Black & Tan 332iT

[YoitsTmac]

Yeah at some point here I'll make the trip up. Or Heinz can scan it

I need to schedule time with him. I'll just bring that as an item and we can scan it for you!

[Bry5on]

I need to schedule time with him. I'll just bring that as an item and we can scan it for you!

Love it. Thank you!

[heinzboehmer]

I need to schedule time with him. I'll just bring that as an item and we can scan it for you!

Yep! Need to meet up with both you and Slideways in the not too distant future. The list of things to scan is growing longer every day

[Bry5on]

Thanks to YoitsTmac and heinzboehmer we've got an interesting finding. I've overlaid a non-m knuckle scan to an M3 knuckle scan, and the numbers do not match the BMW quoted steering ratios.

So here's what I've got for LCA to tie rod distance:
M3: 130mm
Non-m: 126mm
SuperKnuck: 122.9mm

That means that if M3 CSL/ZCP is 14.5:1, then
Non-M: 14.05:1
SuperKnuck: 13.7:1

And consequently, if the non-M is 13.7:1, then
M3 CSL/ZCP: 14.13:1
SuperKnuck: 13.36:1

Now I'm going to have to pull up the numbers in NCS expert to see what the DSC module says. Guess that knuckle I ordered is a bit of a tighter steering ratio than planned!

Blue is M3, brown is non-m:

[YoitsTmac]

Insanely interesting to see the two overlapped. Looks like the caliper bracket position is tied more to the strut than the LCA.

The BMW community can always depend on me to have the most random parts lying around🫡. Got home and immediately chucked that thing in the bin.

[Flow]

The amount of knowledge in this thread is insane.
Thank you for doing all this and sharing it with the community !

[heinzboehmer]

Huh, that's surprising. Static camber and caster (and toe?) look different too?

I would trust the geometry of the pickup points for the LCA, tie rod, strut and caliper brackets in the scan. Not sure I'd trust the relation between the hub and the aforementioned features, though. The heat shield was hard to wrap the scan around.

What happens if you line the scans up on the LCA/caliper bracket mounting points? I would think those are the same between the M and non-M knuckles. Almost looks like the non-M tie rod pickup point would end up higher than the M one, resulting in a slight change in effective LCA to tie rod distance.

[Bry5on]

I lined them up on the mounting bosses for the heat shield as I believe that’s a shared part number. Lots of geometry tweaks, ones I’ve noted (M3):
- Caster (increase)
- Trail (increase)
- Inner tire clearance (slight increase from moving strut inboard)
- Ackerman (decrease)
- Scrub (increase)
- Bump steer (hard to say direction, but probably decrease)
- Caliper clocking, radial- and back-spacing

[heinzboehmer]

Oh, clever!

Kinda blown away by the findings. They're far more different than I though they were.

[Bry5on]

Oh, clever!

Kinda blown away by the findings. They're far more different than I though they were.

Honestly, same reaction I had. Almost didn’t believe my eyes as it’s clearly a derivative but a totally different forging.

First principles has the on center steering ratio at 16.33:1 for an M3 CSL/ZCP and 15.4:1 for my knuckle. Recall that the 992 ST is 15:1 in center, but 13.5:1 after accounting for wheelbase differences. So even with the ratio shorter than the non-m, we’re still a ways off the sports car.

[Obioban]

Need to get a scan of the CSL's in the mix.

[Bry5on]

First Article has arrived. Overall it looks pretty good, feels very beefy, and they didn't take too much off anywhere for cleanup of support material. Even the M6 threads printed out reasonably well and just needed cleanup with a tap - pretty wild. All hole bores came in under by ~0.2mm, so I'll open up a couple of the clearance holes before printing the next part, but other than that, I think this is ready for prime time.

Next up, have to machine the LCA and tie rod inserts, heat treat/quench the part, open up the hub locating bore, finish the bores of the LCA and tie rod mating interference fits, then this thing is ready for install. Wild!

Thanks to all the folks running the mullet tune, the proceeds have made this project possible.

[karter16]

This is such an incredible project! 2005-me would have been blown away to imagine this being in the realms of possibility for an individual to achieve!

[Bry5on]

This is such an incredible project! 2005-me would have been blown away to imagine this being in the realms of possibility for an individual to achieve!

Seriously, that makes two of us. Very cool to have been able to use both generative design and 3D printing for a personal project! The last 3D printing project I was involved with was very much more complex than this, it’s pretty incredible what you can do nowadays.

[Bry5on]

Okay, good news and bad news. Good news is that I ordered the other side printed knuckle and it's already on its way over the pacific to me.

Bad news unfortunately is more than the good news:
1) I neglected to realize that I couldn't simply mirror the ABS mounting orientation, as the sensor is not centered through its bore. I'll need to come up with a solution for this, have some ideas, but it's an annoying problem to have.
2) The large hand reamers showed up and I reamed the bores for the LCA and tie rod inserts. The bores *did not* clean up with the reamers. So it looks like my caliper measurements were wrong and the bores did not come in undersized like I thought. We'll see if the next batch is the same. Currently debating whether I order some adjustable hand reamers, or chance it and use a press-fit adhesive to take up the slack.
3) I opened up the strut clamp bore on the new part and probably shouldn't have. The holes came in a little ovaled, and now I think I'll need to find an actual solution to this problem to make them round. Aluminum tape will do for shimming the oversized hole, but I'll need a way to fixture it straight which could be challenging.



I also got to an oil change this weekend. Well, turns out that the preventative timesert that I did in my oil pan drain plug hole didn't swage in properly, or I used the wrong grip length. It was pulling out instead of the fastener.

I wasn't prepared to deal with that problem, so I change the oil from the top by sucking it from the dipstick tube. And well I use the CSL dipstick tube, so that meant removing the Slon brace and the front half of the intake. Normally not a big deal, but the vacuum port on my karbonius airbox had debonded a while back, and I knew I'd have to fix this next time the airbox was off, or I wouldn't be able to reconnect that vacuum tube.



So, some epoxy later and that was fixed. And that 15 minute oil change was done 3.5 hours later.



I also learned something very interesting. The e46 cabrio uses different seat mount points. Mount points that are 40mm narrower on the outside vs the non-cab. *checks math* - why yes, that's the same dimension as the e90/f80/etc seats.. so you're telling me there's a way to run the lovely vented/heated M3cs seats in the e46 if we use cabrio seat mounts? I'm intrigued.



And one more thing. Thanks to EthanolTurbo I've got his F80-e46 M3 modified carbon driveshaft on the bench to measure and test. More detailed numbers here: https://nam3forum.com/forums/forum/m...945#post318945