heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Love it!

Lol, that seems to be the story for all the doing projects I table on this car

You're making a mold? Have to be careful with any vertical surfaces. That may cause release issues. Need a slight draft angle...maybe 1-2 degrees?

Have to factor in exotherm with the mold. Could see up to 200-300 degrees depending on the exact epoxy you use.

Just gonna print the part, not a mold.

Rough math says that making it out of carbon + cork core will weigh around the same as the printed part, so not even gonna bother trying. The modern printable materials can take heat really well, so I see no downside to printing.

[bigjae46]

Also, this took absolutely forever:

I started with this piece cause it looked simpler than the cabin air filter housing, but, man, was I wrong. Essentially no surface on it is flat, except for the one that butts up against the firewall. Took me a really long time to figure out how to approach all of the curves.

Yes, I realize that a lot of the geometry is there for mold release, but I want to make something that fits all E46s, so I decided to spend the extra time and recreate it as closely as possible. More time spent in CAD land saves me from redesigning the piece down the road if it turns out to not fit on some other chassis configuration.

I also decided to not model the front clip retainer into the piece. I like the idea of using the stock injection molded piece for serviceability. BMW does not sell these separately, so I'm gonna have to go junkyard diving for some. Fortunately, they're just plastic welded in, so they're easy to pop out with a razor blade. This part could also conceivably be recreated, but printing it in a favorable orientation might be tricky.

Also, did some preliminary slicing of the model and the printed version should weigh in at 300-400 g, depending on my choice of material and infill. For comparison, the stock piece weighs in at 1618 g. I do need to split it up into three pieces to fit in my printer, so I'll add some features to bond all of them together nicely. For now, I just added some slicer-generated dowel connectors:

With the stock geometry recreated, I can work on modifying it to accommodate both the braces and the tilted filter. Got some ideas flying around in my mind already for how to approach that. More to come.

Sidenote, since I essentially made a 1:1 replica of the piece, anyone can print it out without modification and save ~1.2 kg. Who's up to be the test fit guinea pig? Hit me up and I'll send you the stl (I'll distribute widely once fitment is validated).

You're making a mold? Have to be careful with any vertical surfaces. That may cause release issues. Need a slight draft angle...maybe 1-2 degrees?

Have to factor in exotherm with the mold. Could see up to 200-300 degrees depending on the exact epoxy you use.

[George Hill]

I started with this piece cause it looked simpler than the cabin air filter housing, but, man, was I wrong.

Love it!

[0-60motorsports]

Thats amazing! I would so buy this from you once its all done.

[heinzboehmer]

Also, this took absolutely forever:




I started with this piece cause it looked simpler than the cabin air filter housing, but, man, was I wrong. Essentially no surface on it is flat, except for the one that butts up against the firewall. Took me a really long time to figure out how to approach all of the curves.

Yes, I realize that a lot of the geometry is there for mold release, but I want to make something that fits all E46s, so I decided to spend the extra time and recreate it as closely as possible. More time spent in CAD land saves me from redesigning the piece down the road if it turns out to not fit on some other chassis configuration.

I also decided to not model the front clip retainer into the piece. I like the idea of using the stock injection molded piece for serviceability. BMW does not sell these separately, so I'm gonna have to go junkyard diving for some. Fortunately, they're just plastic welded in, so they're easy to pop out with a razor blade. This part could also conceivably be recreated, but printing it in a favorable orientation might be tricky.




Also, did some preliminary slicing of the model and the printed version should weigh in at 300-400 g, depending on my choice of material and infill. For comparison, the stock piece weighs in at 1618 g. I do need to split it up into three pieces to fit in my printer, so I'll add some features to bond all of them together nicely. For now, I just added some slicer-generated dowel connectors:



With the stock geometry recreated, I can work on modifying it to accommodate both the braces and the tilted filter. Got some ideas flying around in my mind already for how to approach that. More to come.

Sidenote, since I essentially made a 1:1 replica of the piece, anyone can print it out without modification and save ~1.2 kg. Who's up to be the test fit guinea pig? Hit me up and I'll send you the stl (I'll distribute widely once fitment is validated).

[heinzboehmer]

Nice WORK!

This sounds more and more like a MUST do, IMO you should be damn proud of what you have pulled off.

I am so curious how must of an impact this will have on my convertible.

Appreciate it!

It should still make a difference. Hard to quantify how much, but it'll for sure help with strut tower deflection in a similar way as it does on the coupe.

That's amazing! Great work

Thanks!

Had another friend drive it a few days ago and he was similarly blown away. Hell yeah.

