heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

I can help you make one sided molds for aluminum or steel ‘stamping’ if that’s where we end up. No problem

Awesome. PET-CF filament is finally back in stock, so I should be able to test it soon

[bigjae46]

Really? The reason I mentioned CF is because some random website told me epoxy resin was good up to around 300 C. You have more experience with this than me though.

I'm trying to avoid the composite thing because I think it'll be very hard to get right. Hopefully the PET-CF survives.

The carbon will survive but the epoxy is the limitation. There are other processes that can raise the Tg of the epoxy but it would be extremely expensive.

For example… carbon ceramic rotors have no epoxy, made with heat and pressure. Lots of it. There might be an aerospace epoxy but it would also require a lot of heat and pressure.

[heinzboehmer]

Some small tweaks to the mounting design of the duct. Extended the rear tab down and added a collar for rigidity. I really don't want this thing slipping off the caliper at speed. I also clearanced the front a bit more to make it easier to install:



Printed a slice of it to verify rear fitment. Very pleased with how well the lower surface fits up against the caliper. I just straight up intersected my model with the 3D scan (cause lazy) and it came out great!



Then PET-CF finally showed up, so I printed the first prototype suitable for testing:



This filament is so cool. Feels very futuristic to click a button and have a composite part come out a few hours later.

Very pleased with how it turned out. Next up is temperature torture testing!

While I was in the area I also swapped the fender liner:



This is one of those things that I just kept forgetting to replace. Finally remembered to order one and got it installed. Old one had definitely seen better days...

[heinzboehmer]

Next up some projects I stole from Bryson.

Harness made to grab CAN from the steering angle sensor:





This will be used for the wideband O2, Gauge.S and to bring CAN to the ODB II port.

Installed:




Still need to go the junkyard and grab some connectors with the rest of the Gauge.S harness, so the installation is kinda temporary. Will likely change some of the routing once I install everything.

Wideband O2 installed and harness tucked away to keep it out of sight and away from the headers:




Also printed out the Bryson Gauge.S enclosure and test fitted:



This thing is super cool. Can't wait to have it hardwired and working all the time.

I did find a tiny USB C fast charging board and altered the enclosure design a bit to fit that in:




Supposedly this thing can do 45W fast charging (per port, so total 90W), but I don't trust that there's a boost converter on there for the 20V 45W fast charging. I bet the most it can do is 12V 36W, which I'm totally okay with. Will still be way faster than just hooking up 5V to the USB C ports. This thing is overkill anyway since the wireless charger keeps my phone charged, but I wanted to have fast charging in case I ever get stranded on a super long roadtrip and the only way out is to trickle charge my laptop with the car

In parallel, I modified and installed the Bryson brake scoops. I had previously cut holes in my dust shields for brake cooling hose flanges, so I conformed the scoops to the hole shape in my dust shields.

Flanges removed and ABS scoops test fitted:




Some small tweaks were needed up top, but they fit great. With the fitment confirmed, I also printed these out of PET-CF. Kept the lower scoops made out of ABS cause that PET-CF material has been very hard to get and I only managed to buy 500g of it. Lower scoops should see much lower temps anyway, so I'm not too worried.




Next thing I need to do is visit a junkyard to grab parts for both the M3 and the E82. With those, I'll be able to finish up the Gauge.S harness and then start my DIY engine tuning journey!

[heinzboehmer]

Oh! Pictures from the last track day were released recently. Here's some slow racecars trying to catch up to the PT3RS:



My favorite picture of the day by far.

[heinzboehmer]

Finally had enough of the rattle coming from the unfiltered section of my airbox, so I designed some parts to fix it. The rattle was coming from two spots:

1. The holes for the pins are way too big and allow the unfiltered section to rattle around.
2. The cap for the idle air hole that Karbonius sent me doesn't fit perfectly, so that too rattles around.

To fix, I printed an idle air hole cap that somewhat mimics the design of the flange on the CSL part that's supposed to attach there and some "bushings" for the pegs. Decided to print both out of flexible TPU instead of ABS because its flexibility will help dampen out any vibrations and should keep everything rattle free.

Cap:




"Bushings":



So far so good!

I'm slightly concerned about the longevity of the bushings, as I had to print them in the same orientation that they're in in the picture. This means that the layers are in the same plane as the carbon on the unfiltered section, which could conceivably cause the adhesion between the layers to fail (essentially cutting through the part) given enough vibration cycles. I did try to print them on their side so that the layer lines would be orthogonal to the carbon, but it was super hard to get them dimensionally accurate that way.

