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N52 Swap Discussion

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    Nando, I think, is the prototype for “people who've done a lot of 24v swap wiring it won't look that daunting.”

    I just got everything out because I don’t want to leave it until last. There’s a ton I don’t know about the N52 harness... I haven’t pulled one of these out of a car so I’ve got a lot of tracing to do to figure out what everything is that doesn’t plug directly into something on the engine. Not hard, just time.

    The Peterson CAN board is something I’m aware of... displaying oil level on the service LED’s would be awesome. It’s more in-depth than I absolutely need. I’ll read more about it to try and persuade myself I have to roll it in.

    I read through your e46/e30 cluster merge. I’ll be using a factory e30 cluster, but it certainly interested me to figure out how easy it would be to have a pigtail to connect an e46 cluster and computer controls temporarily.


      The wiring harness is not that complicated, and is somewhat modular. I went with an early 330i harness since the early harness has the relays all integrated into it. However, I used an X3 harness for the part of the harness that goes to the intake manifold sidei since it is longer than the e90 version, which allows one to install the dme in the glovebox. With oil level, I would work on installing a dipstick bung from the beginning, as its the best and most accurate solution. 2nd choice would be to just hookup to inpa or protool.


        Here’s the CAN-BUS section of the 318ti swap summary:

        Wiring/Electrical: The N52 wiring was not overly difficult. An electronic throttle pedal and associated wiring needed to be added chassis side along with the E90 EKPS (fuel pump relay) wiring. A dual function E36 coolant temperature sensor was mounted in the stock location to feed the signal to both the ECU and cluster. A CAN-BUS controller was built to intercept the check engine light signal, oil level signal, and to control the AC compressor. The N52 does not use a traditional oil dipstick so we wanted a way to monitor oil levels. The CAN-BUS signal is intercepted and converted to a signal for the cluster. The stock 6 cylinder MPG gauge was replaced with a custom dial from E30Dad to display the oil level. The 6 cylinder cluster was also reprogrammed to the stock chassis mileage at the same time by Kassel Performance. Finally the stock MSV70 ECU was flashed to override EWS and all other associated E90/Z4 modules (BimmerLabs/Kassel).
        Off of this list the oil level sounds like a luxury, but if that’s the best way of getting a check engine light I could be convinced it’s a basic need. This project didn’t involve building a pan, so a dipstick wasn’t as much of an option. We had an e46 in the family for a few years and I only remember frustration having to check the oil electronically (and being told I had to wait while the engine warmed up)

        I was expecting to be able to control the AC clutch with the e30 chassis wiring for the AC... is there something I don’t know about the n52 compressor? I think there’s just two wires and one of them is brown. What’s the story on controlling it through the bus?


          Originally posted by cwlo View Post
          The wiring harness is not that complicated, and is somewhat modular. I went with an early 330i harness since the early harness has the relays all integrated into it. However, I used an X3 harness for the part of the harness that goes to the intake manifold sidei since it is longer than the e90 version, which allows one to install the dme in the glovebox. With oil level, I would work on installing a dipstick bung from the beginning, as its the best and most accurate solution. 2nd choice would be to just hookup to inpa or protool.
          This part of your process makes way more sense now that I’ve handled the harness. I didn’t realize that each of the DME connectors was made up of removable sub-connectors that clip into the big ones. I was going to get everything plugged in under the hood before figuring out what wasn’t long enough, but if it looks like it’s only the intake side and everything else reaches into the glove box I’ll just track down that sub-harness.


            I'd like to apologize if it looks like I'm jumping around from task to task. I have a few things pending, but I'm filling in the gaps with thinking about other components... If I have downtime waiting for parts or supplies... or it's dark and raining and I don't want to be outside... I'll jump over onto drawing or thinking about something I can do from somewhere more comfortable.

            Here's where I am so far with wiring documentation. This is a pretty early look, and every single 24v swap thread I can find to look for approaches to how this works has Nando poking in casually finding huge gaps or major errors. I'm not asking anyone to proof-read this, but it's where I am at the moment. If anyone feels like they want to learn along and something looks wrong... It probably is. As I find more information this link will get updated, and eventually when I know the car's running I expect I'll post this in a more permanent format. There's a ton more work to do here... not the least of which is this is done from the 330i Bentley manual... so any data connections likely need to be updated for the Z4 DME flash (I expect that's why I stalled out on the fuel pump connections).

            Colors are read from actual connectors I have sitting on my desk, so there's likely some dark grey/black/dark purple or white/yellow mistakes. I didn't bother looking to see if BMW documentation has these colors because this makes my brain hurt already... I don't want to have to translate from german color abbreviations.


