.

15. Re-install the Coolant Expansion Tank and your OCC.

16. Re-install intake/covers etc that were removed using the COBB instructions.

17. Add new coolant and run the coolant bleed procedure as seen in the DIY that Bavarian Autosport has on YouTube.
A. I didn't use the giant yellow coolant funnel that they show in the video. I just filled it carefully. It might be worth it to run the procedure twice. When I finished running it, my level was high. I removed enough to bring it to level. Then once I ran the car at operating temperature, and let it cool down, I found that I needed to add some back in.

18. Lastly, I went back and forth on whether or not I should prime the turbo oil lines. In the end, I didn't. while searching I came across this post from Pure Turbos "Don't need to prime them. They already have a decent amount of oil in them coming off our VSR balancing machine. Install the turbos, start engine, boost your face off... " That's what I'm doing. We'll see how it goes...
Attached Images
File Type: pdf N55 Remove Engine Support Arm.pdf (234.7 KB, 233 views)
File Type: pdf N55 RWD Remove Engine Mount.pdf (205.8 KB, 291 views)
File Type: pdf N55 Secure Engine in Installation Position.pdf (452.7 KB, 235 views)
Attached Files
File Type: zip COBB_BMW_N55_******** (1.30 MB, 868 views)
File Type: zip N55 Turbo Swap (1.18 MB, 201 views)

2011 335i - JB4 ISO | MHD E85 PI BEF | Exhaust Mods | CP | 5" stepped FMIC | BMS Meth Injection | BMS Intake | Pure Stage 2 | Pure Inlet | FF wires | Fuel It Stage 2 | DV+ | N20 TMAP | Ethanol mix

Last edited by tho; 05-02-2017 at 09:22 AM..
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