Black & Tan 332iT

[Obioban]

Given any thought to moving the lower mount points downward, to restore geometry for lowered cars?

[Obioban]

I can feel the weight savings in my wallet, looking at these pictures 🤣

[George Hill]

I didn't want to steal @Bryson thunder, but I have been man handling the latest design for a couple days now and its really impressive.

The part is 255mm "tall" and my printer max dimension is 256mm so pretty tight, but we got it fitted. After a couple fails I got a mostly "perfect" print.










The ball joint inserts printed in a different color and press nicely into the knuckle (and yes, I realize I could have picked a better color lol)




I really thought this was cool to see the evolution of his design and idea. The red one is the very "first" design compared to now. Bryson will correct me if I am wrong but if I recall the green one is stronger but still the same weight as the red one.

[Bry5on]

Ran a quick analysis on the stock parts assuming they're a similar enough material to 4340 and here we go - large deformations leading to camber loss. 11.5mm of displacement at the strut tower ~= 1 degree of camber. So at 1.6G, the factory parts are losing 7.2/11.5 = 0.63 degrees of camber, compare this with 2.0/11.5 = 0.174 degrees of camber in the latest knuckle version. Excellent.

[Bry5on]

Thanks guys, I’m enjoying this project as it’s giving me a chance to really test out Fusion 360 and generative design.


Tonight I worked on some lightweighting and managed to get this down to a .09kg weight penalty over the single clamp version. So we’re pretty much maintaining the 1lb (.92lb) unsprung mass reduction. Pretty good I’ll say!

And thanks to a member on e46fanatics we now have a visual and measurement of heatshield clearance - 3.25mm to the rotor - snug.

The latest:


Off to the printer(s) we go! (George is printing one too)

[D-O]

Wow. Just wow...

[enjoy_m3]

Very cool, so many cool parts comming between you and the carbon doors. Excited about building my wagon, funding not so much, lol. I have a set of f80 brakes sitting if you need to test fit.

[Bry5on]

That thing is spooky! Nothing like anything I've seen. Is your 1.6G load testing peak or average load test? What happens when you hit a hard bump at full load?

What is the issue re clearance to ZCP rotor? Isn't your rotor mounting surface distance to the tie rod equal to stock when looking down on the Z axis? If geometry is staying the same, then those parameters should all be equal, including clearance, no? I'll have to give you my stock clearance of my BBK, which Heinz notably pointed out the PO cut the shield or else I'd give you the measurements you're looking for

Yeah the output is pretty wild. I used some conservative numbers in there (full half car weight on the strut), extra loads for dynamic steering inputs at the limit, and also chose 1.6G as a pretty conservative limit case. The rest is taken up by the safety factor.

Clearance to the ZCP rotor is really just for verification purpose as I never scanned a rotor, even though it's the same as stock (plus those heat shields were a little bent . Trying to make sure I validate all possible mistakes here before I place any expensive orders. I got a STEP file of the ZCP rotors so I'll print a section and do a digital and physical test fit shortly!

[YoitsTmac]

That thing is spooky! Nothing like anything I've seen. Is your 1.6G load testing peak or average load test? What happens when you hit a hard bump at full load?

What is the issue re clearance to ZCP rotor? Isn't your rotor mounting surface distance to the tie rod equal to stock when looking down on the Z axis? If geometry is staying the same, then those parameters should all be equal, including clearance, no? I'll have to give you my stock clearance of my BBK, which Heinz notably pointed out the PO cut the shield or else I'd give you the measurements you're looking for

[Bry5on]

To keep the DSC happy?

Just manually write the non-m ratio into the DSC using NCS expert, and done. No problems with DSC

[Obioban]

I'm not sure why anyone would really prefer the ZCP/CSL steering ratio over the non-m ratio

To keep the DSC happy?

[Bry5on]

Freaking amazing.

... we need a configurator. Choose your own caliper/steering rack :P

Have you priced out metal 3D printing a pair?

Ha, yeah. The easiest addition is actually the F80 M3 brakes, as it's just a matter of moving the brake caliper mounting bosses 3mm toward the inside of the car and re-running the analysis. And honestly I'm not sure why anyone would really prefer the ZCP/CSL steering ratio over the non-m ratio

I've priced out printing, yeah - it's a few grand per pair, then you need to add the four machined 4340 inserts into the picture.

We've now shaved it down to a .09kg weight penalty vs the single clamp version - I think I'm going to call this done:

[Obioban]

Alright, I forked out the $400 for a Fusion subscription and generative design tokens and finally ran the double clamp version of the steering knuckle.. You'll note in this version that we've reduced displacement at the top of the strut tube to 2mm, which now means <.2 degrees of camber loss at 1.6G corner loads, and we've introduced a simpler to machine pair of inserts in the control arms and tie rods. You'll also see that I didn't explore the saddle clamp idea as it would have been a mass penalty. This double clamp version is only .15kg heavier than the single clamp version and there's technically room for me to optimize this even further to get down to weight-neutral.

Anyway, lots of pictures of the parts tell the story:


And on to the simulation results:

Freaking amazing.

... we need a configurator. Choose your own caliper/steering rack :P

Have you priced out metal 3D printing a pair?

[Bry5on]

Alright, I forked out the $400 for a Fusion subscription and generative design tokens and finally ran the double clamp version of the steering knuckle.. You'll note in this version that we've reduced displacement at the top of the strut tube to 2mm, which now means <.2 degrees of camber loss at 1.6G corner loads, and we've introduced a simpler to machine pair of inserts in the control arms and tie rods. You'll also see that I didn't explore the saddle clamp idea as it would have been a mass penalty. This double clamp version is only .15kg heavier than the single clamp version and there's technically room for me to optimize this even further to get down to weight-neutral.

Anyway, lots of pictures of the parts tell the story:


And on to the simulation results:

[Bry5on]

Test fit of the heat shield went well, miles of clearance to the tie rod and control arm. Definitely room to play with ackerman if one so desired, or to move KPI and scrub radius a bit.

Anyone here have a 3D section model of the CSL/ZCP or regular M3 brake rotor? Looking for a few key dimensions to verify clearance as I modeled my shield off of a factory M3 heat shield scan.