heinzboehmer's 2002 Topaz 6MT Coupe

[D-O]

More like 25 HP - plus the weight savings.

[0-60motorsports]

Yep! 61349316116

Cheers

[heinzboehmer]

Thats cool. Got a pn for the plug?

Yep! 61349316116

[0-60motorsports]

Thats cool. Got a pn for the plug?

[heinzboehmer]

Okay so INPA does not show EGT. However, I did learn that DIS can grab a ton of information from the DME under DME -> Expert Mode -> Diagnosis Requests.

Here's EGT (amongst other sensors):



And a sample of other interesting things like oil level and VANOS timing:




Now just need to sniff D Bus while I open up all the different screens to reverse engineer all this data. Honestly sounds like a lot of tedious work, but having all that data in a log does sound very appealing...


Also, I can't believe I forgot to show off my most important mod to date! Easy 20 hp from this thing:



In all seriousness, the open 12V socket was annoying me so I bought one of the modern BMW 12V socket plugs. Don't smoke, so no need for the cigarette lighter one and I like how this one is less busy.

[Bry5on]

Brilliant idea to record the traffic during an INPA session

[heinzboehmer]

Stuck home with a cold this weekend, so I knocked out some boring maintenance that I had been putting off for a couple months.



Swapped fuel filter, filter to fuel rail line, EGT, PCV line that goes to the airbox and a bunch of underside trim clips/screws that were starting to get old and worn. Always fun to do your best to evacuate the system of fuel beforehand, only to still have it spill everywhere.

Everything else was uneventful. I haven't seen the intermittent EGT code I was getting pop back up and EGT readings on Gauge.S are different now. I say "different" and not "correct" because it's clear the scaling is still way off.

Originally, I was planning on using this new sensor to calibrate the Gauge.S reading. DME has this table for the sensor:



And a third degree polynomial fits it perfectly:



So, it should just be a matter of exposing the sensor to a few known temps and measuring its output to correlate it with the graph.

I was about to head to the kitchen for some ice water when I realized that the DME is likely not sending out the raw sensor values over D bus. All other temp sensors are scaled linearly in the output data, so it would be very unlikely that this one is different. I'll check to see if INPA or DIS show EGT. If they do, it should be super easy to figure this out using a technique like this one: https://github.com/tomicooler/bmwe46...il-temperature

I did also set up the cheap logic analyzer I got and started trying to figure out why the V5 Gauge.S doesn't work with the DME, but the V4 does. Here's version 1 and 2 of my D bus probing setup:




I haven't really gotten anywhere yet. The V5 board on older firmware was sending out the correct DS2 commands, but would then hold D bus low and not allow the DME to respond. Updated the firmware and swapped the janky trimpot I had used as a D bus pullup for a properly sized 10K ohm resistor, then tested again.

Janky:



Not janky:



Now Gauge.S sends out the correct command and the DME responds with a valid response, but for some reason the device still does not display anything. It communicates just fine with the MK60, so I'm fairly convinced this is a FW issue. Unfortunately, Gauge.S FW is closed source, so I can't really debug this...

Anyway, I'll keep messing with this and update with any resolutions.

[heinzboehmer]

Small addendum to the phone holder project. Drove the car a bunch last week and found two issues with the bumpers that hold the phone in place:

• Top bumper is designed to be a press fit into the top tab. The top tab has a rib in it for rigidity, but because of packaging reasons, it had to face down. This means when the tab + bumper are pressing against the phone, the bumper is also being forced forward. After enough vibration/time/etc. the bumper will fall off. Was fun trying to catch my phone lol. Some visual references of the design:

One good solution would be to add a ledge to the end of the tab that will hook into the bumper once installed. However, this would leave overhangs inside the bumper and I really didn't feel like spending a bunch of time trying to print an overhang without support using that super soft stuff. So, a dab of 3M emblem and trim adhesive was the solution I picked.

• Turns out the super soft filament was too soft for the bottom bumper. Again, after enough vibration cycles, the phone would scoot forward just enough and bend the bumper out of the way. Was also fun to try and catch it when this happened. To fix, I extended the bumper forward by 2mm (to cradle the phone a bit better) and printed it out of the harder TPU. This bottom piece is really just acting as a rest for the phone, so the hardness of the material doesn't really make much of a difference with how well it's held in place.

Besides that, holder has been great! Pretty happy with how it turned out.

[heinzboehmer]

Annual wheel bolt replacement came a bit early cause I noticed some slight surface rust on some of the rear bolts. It's very orange (i.e. newer), so likely just from heat cycling at the track and getting washed.



The ease with which I can replace these is the number one reason why I don't have a stud conversion kit installed

[heinzboehmer]

If no one else tells you this let me, this development of the vent phone mount has been awesome! Also if you ever feel bothered to print another I would love to buy one

Thanks!

Here's the CAD if anyone wants to print it out: https://cad.onshape.com/documents/aa...abcccfec208abd

Anything suffixed with "Bumper" is made to be printed out of a flexible material (regular 95Aish TPU works, but the super soft 60A stuff works better) and everything else is made to be printed out of ABS or similar.

[nextlvel]

If no one else tells you this let me, this development of the vent phone mount has been awesome! Also if you ever feel bothered to print another I would love to buy one

[heinzboehmer]

Hell yeah, this super soft filament is awesome. Bit of a pain to print, but not too bad.