I did try to slice through one of my test prints with a razor blade and it was surprisingly difficult, so maybe they'll be okay. If not, it only took like 8 min to print all three, so I could just replace them every couple years or whatever. Worth it so that I don't have to listen to the rattle every time I pull away from a stop.

[NW55]

Just came across this amazing journey. Thanks for sharing. The topaz is stunning.

[heinzboehmer]

Just came across this amazing journey. Thanks for sharing. The topaz is stunning.

Thank you! Appreciate the kind words.

[heinzboehmer]

Finished up the Gauge.S install. Started by making a harness that connects to my previously installed eject box power source and powers Gauge.S and the CAN wideband controller. It also has CAN coming from the steering angle sensor and K bus coming from the 18 pin connector on the IHKA (note: do not try replicating the K bus part, more on this later).



From left to right: IHKA K bus, CAN, eject box power, CAN wideband power and Gauge.S connector.

Installed:






Took it on a test drive and quickly found that the K bus was freaking out. Passenger mirror wouldn't dip in reverse, turn signal blink frequency varied a lot (which was surprisingly disorienting), radio settings would randomly change, etc.

So, I reached out to the person with the most K bus knowledge (t3ddftw) that I know of for some pointers. Ted immediately knew I had wired something wrong and was a huge help, as always. Turns out that "K" on Gauge.S (shown below) is not referring to the K bus, but rather to the OBD II K line. Thanks again for everything Ted!



So I basically caused the K bus to get flooded with a bunch of DME diag messages, which is why different modules were freaking out. In hindsight, I should have realized that the K bus was not the correct bus to hook up to, but I was working on multiple projects at the same time (what a surprise) and didn't think anything of it.

Anyway, what this thing should have been connected to is the D bus. On the E46, it's split up into two sections, labelled 1 and 2 on TIS. 2 is more of a connection than a bus really, goes from pin 7 on the ODB II port to the DME (and from DME to transmission ECU on autos). 1 is an actual bus and connects to a bunch of modules, as well as pin 8 on the OBD II port (this is why pins 7 and 8 need to be connected on cables when using INPA etc.). One of the modules D bus 1 goes to is the steering angle sensor, so I pulled out the harnesses I made and modified it slightly.

D bus 1 tap added to the harness I made earlier:




Then removed the whole K bus section from the main Gauge.S harness and added a wire for D bus 1.



The ODB II port cover has some contacts that pull up both pins 7 and 8 to 12V when it is closed. Removed the pullup resistor and now this cover serves as a bridge between D bus 1 and D bus 2:




Tested and everything worked this time around!

Last thing to finish up before permanently installing was the USB ports. Wired the USB C charging board up to the small adapter harness I made:




I don't love this harness for a couple reasons. First, I really dislike using those spade connectors to tap into the cigarette lighter socket, but I couldn't find a better spot to tap into that could handle 7.5A (since this thing is supposed to be able to charge two devices at 45W each). Second, I didn't have connectors that could handle the wire gauge, so that means the whole center console has to come apart to get the Gauge.S out. In the future, I might add a new, dedicated fuse for this charger and then add a connector underneath so that it's easier to remove. But for now, it's good.

Put everything together and it's working well:



Then tested the USB C charging with my laptop:



As expected, it's not doing 45W, but I'm still pleased with 36W.

I messed around with the config files a little bit, mostly just to get the AEM wideband working, but still need to dedicate some time to that. All in all pretty happy with how this turned out!

[bavarian3]

Still need to catch up on a bunch of things, but thought I'd document my most recent project, as the details are still fresh in my mind.

In preparation for the SSV1 install, I decided to build my own DIY euro O2 harness. I mostly see people cutting open the conduit that runs from the DME area to the engine and fishing out the O2 and EGT sensor wires. I couldn't come up with a satisfactory way to do seal the conduit back up (electrical tape was not an option, I don't like the stuff), so instead I decided to depin the wires in the DME are and reroute them through where I wanted them.

Initially, I wanted to depin the wires from the connector side, but I wasn't sure I'd be able to do so without damaging the pins. I started with the wires that go to the X60002 connector, as those are the easiest ones to depin. Tied some twine (don't judge, that's all I had) to the pin in case it got stuck along the way and needed to be pulled back.



I did have to babysit it as the knots in the twine were getting caught up in places, but it was not big deal:



Success!




