Liam821's e46 324i k24/dct/turbo build

[liam821]

I have had almost no time this week, so many things going on. But I still snuck out into the garage for a few hours here and there.

Clean black carpet going in. Amazing how much better it looks - even without the dash


Dash support bar back in.


Replacing the center console buttons with one from an M3. This gets me the TPMS and Sport button.


For those wondering about wiring, there is a great DIY on zhpmafia about wiring in the TPMS. It's a single wire (pin 2 of the control buttons) into the MK60 ABS pump and then some coding. Easy peasy. The sport button has two pins (17 and 18), one is the switch that goes into the DME in an input, and the other is just a low-side ground that lights up the sport LED. Since the stock BMW DME is getting the boot, the sport button is going to be wired into a Canchecked MCE18 input/output canbus expansion module and then will talk over canbus to the Maxxecu - since my Maxxecu race inputs and outputs are at a premium. I'll have the sport button configured to turn the car to max effort (full boost, exhaust cutout open, transmission in drivemode 5 etc) with a single click - "M" mode? haha

A few other goodies I wired in as well were the e39 windshield washer button, which will flip through a preset list of boost/power settings. And the most exciting button, the MDM ZCP steering wheel button, is now launch control (if stopped) and the rolling anti-lag (if moving).

[liam821]

Small update. I've had no time the last few weeks, too much stuff going on. But I did finish a small project.

I needed to get the e46 M3 SMG paddle shifters working with the DCT. The SMG cars had a specific clockspring aka "Switch steering column slip ring" which passes all the steering wheel buttons but adds two more pins for the up and down paddles. Some of the newer BMWs use a single wire but add two difference resistance when pulling up or down so it's a bit more involved. Thankfully, the e46 M3 SMG is simple, each paddle has its own pin that grounds to the steering wheel (chassis) ground. Keep in mind that manual cars (non-m/M3 manuals are the same) clocksprings are different than SMG cars, which adds two more pins for each paddle. So you need to source a SMG clockspring. I thankfully had a spare.

Now the E92M3 DCT TCU paddles work the same way as the e46, connecting ground triggers an up or down shift. However, it requires the up and down paddle to use it's OWN TCU ground and not chassis ground. So I have two options: I can route the TCU ground through the steering wheel clockspring, or I can use some sort of relay that will connect it's own ground on request.

I decided not to mess with all the steering wheel wires and use a relay instead. Now I don't want to hear a "click click" of a relay every time I pull a paddle so instead let's use a mosfet instead. A mosfet, or Metal-Oxide-Semiconductor Field-Effect Transistor, is a type of semiconductor device used to amplify or switch electronic signals. It's essentially a voltage-controlled switch, where the voltage applied to the "gate" terminal controls the current flow between the "source" and "drain" terminals. It's basically just a fancy relay. And since it uses transistors, it offers fast switching speed and a longer life then your traditional relay.

So I went on a search for a mosfet to fit my needs and found that the Panasonic AQY212S will fit the bill. They cost $2/each from digikey.com. You can get them in both DIP (pin mount) AQY212EH or SMD (surface mount) AQY212S style chips. I chose the SMD style chip and use a SMD proto board to mount everything. The wiring is very simple.

[12V Switched] ----[1kΩ Resistor]-----> Pin 1 (Anode)
[Paddle Switch] ---------------------------> Pin 2 (Cathode) (to GND_CHASSIS when pressed)

Shift up/down to TCU --------------------> Pin 3 (Drain)
TCU_GND ----------------------------------> Pin 4 (Source)

The resistor on pin 1 limits the current going into the mosfet.

This is by far some of my best micro soldering I've ever done. This is not my profession, I'm a software engineer, not an electrical engineer.


Close up using my desk microscope, came in clutch doing the soldering.


Here are all the wires soldered on and wired into the car harness. I was able to test to verify that it works perfectly. I wired them into ACC 12v power, plugged in the battery, and pulled a paddle to get that satisfying beep of my multimeter! wooo


I also finished all the wiring I need. Here are the things I've added:

Center console TPMS & sport buttons. TPMS goes into the MK60 ABS module, sport button is routed into the Maxxecu.
E39 wiper stalk button is routed into the Maxxecu.
Paddle shifts which we just talked about
E92M3 dct shifter 12v ACC power is using the old automatic wiring harness, but with a Deutsch connector
DCT gear display wired into gauge cluster power/canbus (also using a Deutsch connector)

And I think that's about it. I didn't have to add/change much of the wiring in the cabin. Everything was Tesa taped together and routed just like factory. Everything looks factory, except for the Deutsch connectors. I thought about sourcing OEM-style TE/AMP connectors but it's a bit of a pain in the ass and nobody is going to see it.

The last update I have is BMW of NorthWest in Tacoma, WA FINALLY got the slicktop roof panel I ordered. Took 6 weeks to get here from Germany. It was only supposed to take two weeks, I'm assuming all the tariffs and shipping delays caused this delay as well. But I was able to grab it! One of the last left new in the world.

It came in a huge box which said "glass" with lots of padding inside, uhh is that going to fit in my X5?


Yep, no problem


Next steps is getting the dash in and starting the Maxxecu wiring engine bay side. I also need to pull the stock M54 and get the K in the engine bay. Future Liam.