[0-60motorsports]

Did a B-A-B test with a friend today and confirmed that I'm not crazy!

Started with the braces on, drove around the block, removed them, drove around the block, put them back on, drove. He was skeptical that they would make much of a difference, but once the car got up to speed (~30 mph), he immediately noticed a difference. He was kinda blown away by how different the car felt to drive with and without the braces. Felt pretty proud when I saw that reaction

Anyway, firewall plug CAD is almost there. Should be able to start cutting/printing soon.

That's amazing! Great work

[Ramage]

Did a B-A-B test with a friend today and confirmed that I'm not crazy!

Started with the braces on, drove around the block, removed them, drove around the block, put them back on, drove. He was skeptical that they would make much of a difference, but once the car got up to speed (~30 mph), he immediately noticed a difference. He was kinda blown away by how different the car felt to drive with and without the braces. Felt pretty proud when I saw that reaction

Anyway, firewall plug CAD is almost there. Should be able to start cutting/printing soon.

Nice WORK!

This sounds more and more like a MUST do, IMO you should be damn proud of what you have pulled off.

I am so curious how must of an impact this will have on my convertible.

[heinzboehmer]

Did a B-A-B test with a friend today and confirmed that I'm not crazy!

Started with the braces on, drove around the block, removed them, drove around the block, put them back on, drove. He was skeptical that they would make much of a difference, but once the car got up to speed (~30 mph), he immediately noticed a difference. He was kinda blown away by how different the car felt to drive with and without the braces. Felt pretty proud when I saw that reaction

Anyway, firewall plug CAD is almost there. Should be able to start cutting/printing soon.

[D-O]

I was thinking something like this combo would work, but I need to take a better look to see if 22mm OD is too big.

https://www.probolt-usa.com/titanium-countersunk-washer-m6-22mm-od/

https://www.probolt-usa.com/titanium-countersunk-bolt-m6x1-00mmx20mm/

Titanium for the weight saving for my vert...

heinzboehmer apologies for the journal hi-jack

I was thinking something similar but with a rubber or plastic washer, but never mind that. Titanium FTW.

[Ramage]

I was thinking something like this combo would work, but I need to take a better look to see if 22mm OD is too big.

https://www.probolt-usa.com/titanium-countersunk-washer-m6-22mm-od/

https://www.probolt-usa.com/titanium-countersunk-bolt-m6x1-00mmx20mm/

Titanium for the weight saving for my vert...

heinzboehmer apologies for the journal hi-jack

[Ramage]

I’ve seen at least three different versions of those tabs all produced by Karbonius. There’s a ‘linear’ tab, and large diameter and a small diameter. Heinz and I have the small diameter.

We’re all nuts here, but the details matter!

Thanks!

The tabs on mine look like they are plastic, but I guess they could be anodized aluminum.


It also came with this key chain which appears to be made on the same 3D printer that the battery cable holder attached the airbox was made on.

[karter16]

Oh thread is different on the BMW bolts? That's no fun.

Yup the OE ones are M5 and the Karb uses M6. I found out the hard way 🙃

[heinzboehmer]

The factory BMW bolts, which are a different thread size, have a captive washer, so not as fiddly to install/uninstall.

Oh thread is different on the BMW bolts? That's no fun.

[Slideways]

I'm still using the Karbonius hardware and noticed the screws and washers you're using. I'm wondering if Karbonius updated their design over time, as the pegs holding the non-filtered side of my airbox seem different. I'll snap some photos to confirm and share them to tie up loose ends.

I'm considering switching to countersunk washers and screws for a sleeker look and better load distribution on the tabs. Do you happen to remember the outer diameter of the washers you're using?

Yep, I can confirm I see how ridiculous my last question is after reading it out loud

You can only pick one thing to remember:

A: OD of 4 washers used on my car a few years ago.
B: Cherished childhood memory.

Mad respect for all the stuff you have done, these journals are both awesome and fear inducing (mostly for my wallet).

Karbonius has been using the hex style hardware since day one. Only difference now is that they are matte black rather than silver. Since they do not have a washer, the head of the fastener will dig into the clear coat as you tighten it and this can damage the clear coat over time.

With a OE style torx bolt and washer combo, the washer sits flat against the clear coat and it prevents the surface from being damaged by the bolt being clamped down. Installation is a little fiddly since you have to center the washer for aesthetic reasons and you have to be careful during removal to not drop the washers into the abyss. The factory BMW bolts, which are a different thread size, have a captive washer, so not as fiddly to install/uninstall.