Now that I knew there were no pieces of tape or anything within the conduit that would make the wires snag, I removed the rest of them. I decided to just remove the whole harness and do it off of the car, so that I had better access to everything. Here's the post-cat O2 and EGT parts of the harness free of the main one:



The biggest modification I had to make was to the crimped ground and power "bundles" in the DME area. This is what I'm talking about:



You can see I cut off one of the wires from the bundle so that I could fish it through the conduit. In the end, I just cut off the whole crimped part and soldered everything back together, like so:



I then added some adhesive-lined heat shrink over the solder joint to make it as water proof as possible:



And also put the green cap back on to make it look factory:



Here's the finished product:



I fed the post-cat O2 and EGT sensor wires (with some extra conduit covering the bare wires) through the same place that the transmission sensors wires go through, so that it mimics the euro harness. Forgot to take a final pic before I put it back on the car, but I also added some adhesive-lined heat shrink to the point where the post-cat O2, EGT and transmission sensor wires join the main harness (bottom right in the previous pic).

Pretty happy with how it turned out. Basically a factory euro harness now and it only cost me a few hours of my time, instead of $600 or so.


Edit: These are the TIS sections I referenced for the post-cat O2 and EGT wiring.

BMW E46 M3 Coupe / Electrical Components / Connectors / Components / A: Control Units, Modules / A6000 Control unit, Digital Motor Elecronics /

BMW E46 M3 Coupe / Wiring Diagrams and Functional Description / Power train / Engine control / Digital Motor Electronics / Sensor / Oxygen sensors /

BMW E46 M3 Coupe / Wiring Diagrams and Functional Description / Power train / Engine control / Digital Motor Electronics / Sensor / Catalytic converter temperature sensor /

Phenomenal work, and thanks for the walkthough. It seems simple enough. I think this route makes much more sense since it avoids hacking up the harness. Any specifics or tools needed for the de-pinning process, or simple enough?

[heinzboehmer]

Phenomenal work, and thanks for the walkthough. It seems simple enough. I think this route makes much more sense since it avoids hacking up the harness. Any specifics or tools needed for the de-pinning process, or simple enough?

Nothing too specific! A small flathead screwdriver should get you through everything. Just make sure to label all the wires (or do them one at a time) so they don't get mixed up.

[WestBankM4]

Great write up Heinz! This thread is motivational, now I really need to get off my butt and start working on the ///M again.

[heinzboehmer]

Great write up Heinz! This thread is motivational, now I really need to get off my butt and start working on the ///M again.

Thanks man! We should get that airbox installed on your car

[heinzboehmer]

Alright, another iteration to the Gauge.S install. First, jumped on DigiKey and ordered a bunch of TE connectors and housings. Then I added a FET-based relay board (so no annoying clicks) to the USB C charger so that it only comes on when the key is in the ignition.

Connectors added and harness modified:






This new connector makes removing/installing Gauge.S sooo much simpler, it's pretty great now.

I also found this nice TE housing for the right angle cigarette lighter ground wire. Really no need to have this as it's a ground, but it makes my brain happy:



I then reinstalled the SAP cause I was tired of the ridiculous stink on cold starts:



It did make it better, but it definitely doesn't smell like stock. I guess that's just down to the composition of the cats. Seems like they need a good bit of heat in them before they start doing anything. I'll take any improvement though, so still worth having this thing back on.

And lastly, all that key on engine off work made it clear that my battery was truly dying. So I finally jumped on the lithium train with an H5 40Ah Antigravity LiFePO4 battery:



Old battery (H5 CSL/mini sized lead acid) weighed in at 32.6 lbs. Lithium one is 13.8 lbs. Happy with the 18.8 lbs saved!

Also very entertaining to hear the starter turn the engine over so quickly now. I'm also fairly certain the locks actuate faster with the lithium battery, but I might be making things up with that one.

[heinzboehmer]

On another note, I've been running Bry5on's mullet tune for some weeks now and have nothing but positive things to say about it. I'd say it's about as big of a jump as it was when I did the lambda integrator part throttle fuel tuning. No more weird hesitation at lower RPMs (there was a very noticeable one at ~2.7k that seems to be gone now), downshifts are super consistent now and there's torque!

I find myself downshifting a LOT less on the street now. Pretty great to have the car respond to throttle pedal inputs at lower RPMs. Feels very close to how I remember the stock tune (with stock hardware) feeling like. I'm super happy with the drivability and, as a bonus, my wideband is showing pretty much spot on AFRs everywhere.