Shocking, but it turns out all the things I read on the internet were correct. I ended up needing to cut a small hole in the side of the extruder case so that the tension screw could be backed out. Messed around for a bit and found that backing it out 6 full revolutions from all the way in worked well. I also had to bypass the regular filament feed tube and kinda just drape the filament in the chamber. Feeding it through the feed tube resulted in too much friction, which would make the extruder gears slip. If I wanted to print much bigger parts, I probably would have to come up with a way to suspend the spool above the chamber and have it roll with very little resistance.



Prints came out well and now the mount is much grippier. Filament is so soft that I ended up having to print all three bumpers using 100% infill. Still only required about 6g of material, so happy with that.

Anyway, back to regular BMW stuff. I noticed that the horn on the new steering wheel didn't feel like it should. Kinda felt like there was something in the way of the contacts, as you had to press decently hard to get it to honk and the regular metal on metal click was not present.

Took the wheel apart and found that all three horn contacts had some wear on them:



Cleaned up with some scotchbrite:



Nice to have a clean contact surface, but this did not fix the issue. Turns out that the contacts had worn down enough that the rubber bumpers next to them were making contact first. If I pressed hard enough, I could slightly deform the bumpers and get the contacts to touch, but the feel was terrible.

Fixed this by slightly trimming the bumpers:




Clicky horn is back!

[heinzboehmer]

Okay last version finished.

Integrated an intake manifold into the vent mounting mechanism, which then ducts through the mount arm and comes out behind where the phone sits. I also added a cover in case I ever want to block the flow.






All was good until I went to test it out on the car and found that absolutely no air was making its way into the duct. Turns out I should have done my homework before going through the trouble of adding this feature. Here's a topside view of the vent:



You can see that the two chambers are completely separated from one another. Well, it turns out that the one the mount attaches to (the one facing the door) only ever has air flowing through it when the defroster is turned on, which isn't particularly useful for cooling down my phone.

I was in too deep at this point, so I busted out my favorite of the two CADs and got to work modifying the vent. Designed and printed a shutter that allows air from the main chamber to flow into the smaller one and eventually into the mount:




Added some detent and limiting features to the sliding part of the vent so that it can be set to allow airflow between the two chambers or not.

Open:



Closed:



To install, I slid it into the vent (hence the locating arm on the opposite side of the shutter) and marked its position:



Then I used that reference and the holes in the shutter to mark out the area that needed to be cut:




Last step was to glue it on:



And this is right about where my motivation to work on this project died. I was planning to design a feature that extended out through the vent so that you can just slide the shutter back and forth with your fingers, but I just couldn't be bothered. Instead, I took the lazy approach and printed out a "special tool" to stick through the vent and actuate the shutter with. Metal pick works just as well, but I wanted something made out of plastic so that I wouldn't accidentally scratch the interior up:



We have now reached the end of this project. Well, sorta. Just got the super soft filament today, so will be reprinting the bumpers out of that. But no more iterating on the design or I'm gonna drive myself nuts.

[heinzboehmer]

Wait, what am I doing. The current vents are a terrible design.

The air should be coming in through the mount. Should be able to channel a lot more volume that way. Guess I'm used to thinking in traditional manufacturing ways, where features within a part are a pain to make. 3D printing is the perfect tool for that kind of thing, however.

Okay well, new version coming soon. I should really stop iterating on this stupid thing...

[heinzboehmer]

Been driving around with the latest revision of the phone mount for a couple days. Think this is the last iteration of it for a while. Works great and I don't really see any more glaring issues. Here's a quick summary of the changes I've made since the last post about it:

• Phone mount surface tilted 10 deg down and rotated 1.5 deg CW
• Dash support leg angled out towards dash to make them more orthogonal
• Added draft to the surface facing the door to fix slight interference (~1mm)
• Added zip tie holes along dash support and main arm to hold future charging cable
• Reworked top tab geometry to integrate displacement limiting features
• Added air vents through the body of the mount

Have yet to see if the vents do anything. Figured that I should add them since the AC vent is right there and it might be nice to be able to cool my phone on hot days, especially if it's in direct sun. The intake of the vents is through the back of the mount and they come out the front. Did it this way to keep as much stiffness as possible (at least I think this way is stiffer?). Cross sectional area of the vents is tiny, but I think a smaller amount of directed air is better than a splat from the vent. Plus, even with the vent pointed all the way up, it really only manages to hit the bottom ledge of the mount.

Couple pictures of this latest version:




The only thing I am going to modify is the material for the top and bottom "bumpers" (the features that actually hold the phone). They're currently printed out of 95A TPU (Polymaker PolyFlex TPU95-HF), which works fine, but is a bit too slippery. I can see my phone shifting around a bit after some driving. Planning on printing those out of the softest filament I could find: Recreus Filaflex 60A. Should up the coefficient of friction significantly and help grip the phone a bit better.

Seems like it'll be a bit of a challenge to print, but we'll see how that goes. Gonna leave some links I found about printing with super soft filaments here, for future reference:

https://forum.bambulab.com/t/setting-the-extruder-pressure-for-soft-tpu/40022

https://forum.bambulab.com/t/adjust-tension-on-extruder-wheels-for-printing-very-soft-tpu/4897