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              I'd reference the TIS in case the Bentley has errors (like they often do). It has a table of the DME pinouts and every function. Actually, I have them saved somewhere as PDFs for easy use. You can cross reference the Z4 pinout with the 330i, but they are essentially the same as far as the swap goes.

              as far as colors, most of them are pretty easy, but it helps if you've had classes in German. But I think there's a translation chart of colors from German to English somewhere in the TIS as well, if not in the old ETMs.

              I like your diagrams of the ports on the connector. Sometimes that's hard to follow except by rogue memory or counting pins..
              Build thread



                The colors aren’t really critical and are going to vary from model to model... I mostly just needed to go through this exercise to force myself to read and name all the functions and know where they’re routed. I’m happy to go through the translation to find a wire when I’m looking for one from the TIS, but this is more so I can orient myself when I’m looking at a bundle halfway down the loom or at the back side of the fully populated and connected plug (wait is that 1-13 or 14-26???)

                My expectation when I go back and compare this to the Z4 TIS is that the data labeling will make more sense. Maybe it’ll help me see the matrix ;)

                Im going to revisit the spreadsheet soon after I read up on m54/s54 wiring and apply that knowledge. I’ll add some notes to the top and will highlight areas that I’m unsure of so if people want to break out and research something they don’t have to dig through the whole thing to try and find an error.

                I certainly found errors and typos in the Bentley table. It was useful for a general reference, but there were critical mistakes, and there’s some others that I suspect are wrong as well. If you start stripping connections out of the loom based on the Bentley you’re gonna have a bad time.

                Also, don’t believe anyone who tells you I stopped working on the motor arms. Click image for larger version

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                  Well it looks like there's at least a 5th way to make a motor mount arm for this swap.


                    Based on what I'm seeing in your picture of the motor mount. It looks like the rubber mount hole still lines up with the two holes above on the block, which is the factory Z4 configuration. Is this where you plan to place the motor? Click image for larger version  Name:	20200625_180134 (2).jpg Views:	0 Size:	82.9 KB ID:	9940593


                      Boy that's a good question. I'm going to be pretty frustrated if the only difference that the Z4 arms need is the Z4 engine mounts. There's very possibly still differences in the angle and spacing between the mounts that could mean the z4 arms wouldn't work, but here's a shot pretty much square-on. My engine mount bolt is just behind the center bolts. The other shot is where the shifter lands when the engine is in this position.

                      Post #29 here has CWLO's engine position. It's possible he shifted it back just because there was a TON of room behind the engine. It certainly looks like there's a ton of room behind my engine, but with the 3-stage manifold the heater core stubs you see start to get pretty close to the plastic intake (his intake is shorter because he's using the N54 to retain his brake booster).


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                      Although I'm using the Z4 motor mounts rotated 90 degrees, so it would have to be a huge coincidence:

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                      On the Z4 subframe the pin and bolt are longitudinal to the chassis.
                      Attached Files


                        The way that I've understood it so far, is that CWLO took the Z4 arms and sawed them in two. He then shifted the motor side back (towards the firewall) 1" and then rewelded the arms. He didn't change the height.

                        I happen to have those same arms because they were attached to the motor I bought that came out of an '07 Z4.

                        This particular aspect is what I was trying to get clarification on. Seems it's still unclear, at least to me.

                        I based my mount arm designs on the " 1 inch shifted back " assertion. Which basically amounted to moving the rubber mount hole toward the radiator 1". I'm very familiar with the relationship between the holes after modeling them a few times. That's what stood out to me and why I brought it up.

                        The other thing CWLO said was that he had to shorten the shift arm and linkage.


                          Well, those two statements seem to be consistent at least ;)

                          There’s no n52 z4 engine arms on eBay. Your photo above might be the The first time I’d really see lined up like that.

                          I remember doing some mumbled reasoning that since m54 swaps use e36 arms (and not z4 engine arms) with e28 m5 motor mounts that they couldn’t be the correct shape, and that’s why CWLO had to cut them.

                          I think the only thing to do is for me to have a set available to try when I set the engine package back in and decide whether I use the z4 arms or my hacked together plate arms.

                          That sucks a *little* because I don’t want to have to torque the arm bolts on in-place...


                            Sorry I didn't make that clear, at least from my point of view, earlier.

                            If you haven't welded the mount arm, then it's still adjustable.

                            The way I'm looking at the passenger side mount is that I'll be able to drill and spot face a new rubber mount hole 1" from the existing hole. It seems there is solid material there and the hole will move to a 'stronger' spot overall.

                            But I won't know for sure until I try to machine it. It's seems like the 'easy one', so I concentrated on the driver side because moving that hole forward 1" is not as simple.

                            You can see on the mount arms pictured above where I drew the new locations with sharpie.

                            But it's still just theory at this point.


                              Here's the driver side mount:

                              The passenger side mount is on EBAY: 2006 Bmw Z4 Convertible E85 3.0 Front Right Engine Mount Support Bracket


                                I have a bunch of mounts. I'm pretty sure I have that driver's side one.
                                Build thread